> Part of the walkerOS documentation. Project overview and full index: # Google Pub/Sub [Server](#)[ Source code](https://github.com/elbwalker/walkerOS/tree/main/packages/server/destinations/gcp)[ Package](https://www.npmjs.com/package/@walkeros/server-destination-gcp) Server-side event publishing to [Google Cloud Pub/Sub](https://cloud.google.com/pubsub) topics. Each event is serialized as JSON, optionally keyed for per-message ordering, and published via the official `@google-cloud/pubsub` SDK. Supports Application Default Credentials, service account JSON, or pre-configured client injection. Per-rule topic, ordering-key, and attribute overrides. Idempotent topic provisioning with EU storage policy by default. The destination ships inside `@walkeros/server-destination-gcp` alongside BigQuery; install the package once and import `destinationPubSub` for Pub/Sub. Where this fits Pub/Sub is a **server destination** in the walkerOS flow: Publishes events to a Pub/Sub topic for fan-out, asynchronous processing, cross-region delivery, and integration with downstream consumers (Dataflow, Cloud Functions, Cloud Run, custom subscribers). ## Installation[​](#installation "Direct link to Installation") ```bash npm install @walkeros/server-destination-gcp ``` * Integrated * Bundled ```typescript import { startFlow } from '@walkeros/collector'; import { destinationPubSub } from '@walkeros/server-destination-gcp'; await startFlow({ destinations: { pubsub: { code: destinationPubSub, config: { settings: { projectId: 'YOUR_PROJECT_ID', topic: 'events', }, }, }, }, }); ``` Add to your `flow.json` destinations: ```json "destinations": { "pubsub": { "package": "@walkeros/server-destination-gcp", "import": "destinationPubSub", "config": { "settings": { "projectId": "YOUR_PROJECT_ID", "topic": "events" } } } } ``` [See bundled mode setup](/preview/pr-749/docs/getting-started/modes/bundled.md) | [CLI reference](/preview/pr-749/docs/apps/cli.md) ## Configuration[​](#configuration "Direct link to Configuration") This destination uses the standard destination config wrapper (consent, data, env, id, ...). For the shared fields see [destination configuration](/docs/destinations#configuration). Package-specific fields live under `config.settings` and are listed below. ## Settings[​](#settings "Direct link to Settings") | Property | Type | Description | More | | ------------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | | `client` | `any` | Google Cloud Pub/Sub client instance | | | `projectId*` | `string` | Google Cloud Project ID | | | `topic*` | `string` | Pub/Sub topic short name (like events). The full resource name projects/\/topics/\ is built by the SDK. | | | `credentials` | `any` | Service account credentials as a JSON string or an object with client\_email and private\_key. Default: Application Default Credentials (ADC). (deprecated: use config.credentials) | | | `apiEndpoint` | `string` | Override Pub/Sub API endpoint. Useful for the local emulator (like localhost:8085). | | | `orderingKey` | `any` | Mapping value resolved per-event. Truthy enables per-key ordering for the publish. | | | `attributes` | `any` | Default per-event attribute map merged into every published message. Mapping.Map shape. | | \* Required fields ## Mapping[​](#mapping "Direct link to Mapping") Per-event rules under `config.mapping`. For the standard rule fields (consent, condition, data, batch, name, policy) see [mapping](/docs/mapping). | Property | Type | Description | More | | ------------- | -------- | ----------------------------------------------------------------------------- | ---- | | `topic` | `string` | Per-rule topic override. Falls back to settings.topic if absent. | | | `orderingKey` | `any` | Per-rule ordering-key Mapping.Value. Overrides settings.orderingKey when set. | | | `attributes` | `any` | Per-rule attribute Mapping.Map merged on top of settings.attributes. | | ## Examples ### Default publish An event is published to the configured Pub/Sub topic with the full JSON event as the message body and no ordering key. Event ```json { "name": "order complete", "data": { "id": "ORD-500", "total": 199.99, "currency": "EUR" }, "context": { "shopping": [ "complete", 0 ] }, "globals": { "pagegroup": "shop" }, "custom": { "completely": "random" }, "user": { "id": "usr-789" }, "nested": [ { "entity": "product", "data": { "id": "ers", "name": "Everyday Ruck Snack", "color": "black", "size": "l", "price": 420 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "product", "data": { "id": "cc", "name": "Cool Cap", "size": "one size", "price": 42 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "gift", "data": { "name": "Surprise" }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] } ], "consent": { "functional": true }, "id": "52597d5269679369", "trigger": "load", "entity": "order", "action": "complete", "timestamp": 1700001100, "timing": 3.14, "source": { "count": 1, "trace": "1a2b3c4d5e6f70819a2b3c4d5e6f7081", "type": "express", "platform": "server" } } ``` Out ```javascript topic("events", { "messageOrdering": false }); publishMessage("events", { "data": { "0": 123, "1": 34, "2": 110, "3": 97, "4": 109, "5": 101, "6": 34, "7": 58, "8": 34, "9": 111, "10": 114, "11": 100, "12": 101, "13": 114, "14": 32, "15": 99, "16": 111, "17": 109, "18": 112, "19": 108, "20": 101, "21": 116, "22": 101, "23": 34, "24": 44, "25": 34, "26": 100, "27": 97, "28": 116, "29": 97, "30": 34, "31": 58, "32": 123, "33": 34, "34": 105, "35": 100, "36": 34, "37": 58, "38": 34, "39": 79, "40": 82, "41": 68, "42": 45, "43": 53, "44": 48, "45": 48, "46": 34, "47": 44, "48": 34, "49": 116, "50": 111, "51": 116, "52": 97, "53": 108, "54": 34, "55": 58, "56": 49, "57": 57, "58": 57, "59": 46, "60": 57, "61": 57, "62": 44, "63": 34, "64": 99, "65": 117, "66": 114, "67": 114, "68": 101, "69": 110, "70": 99, "71": 121, "72": 34, "73": 58, "74": 34, "75": 69, "76": 85, "77": 82, "78": 34, "79": 125, "80": 44, "81": 34, "82": 99, "83": 111, "84": 110, "85": 116, "86": 101, "87": 120, "88": 116, "89": 34, "90": 58, "91": 123, "92": 34, "93": 115, "94": 104, "95": 111, "96": 112, "97": 112, "98": 105, "99": 110, "100": 103, "101": 34, "102": 58, "103": 91, "104": 34, "105": 99, "106": 111, "107": 109, "108": 112, "109": 108, "110": 101, "111": 116, "112": 101, "113": 34, "114": 44, "115": 48, "116": 93, "117": 125, "118": 44, "119": 34, "120": 103, "121": 108, "122": 111, "123": 98, "124": 97, "125": 108, "126": 115, "127": 34, "128": 58, "129": 123, "130": 34, "131": 112, "132": 97, "133": 103, "134": 101, "135": 103, "136": 114, "137": 111, "138": 117, "139": 112, "140": 34, "141": 58, "142": 34, "143": 115, "144": 104, "145": 111, "146": 112, "147": 34, "148": 125, "149": 44, "150": 34, "151": 99, "152": 117, "153": 115, "154": 116, "155": 111, "156": 109, "157": 34, "158": 58, "159": 123, "160": 34, "161": 99, "162": 111, "163": 109, "164": 112, "165": 108, "166": 101, "167": 116, "168": 101, "169": 108, "170": 121, "171": 34, "172": 58, "173": 34, "174": 114, "175": 97, "176": 110, "177": 100, "178": 111, "179": 109, "180": 34, "181": 125, "182": 44, "183": 34, "184": 117, "185": 115, "186": 101, "187": 114, "188": 34, "189": 58, "190": 123, "191": 34, "192": 105, "193": 100, "194": 34, "195": 58, "196": 34, "197": 117, "198": 115, "199": 114, "200": 45, "201": 55, "202": 56, "203": 57, "204": 34, "205": 125, "206": 44, "207": 34, "208": 110, "209": 101, "210": 115, "211": 116, "212": 101, "213": 100, "214": 34, "215": 58, "216": 91, "217": 123, "218": 34, "219": 101, "220": 110, "221": 116, "222": 105, "223": 116, "224": 121, "225": 34, "226": 58, "227": 34, "228": 112, "229": 114, "230": 111, "231": 100, "232": 117, "233": 99, "234": 116, "235": 34, "236": 44, "237": 34, "238": 100, "239": 97, "240": 116, "241": 97, "242": 34, "243": 58, "244": 123, "245": 34, "246": 105, "247": 100, "248": 34, "249": 58, "250": 34, "251": 101, "252": 114, "253": 115, "254": 34, "255": 44, "256": 34, "257": 110, "258": 97, 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"519": 116, "520": 121, "521": 34, "522": 58, "523": 34, "524": 103, "525": 105, "526": 102, "527": 116, "528": 34, "529": 44, "530": 34, "531": 100, "532": 97, "533": 116, "534": 97, "535": 34, "536": 58, "537": 123, "538": 34, "539": 110, "540": 97, "541": 109, "542": 101, "543": 34, "544": 58, "545": 34, "546": 83, "547": 117, "548": 114, "549": 112, "550": 114, "551": 105, "552": 115, "553": 101, "554": 34, "555": 125, "556": 44, "557": 34, "558": 99, "559": 111, "560": 110, "561": 116, "562": 101, "563": 120, "564": 116, "565": 34, "566": 58, "567": 123, "568": 34, "569": 115, "570": 104, "571": 111, "572": 112, "573": 112, "574": 105, "575": 110, "576": 103, "577": 34, "578": 58, "579": 91, "580": 34, "581": 99, "582": 111, "583": 109, "584": 112, "585": 108, "586": 101, "587": 116, "588": 101, "589": 34, "590": 44, "591": 48, "592": 93, "593": 125, "594": 44, "595": 34, "596": 110, "597": 101, "598": 115, "599": 116, "600": 101, "601": 100, "602": 34, "603": 58, "604": 91, 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"692": 100, "693": 101, "694": 114, "695": 34, "696": 44, "697": 34, "698": 97, "699": 99, "700": 116, "701": 105, "702": 111, "703": 110, "704": 34, "705": 58, "706": 34, "707": 99, "708": 111, "709": 109, "710": 112, "711": 108, "712": 101, "713": 116, "714": 101, "715": 34, "716": 44, "717": 34, "718": 116, "719": 105, "720": 109, "721": 101, "722": 115, "723": 116, "724": 97, "725": 109, "726": 112, "727": 34, "728": 58, "729": 49, "730": 55, "731": 48, "732": 48, "733": 48, "734": 48, "735": 49, "736": 49, "737": 48, "738": 48, "739": 44, "740": 34, "741": 116, "742": 105, "743": 109, "744": 105, "745": 110, "746": 103, "747": 34, "748": 58, "749": 51, "750": 46, "751": 49, "752": 52, "753": 44, "754": 34, "755": 115, "756": 111, "757": 117, "758": 114, "759": 99, "760": 101, "761": 34, "762": 58, "763": 123, "764": 34, "765": 99, "766": 111, "767": 117, "768": 110, "769": 116, "770": 34, "771": 58, "772": 49, "773": 44, "774": 34, "775": 116, "776": 114, "777": 97, "778": 99, "779": 101, "780": 34, "781": 58, "782": 34, "783": 49, "784": 97, "785": 50, "786": 98, "787": 51, "788": 99, "789": 52, "790": 100, "791": 53, "792": 101, "793": 54, "794": 102, "795": 55, "796": 48, "797": 56, "798": 49, "799": 57, "800": 97, "801": 50, "802": 98, "803": 51, "804": 99, "805": 52, "806": 100, "807": 53, "808": 101, "809": 54, "810": 102, "811": 55, "812": 48, "813": 56, "814": 49, "815": 34, "816": 44, "817": 34, "818": 116, "819": 121, "820": 112, "821": 101, "822": 34, "823": 58, "824": 34, "825": 101, "826": 120, "827": 112, "828": 114, "829": 101, "830": 115, "831": 115, "832": 34, "833": 44, "834": 34, "835": 112, "836": 108, "837": 97, "838": 116, "839": 102, "840": 111, "841": 114, "842": 109, "843": 34, "844": 58, "845": 34, "846": 115, "847": 101, "848": 114, "849": 118, "850": 101, "851": 114, "852": 34, "853": 44, "854": 34, "855": 114, "856": 101, "857": 108, "858": 101, "859": 97, "860": 115, "861": 101, "862": 34, "863": 58, "864": 123, "865": 34, "866": 115, "867": 101, "868": 114, "869": 118, "870": 101, "871": 114, "872": 34, "873": 58, "874": 34, "875": 52, "876": 46, "877": 56, "878": 46, "879": 48, "880": 34, "881": 125, "882": 125, "883": 125 } }) ``` ### Mapped attributes A mapping resolves a per-event attribute map, here exposing entity and action as Pub/Sub attributes for routing in subscribers. Event ```json { "name": "order complete", "data": { "id": "ORD-500", "total": 199.99, "currency": "EUR" }, "context": { "shopping": [ "complete", 0 ] }, "globals": { "pagegroup": "shop" }, "custom": { "completely": "random" }, "user": { "id": "usr-789" }, "nested": [ { "entity": "product", "data": { "id": "ers", "name": "Everyday Ruck Snack", "color": "black", "size": "l", "price": 420 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "product", "data": { "id": "cc", "name": "Cool Cap", "size": "one size", "price": 42 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "gift", "data": { "name": "Surprise" }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] } ], "consent": { "functional": true }, "id": "52597d5269679369", "trigger": "load", "entity": "order", "action": "complete", "timestamp": 1700001100, "timing": 3.14, "source": { "count": 1, "trace": "1a2b3c4d5e6f70819a2b3c4d5e6f7081", "type": "express", "platform": "server" } } ``` Mapping ```json { "settings": { "attributes": { "entity": "entity", "action": "action" } } } ``` Out ```javascript topic("events", { "messageOrdering": false }); publishMessage("events", { "data": { "0": 123, "1": 34, "2": 110, "3": 97, "4": 109, "5": 101, "6": 34, "7": 58, "8": 34, "9": 111, "10": 114, "11": 100, "12": 101, "13": 114, "14": 32, "15": 99, "16": 111, "17": 109, "18": 112, "19": 108, "20": 101, "21": 116, "22": 101, "23": 34, "24": 44, "25": 34, "26": 100, "27": 97, "28": 116, "29": 97, "30": 34, "31": 58, "32": 123, "33": 34, "34": 105, "35": 100, "36": 34, "37": 58, "38": 34, "39": 79, "40": 82, "41": 68, "42": 45, "43": 53, "44": 48, "45": 48, "46": 34, "47": 44, "48": 34, "49": 116, "50": 111, "51": 116, "52": 97, "53": 108, "54": 34, "55": 58, "56": 49, "57": 57, "58": 57, "59": 46, "60": 57, "61": 57, "62": 44, "63": 34, "64": 99, "65": 117, "66": 114, "67": 114, "68": 101, "69": 110, "70": 99, "71": 121, "72": 34, "73": 58, "74": 34, "75": 69, "76": 85, "77": 82, "78": 34, "79": 125, "80": 44, "81": 34, "82": 99, "83": 111, "84": 110, "85": 116, "86": 101, "87": 120, "88": 116, "89": 34, "90": 58, "91": 123, "92": 34, "93": 115, "94": 104, "95": 111, "96": 112, "97": 112, "98": 105, "99": 110, "100": 103, "101": 34, "102": 58, "103": 91, "104": 34, "105": 99, "106": 111, "107": 109, "108": 112, "109": 108, "110": 101, "111": 116, "112": 101, "113": 34, "114": 44, "115": 48, "116": 93, "117": 125, "118": 44, "119": 34, "120": 103, "121": 108, "122": 111, "123": 98, "124": 97, "125": 108, "126": 115, "127": 34, "128": 58, "129": 123, "130": 34, "131": 112, "132": 97, "133": 103, "134": 101, "135": 103, "136": 114, "137": 111, "138": 117, "139": 112, "140": 34, "141": 58, "142": 34, "143": 115, "144": 104, "145": 111, "146": 112, "147": 34, "148": 125, "149": 44, "150": 34, "151": 99, "152": 117, "153": 115, "154": 116, "155": 111, "156": 109, "157": 34, "158": 58, "159": 123, "160": 34, "161": 99, "162": 111, "163": 109, 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34, "251": 101, "252": 114, "253": 115, "254": 34, "255": 44, "256": 34, "257": 110, "258": 97, "259": 109, "260": 101, "261": 34, "262": 58, "263": 34, "264": 69, "265": 118, "266": 101, "267": 114, "268": 121, "269": 100, "270": 97, "271": 121, "272": 32, "273": 82, "274": 117, "275": 99, "276": 107, "277": 32, "278": 83, "279": 110, "280": 97, "281": 99, "282": 107, "283": 34, "284": 44, "285": 34, "286": 99, "287": 111, "288": 108, "289": 111, "290": 114, "291": 34, "292": 58, "293": 34, "294": 98, "295": 108, "296": 97, "297": 99, "298": 107, "299": 34, "300": 44, "301": 34, "302": 115, "303": 105, "304": 122, "305": 101, "306": 34, "307": 58, "308": 34, "309": 108, "310": 34, "311": 44, "312": 34, "313": 112, "314": 114, "315": 105, "316": 99, "317": 101, "318": 34, "319": 58, "320": 52, "321": 50, "322": 48, "323": 125, "324": 44, "325": 34, "326": 99, "327": 111, "328": 110, "329": 116, "330": 101, "331": 120, "332": 116, "333": 34, "334": 58, "335": 123, "336": 34, "337": 115, 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111, "425": 108, "426": 32, "427": 67, "428": 97, "429": 112, "430": 34, "431": 44, "432": 34, "433": 115, "434": 105, "435": 122, "436": 101, "437": 34, "438": 58, "439": 34, "440": 111, "441": 110, "442": 101, "443": 32, "444": 115, "445": 105, "446": 122, "447": 101, "448": 34, "449": 44, "450": 34, "451": 112, "452": 114, "453": 105, "454": 99, "455": 101, "456": 34, "457": 58, "458": 52, "459": 50, "460": 125, "461": 44, "462": 34, "463": 99, "464": 111, "465": 110, "466": 116, "467": 101, "468": 120, "469": 116, "470": 34, "471": 58, "472": 123, "473": 34, "474": 115, "475": 104, "476": 111, "477": 112, "478": 112, "479": 105, "480": 110, "481": 103, "482": 34, "483": 58, "484": 91, "485": 34, "486": 99, "487": 111, "488": 109, "489": 112, "490": 108, "491": 101, "492": 116, "493": 101, "494": 34, "495": 44, "496": 48, "497": 93, "498": 125, "499": 44, "500": 34, "501": 110, "502": 101, "503": 115, "504": 116, "505": 101, "506": 100, "507": 34, "508": 58, "509": 91, "510": 93, 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"771": 58, "772": 49, "773": 44, "774": 34, "775": 116, "776": 114, "777": 97, "778": 99, "779": 101, "780": 34, "781": 58, "782": 34, "783": 49, "784": 97, "785": 50, "786": 98, "787": 51, "788": 99, "789": 52, "790": 100, "791": 53, "792": 101, "793": 54, "794": 102, "795": 55, "796": 48, "797": 56, "798": 49, "799": 57, "800": 97, "801": 50, "802": 98, "803": 51, "804": 99, "805": 52, "806": 100, "807": 53, "808": 101, "809": 54, "810": 102, "811": 55, "812": 48, "813": 56, "814": 49, "815": 34, "816": 44, "817": 34, "818": 116, "819": 121, "820": 112, "821": 101, "822": 34, "823": 58, "824": 34, "825": 101, "826": 120, "827": 112, "828": 114, "829": 101, "830": 115, "831": 115, "832": 34, "833": 44, "834": 34, "835": 112, "836": 108, "837": 97, "838": 116, "839": 102, "840": 111, "841": 114, "842": 109, "843": 34, "844": 58, "845": 34, "846": 115, "847": 101, "848": 114, "849": 118, "850": 101, "851": 114, "852": 34, "853": 44, "854": 34, "855": 114, "856": 101, "857": 108, "858": 101, "859": 97, "860": 115, "861": 101, "862": 34, "863": 58, "864": 123, "865": 34, "866": 115, "867": 101, "868": 114, "869": 118, "870": 101, "871": 114, "872": 34, "873": 58, "874": 34, "875": 52, "876": 46, "877": 56, "878": 46, "879": 48, "880": 34, "881": 125, "882": 125, "883": 125 }, "attributes": { "entity": "order", "action": "complete" } }) ``` ### Mapped payload A data mapping transforms the event payload before publish. The rewritten object becomes the Pub/Sub message body. Event ```json { "name": "order complete", "data": { "id": "ORD-500", "total": 199.99, "currency": "EUR" }, "context": { "shopping": [ "complete", 0 ] }, "globals": { "pagegroup": "shop" }, "custom": { "completely": "random" }, "user": { "id": "usr-789" }, "nested": [ { "entity": "product", "data": { "id": "ers", "name": "Everyday Ruck Snack", "color": "black", "size": "l", "price": 420 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "product", "data": { "id": "cc", "name": "Cool Cap", "size": "one size", "price": 42 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "gift", "data": { "name": "Surprise" }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] } ], "consent": { "functional": true }, "id": "52597d5269679369", "trigger": "load", "entity": "order", "action": "complete", "timestamp": 1700001100, "timing": 3.14, "source": { "count": 1, "trace": "1a2b3c4d5e6f70819a2b3c4d5e6f7081", "type": "express", "platform": "server" } } ``` Mapping ```json { "data": { "map": { "order_id": "data.id", "revenue": "data.total", "currency": "data.currency" } } } ``` Out ```javascript topic("events", { "messageOrdering": false }); publishMessage("events", { "data": { "0": 123, "1": 34, "2": 111, "3": 114, "4": 100, "5": 101, "6": 114, "7": 95, "8": 105, "9": 100, "10": 34, "11": 58, "12": 34, "13": 79, "14": 82, "15": 68, "16": 45, "17": 53, "18": 48, "19": 48, "20": 34, "21": 44, "22": 34, "23": 114, "24": 101, "25": 118, "26": 101, "27": 110, "28": 117, "29": 101, "30": 34, "31": 58, "32": 49, "33": 57, "34": 57, "35": 46, "36": 57, "37": 57, "38": 44, "39": 34, "40": 99, "41": 117, "42": 114, "43": 114, "44": 101, "45": 110, "46": 99, "47": 121, "48": 34, "49": 58, "50": 34, "51": 69, "52": 85, "53": 82, "54": 34, "55": 125 } }) ``` ### Ordering key from user A mapping resolves the ordering key from event.user.id, enabling per-user ordering for this publish. Event ```json { "name": "order complete", "data": { "id": "ORD-500", "total": 199.99, "currency": "EUR" }, "context": { "shopping": [ "complete", 0 ] }, "globals": { "pagegroup": "shop" }, "custom": { "completely": "random" }, "user": { "id": "usr-789" }, "nested": [ { "entity": "product", "data": { "id": "ers", "name": "Everyday Ruck Snack", "color": "black", "size": "l", "price": 420 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "product", "data": { "id": "cc", "name": "Cool Cap", "size": "one size", "price": 42 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "gift", "data": { "name": "Surprise" }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] } ], "consent": { "functional": true }, "id": "52597d5269679369", "trigger": "load", "entity": "order", "action": "complete", "timestamp": 1700001100, "timing": 3.14, "source": { "count": 1, "trace": "1a2b3c4d5e6f70819a2b3c4d5e6f7081", "type": "express", "platform": "server" } } ``` Mapping ```json { "settings": { "orderingKey": "user.id" } } ``` Out ```javascript topic("events", { "messageOrdering": true }); publishMessage("events", { "data": { "0": 123, "1": 34, "2": 110, "3": 97, "4": 109, "5": 101, "6": 34, "7": 58, "8": 34, "9": 111, "10": 114, "11": 100, "12": 101, "13": 114, "14": 32, "15": 99, "16": 111, "17": 109, "18": 112, "19": 108, "20": 101, "21": 116, "22": 101, "23": 34, "24": 44, "25": 34, "26": 100, "27": 97, "28": 116, "29": 97, "30": 34, "31": 58, "32": 123, "33": 34, "34": 105, "35": 100, "36": 34, "37": 58, "38": 34, "39": 79, "40": 82, "41": 68, "42": 45, "43": 53, "44": 48, "45": 48, "46": 34, "47": 44, "48": 34, "49": 116, "50": 111, "51": 116, "52": 97, "53": 108, "54": 34, "55": 58, "56": 49, "57": 57, "58": 57, "59": 46, "60": 57, "61": 57, "62": 44, "63": 34, "64": 99, "65": 117, "66": 114, "67": 114, "68": 101, "69": 110, "70": 99, "71": 121, "72": 34, "73": 58, "74": 34, "75": 69, "76": 85, "77": 82, "78": 34, "79": 125, "80": 44, "81": 34, "82": 99, "83": 111, "84": 110, "85": 116, "86": 101, "87": 120, "88": 116, "89": 34, "90": 58, "91": 123, "92": 34, "93": 115, "94": 104, "95": 111, "96": 112, "97": 112, "98": 105, "99": 110, "100": 103, "101": 34, "102": 58, "103": 91, "104": 34, "105": 99, "106": 111, "107": 109, "108": 112, "109": 108, "110": 101, "111": 116, "112": 101, "113": 34, "114": 44, "115": 48, "116": 93, "117": 125, "118": 44, "119": 34, "120": 103, "121": 108, "122": 111, "123": 98, "124": 97, "125": 108, "126": 115, "127": 34, "128": 58, "129": 123, "130": 34, "131": 112, "132": 97, "133": 103, "134": 101, "135": 103, "136": 114, "137": 111, "138": 117, "139": 112, "140": 34, "141": 58, "142": 34, "143": 115, "144": 104, "145": 111, "146": 112, "147": 34, "148": 125, "149": 44, "150": 34, "151": 99, "152": 117, "153": 115, "154": 116, "155": 111, "156": 109, "157": 34, "158": 58, "159": 123, "160": 34, "161": 99, "162": 111, "163": 109, "164": 112, "165": 108, "166": 101, "167": 116, "168": 101, "169": 108, "170": 121, "171": 34, "172": 58, "173": 34, "174": 114, "175": 97, "176": 110, "177": 100, "178": 111, "179": 109, "180": 34, "181": 125, "182": 44, "183": 34, "184": 117, "185": 115, "186": 101, "187": 114, "188": 34, "189": 58, "190": 123, "191": 34, "192": 105, "193": 100, "194": 34, "195": 58, "196": 34, "197": 117, "198": 115, "199": 114, "200": 45, "201": 55, "202": 56, "203": 57, "204": 34, "205": 125, "206": 44, "207": 34, "208": 110, "209": 101, "210": 115, "211": 116, "212": 101, "213": 100, "214": 34, "215": 58, "216": 91, "217": 123, "218": 34, "219": 101, "220": 110, "221": 116, "222": 105, "223": 116, "224": 121, "225": 34, "226": 58, "227": 34, "228": 112, "229": 114, "230": 111, "231": 100, "232": 117, "233": 99, "234": 116, "235": 34, "236": 44, "237": 34, "238": 100, "239": 97, "240": 116, "241": 97, "242": 34, "243": 58, "244": 123, "245": 34, "246": 105, "247": 100, "248": 34, "249": 58, "250": 34, "251": 101, "252": 114, "253": 115, "254": 34, "255": 44, "256": 34, "257": 110, "258": 97, "259": 109, "260": 101, "261": 34, "262": 58, "263": 34, "264": 69, "265": 118, "266": 101, "267": 114, "268": 121, "269": 100, "270": 97, "271": 121, "272": 32, "273": 82, "274": 117, "275": 99, "276": 107, "277": 32, "278": 83, "279": 110, "280": 97, "281": 99, "282": 107, "283": 34, "284": 44, "285": 34, "286": 99, "287": 111, "288": 108, "289": 111, "290": 114, "291": 34, "292": 58, "293": 34, "294": 98, "295": 108, "296": 97, "297": 99, "298": 107, "299": 34, "300": 44, "301": 34, "302": 115, "303": 105, "304": 122, "305": 101, "306": 34, "307": 58, "308": 34, "309": 108, "310": 34, "311": 44, "312": 34, "313": 112, "314": 114, "315": 105, "316": 99, "317": 101, "318": 34, "319": 58, "320": 52, "321": 50, "322": 48, "323": 125, "324": 44, "325": 34, "326": 99, "327": 111, "328": 110, "329": 116, "330": 101, "331": 120, "332": 116, "333": 34, "334": 58, "335": 123, "336": 34, "337": 115, "338": 104, "339": 111, "340": 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67, "428": 97, "429": 112, "430": 34, "431": 44, "432": 34, "433": 115, "434": 105, "435": 122, "436": 101, "437": 34, "438": 58, "439": 34, "440": 111, "441": 110, "442": 101, "443": 32, "444": 115, "445": 105, "446": 122, "447": 101, "448": 34, "449": 44, "450": 34, "451": 112, "452": 114, "453": 105, "454": 99, "455": 101, "456": 34, "457": 58, "458": 52, "459": 50, "460": 125, "461": 44, "462": 34, "463": 99, "464": 111, "465": 110, "466": 116, "467": 101, "468": 120, "469": 116, "470": 34, "471": 58, "472": 123, "473": 34, "474": 115, "475": 104, "476": 111, "477": 112, "478": 112, "479": 105, "480": 110, "481": 103, "482": 34, "483": 58, "484": 91, "485": 34, "486": 99, "487": 111, "488": 109, "489": 112, "490": 108, "491": 101, "492": 116, "493": 101, "494": 34, "495": 44, "496": 48, "497": 93, "498": 125, "499": 44, "500": 34, "501": 110, "502": 101, "503": 115, "504": 116, "505": 101, "506": 100, "507": 34, "508": 58, "509": 91, "510": 93, "511": 125, "512": 44, "513": 123, "514": 34, "515": 101, "516": 110, "517": 116, "518": 105, "519": 116, "520": 121, "521": 34, "522": 58, "523": 34, "524": 103, "525": 105, "526": 102, "527": 116, "528": 34, "529": 44, "530": 34, "531": 100, "532": 97, "533": 116, "534": 97, "535": 34, "536": 58, "537": 123, "538": 34, "539": 110, "540": 97, "541": 109, "542": 101, "543": 34, "544": 58, "545": 34, "546": 83, "547": 117, "548": 114, "549": 112, "550": 114, "551": 105, "552": 115, "553": 101, "554": 34, "555": 125, "556": 44, "557": 34, "558": 99, "559": 111, "560": 110, "561": 116, "562": 101, "563": 120, "564": 116, "565": 34, "566": 58, "567": 123, "568": 34, "569": 115, "570": 104, "571": 111, "572": 112, "573": 112, "574": 105, "575": 110, "576": 103, "577": 34, "578": 58, "579": 91, "580": 34, "581": 99, "582": 111, "583": 109, "584": 112, "585": 108, "586": 101, "587": 116, "588": 101, "589": 34, "590": 44, "591": 48, "592": 93, "593": 125, "594": 44, "595": 34, "596": 110, "597": 101, "598": 115, "599": 116, "600": 101, "601": 100, "602": 34, "603": 58, "604": 91, "605": 93, "606": 125, "607": 93, "608": 44, "609": 34, "610": 99, "611": 111, "612": 110, "613": 115, "614": 101, "615": 110, "616": 116, "617": 34, "618": 58, "619": 123, "620": 34, "621": 102, "622": 117, "623": 110, "624": 99, "625": 116, "626": 105, "627": 111, "628": 110, "629": 97, "630": 108, "631": 34, "632": 58, "633": 116, "634": 114, "635": 117, "636": 101, "637": 125, "638": 44, "639": 34, "640": 105, "641": 100, "642": 34, "643": 58, "644": 34, "645": 53, "646": 50, "647": 53, "648": 57, "649": 55, "650": 100, "651": 53, "652": 50, "653": 54, "654": 57, "655": 54, "656": 55, "657": 57, "658": 51, "659": 54, "660": 57, "661": 34, "662": 44, "663": 34, "664": 116, "665": 114, "666": 105, "667": 103, "668": 103, "669": 101, "670": 114, "671": 34, "672": 58, "673": 34, "674": 108, "675": 111, "676": 97, "677": 100, "678": 34, "679": 44, "680": 34, "681": 101, "682": 110, "683": 116, "684": 105, "685": 116, "686": 121, "687": 34, "688": 58, "689": 34, "690": 111, "691": 114, "692": 100, "693": 101, "694": 114, "695": 34, "696": 44, "697": 34, "698": 97, "699": 99, "700": 116, "701": 105, "702": 111, "703": 110, "704": 34, "705": 58, "706": 34, "707": 99, "708": 111, "709": 109, "710": 112, "711": 108, "712": 101, "713": 116, "714": 101, "715": 34, "716": 44, "717": 34, "718": 116, "719": 105, "720": 109, "721": 101, "722": 115, "723": 116, "724": 97, "725": 109, "726": 112, "727": 34, "728": 58, "729": 49, "730": 55, "731": 48, "732": 48, "733": 48, "734": 48, "735": 49, "736": 49, "737": 48, "738": 48, "739": 44, "740": 34, "741": 116, "742": 105, "743": 109, "744": 105, "745": 110, "746": 103, "747": 34, "748": 58, "749": 51, "750": 46, "751": 49, "752": 52, "753": 44, "754": 34, "755": 115, "756": 111, "757": 117, "758": 114, "759": 99, "760": 101, "761": 34, "762": 58, "763": 123, "764": 34, "765": 99, "766": 111, "767": 117, "768": 110, "769": 116, "770": 34, "771": 58, "772": 49, "773": 44, "774": 34, "775": 116, "776": 114, "777": 97, "778": 99, "779": 101, "780": 34, "781": 58, "782": 34, "783": 49, "784": 97, "785": 50, "786": 98, "787": 51, "788": 99, "789": 52, "790": 100, "791": 53, "792": 101, "793": 54, "794": 102, "795": 55, "796": 48, "797": 56, "798": 49, "799": 57, "800": 97, "801": 50, "802": 98, "803": 51, "804": 99, "805": 52, "806": 100, "807": 53, "808": 101, "809": 54, "810": 102, "811": 55, "812": 48, "813": 56, "814": 49, "815": 34, "816": 44, "817": 34, "818": 116, "819": 121, "820": 112, "821": 101, "822": 34, "823": 58, "824": 34, "825": 101, "826": 120, "827": 112, "828": 114, "829": 101, "830": 115, "831": 115, "832": 34, "833": 44, "834": 34, "835": 112, "836": 108, "837": 97, "838": 116, "839": 102, "840": 111, "841": 114, "842": 109, "843": 34, "844": 58, "845": 34, "846": 115, "847": 101, "848": 114, "849": 118, "850": 101, "851": 114, "852": 34, "853": 44, "854": 34, "855": 114, "856": 101, "857": 108, "858": 101, "859": 97, "860": 115, "861": 101, "862": 34, "863": 58, "864": 123, "865": 34, "866": 115, "867": 101, "868": 114, "869": 118, "870": 101, "871": 114, "872": 34, "873": 58, "874": 34, "875": 52, "876": 46, "877": 56, "878": 46, "879": 48, "880": 34, "881": 125, "882": 125, "883": 125 }, "orderingKey": "usr-789" }) ``` ### Topic override A mapping rule overrides the destination default topic so order events are published to a dedicated topic. Event ```json { "name": "order complete", "data": { "id": "ORD-500", "total": 199.99, "currency": "EUR" }, "context": { "shopping": [ "complete", 0 ] }, "globals": { "pagegroup": "shop" }, "custom": { "completely": "random" }, "user": { "id": "usr-789" }, "nested": [ { "entity": "product", "data": { "id": "ers", "name": "Everyday Ruck Snack", "color": "black", "size": "l", "price": 420 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "product", "data": { "id": "cc", "name": "Cool Cap", "size": "one size", "price": 42 }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] }, { "entity": "gift", "data": { "name": "Surprise" }, "context": { "shopping": [ "complete", 0 ] }, "nested": [] } ], "consent": { "functional": true }, "id": "52597d5269679369", "trigger": "load", "entity": "order", "action": "complete", "timestamp": 1700001100, "timing": 3.14, "source": { "count": 1, "trace": "1a2b3c4d5e6f70819a2b3c4d5e6f7081", "type": "express", "platform": "server" } } ``` Mapping ```json { "settings": { "topic": "orders" } } ``` Out ```javascript topic("orders", { "messageOrdering": false }); publishMessage("orders", { "data": { "0": 123, "1": 34, "2": 110, "3": 97, "4": 109, "5": 101, "6": 34, "7": 58, "8": 34, "9": 111, "10": 114, "11": 100, "12": 101, "13": 114, "14": 32, "15": 99, "16": 111, "17": 109, "18": 112, "19": 108, "20": 101, "21": 116, "22": 101, "23": 34, "24": 44, "25": 34, "26": 100, "27": 97, "28": 116, "29": 97, "30": 34, "31": 58, "32": 123, "33": 34, "34": 105, "35": 100, "36": 34, "37": 58, "38": 34, "39": 79, "40": 82, "41": 68, "42": 45, "43": 53, "44": 48, "45": 48, "46": 34, "47": 44, "48": 34, "49": 116, "50": 111, "51": 116, "52": 97, "53": 108, "54": 34, "55": 58, "56": 49, "57": 57, "58": 57, "59": 46, "60": 57, "61": 57, "62": 44, "63": 34, "64": 99, "65": 117, "66": 114, "67": 114, "68": 101, "69": 110, "70": 99, "71": 121, "72": 34, "73": 58, "74": 34, "75": 69, "76": 85, "77": 82, "78": 34, "79": 125, "80": 44, "81": 34, "82": 99, "83": 111, "84": 110, "85": 116, "86": 101, "87": 120, "88": 116, "89": 34, "90": 58, "91": 123, "92": 34, "93": 115, "94": 104, "95": 111, "96": 112, "97": 112, "98": 105, "99": 110, "100": 103, "101": 34, "102": 58, "103": 91, "104": 34, "105": 99, "106": 111, "107": 109, "108": 112, "109": 108, "110": 101, "111": 116, "112": 101, "113": 34, "114": 44, "115": 48, "116": 93, "117": 125, "118": 44, "119": 34, "120": 103, "121": 108, "122": 111, "123": 98, "124": 97, "125": 108, "126": 115, "127": 34, "128": 58, "129": 123, "130": 34, "131": 112, "132": 97, "133": 103, "134": 101, "135": 103, "136": 114, "137": 111, "138": 117, "139": 112, "140": 34, "141": 58, "142": 34, "143": 115, "144": 104, "145": 111, "146": 112, "147": 34, "148": 125, "149": 44, "150": 34, "151": 99, "152": 117, "153": 115, "154": 116, "155": 111, "156": 109, "157": 34, "158": 58, "159": 123, "160": 34, "161": 99, "162": 111, "163": 109, "164": 112, "165": 108, "166": 101, "167": 116, "168": 101, "169": 108, "170": 121, "171": 34, "172": 58, "173": 34, "174": 114, "175": 97, "176": 110, "177": 100, "178": 111, "179": 109, "180": 34, "181": 125, "182": 44, "183": 34, "184": 117, "185": 115, "186": 101, "187": 114, "188": 34, "189": 58, "190": 123, "191": 34, "192": 105, "193": 100, "194": 34, "195": 58, "196": 34, "197": 117, "198": 115, "199": 114, "200": 45, "201": 55, "202": 56, "203": 57, "204": 34, "205": 125, "206": 44, "207": 34, "208": 110, "209": 101, "210": 115, "211": 116, "212": 101, "213": 100, "214": 34, "215": 58, "216": 91, "217": 123, "218": 34, "219": 101, "220": 110, "221": 116, "222": 105, "223": 116, "224": 121, "225": 34, "226": 58, "227": 34, "228": 112, "229": 114, "230": 111, "231": 100, "232": 117, "233": 99, "234": 116, "235": 34, "236": 44, "237": 34, "238": 100, "239": 97, "240": 116, "241": 97, "242": 34, "243": 58, "244": 123, "245": 34, "246": 105, "247": 100, "248": 34, "249": 58, "250": 34, "251": 101, "252": 114, "253": 115, "254": 34, "255": 44, "256": 34, "257": 110, "258": 97, "259": 109, "260": 101, "261": 34, "262": 58, "263": 34, "264": 69, "265": 118, "266": 101, "267": 114, "268": 121, "269": 100, "270": 97, "271": 121, "272": 32, "273": 82, "274": 117, "275": 99, "276": 107, "277": 32, "278": 83, "279": 110, "280": 97, "281": 99, "282": 107, "283": 34, "284": 44, "285": 34, "286": 99, "287": 111, "288": 108, "289": 111, "290": 114, "291": 34, "292": 58, "293": 34, "294": 98, "295": 108, "296": 97, "297": 99, "298": 107, "299": 34, "300": 44, "301": 34, "302": 115, "303": 105, "304": 122, "305": 101, "306": 34, "307": 58, "308": 34, "309": 108, "310": 34, "311": 44, "312": 34, "313": 112, "314": 114, "315": 105, "316": 99, "317": 101, "318": 34, "319": 58, "320": 52, "321": 50, "322": 48, "323": 125, "324": 44, "325": 34, "326": 99, "327": 111, "328": 110, "329": 116, "330": 101, "331": 120, "332": 116, "333": 34, "334": 58, "335": 123, "336": 34, "337": 115, "338": 104, "339": 111, "340": 112, "341": 112, "342": 105, "343": 110, "344": 103, "345": 34, "346": 58, "347": 91, "348": 34, "349": 99, "350": 111, "351": 109, "352": 112, "353": 108, "354": 101, "355": 116, "356": 101, "357": 34, "358": 44, "359": 48, "360": 93, "361": 125, "362": 44, "363": 34, "364": 110, "365": 101, "366": 115, "367": 116, "368": 101, "369": 100, "370": 34, "371": 58, "372": 91, "373": 93, "374": 125, "375": 44, "376": 123, "377": 34, "378": 101, "379": 110, "380": 116, "381": 105, "382": 116, "383": 121, "384": 34, "385": 58, "386": 34, "387": 112, "388": 114, "389": 111, "390": 100, "391": 117, "392": 99, "393": 116, "394": 34, "395": 44, "396": 34, "397": 100, "398": 97, "399": 116, "400": 97, "401": 34, "402": 58, "403": 123, "404": 34, "405": 105, "406": 100, "407": 34, "408": 58, "409": 34, "410": 99, "411": 99, "412": 34, "413": 44, "414": 34, "415": 110, "416": 97, "417": 109, "418": 101, "419": 34, "420": 58, "421": 34, "422": 67, "423": 111, "424": 111, "425": 108, "426": 32, "427": 67, "428": 97, "429": 112, "430": 34, "431": 44, "432": 34, "433": 115, "434": 105, "435": 122, "436": 101, "437": 34, "438": 58, "439": 34, "440": 111, "441": 110, "442": 101, "443": 32, "444": 115, "445": 105, "446": 122, "447": 101, "448": 34, "449": 44, "450": 34, "451": 112, "452": 114, "453": 105, "454": 99, "455": 101, "456": 34, "457": 58, "458": 52, "459": 50, "460": 125, "461": 44, "462": 34, "463": 99, "464": 111, "465": 110, "466": 116, "467": 101, "468": 120, "469": 116, "470": 34, "471": 58, "472": 123, "473": 34, "474": 115, "475": 104, "476": 111, "477": 112, "478": 112, "479": 105, "480": 110, "481": 103, "482": 34, "483": 58, "484": 91, "485": 34, "486": 99, "487": 111, "488": 109, "489": 112, "490": 108, "491": 101, "492": 116, "493": 101, "494": 34, "495": 44, "496": 48, "497": 93, "498": 125, "499": 44, "500": 34, "501": 110, "502": 101, "503": 115, "504": 116, "505": 101, "506": 100, "507": 34, "508": 58, "509": 91, "510": 93, "511": 125, "512": 44, "513": 123, "514": 34, "515": 101, "516": 110, "517": 116, "518": 105, "519": 116, "520": 121, "521": 34, "522": 58, "523": 34, "524": 103, "525": 105, "526": 102, "527": 116, "528": 34, "529": 44, "530": 34, "531": 100, "532": 97, "533": 116, "534": 97, "535": 34, "536": 58, "537": 123, "538": 34, "539": 110, "540": 97, "541": 109, "542": 101, "543": 34, "544": 58, "545": 34, "546": 83, "547": 117, "548": 114, "549": 112, "550": 114, "551": 105, "552": 115, "553": 101, "554": 34, "555": 125, "556": 44, "557": 34, "558": 99, "559": 111, "560": 110, "561": 116, "562": 101, "563": 120, "564": 116, "565": 34, "566": 58, "567": 123, "568": 34, "569": 115, "570": 104, "571": 111, "572": 112, "573": 112, "574": 105, "575": 110, "576": 103, "577": 34, "578": 58, "579": 91, "580": 34, "581": 99, "582": 111, "583": 109, "584": 112, "585": 108, "586": 101, "587": 116, "588": 101, "589": 34, "590": 44, "591": 48, "592": 93, "593": 125, "594": 44, "595": 34, "596": 110, "597": 101, "598": 115, "599": 116, "600": 101, "601": 100, "602": 34, "603": 58, "604": 91, "605": 93, "606": 125, "607": 93, "608": 44, "609": 34, "610": 99, "611": 111, "612": 110, "613": 115, "614": 101, "615": 110, "616": 116, "617": 34, "618": 58, "619": 123, "620": 34, "621": 102, "622": 117, "623": 110, "624": 99, "625": 116, "626": 105, "627": 111, "628": 110, "629": 97, "630": 108, "631": 34, "632": 58, "633": 116, "634": 114, "635": 117, "636": 101, "637": 125, "638": 44, "639": 34, "640": 105, "641": 100, "642": 34, "643": 58, "644": 34, "645": 53, "646": 50, "647": 53, "648": 57, "649": 55, "650": 100, "651": 53, "652": 50, "653": 54, "654": 57, "655": 54, "656": 55, "657": 57, "658": 51, "659": 54, "660": 57, "661": 34, "662": 44, "663": 34, "664": 116, "665": 114, "666": 105, "667": 103, "668": 103, "669": 101, "670": 114, "671": 34, "672": 58, "673": 34, "674": 108, "675": 111, "676": 97, "677": 100, "678": 34, "679": 44, "680": 34, "681": 101, "682": 110, "683": 116, "684": 105, "685": 116, "686": 121, "687": 34, "688": 58, "689": 34, "690": 111, "691": 114, "692": 100, "693": 101, "694": 114, "695": 34, "696": 44, "697": 34, "698": 97, "699": 99, "700": 116, "701": 105, "702": 111, "703": 110, "704": 34, "705": 58, "706": 34, "707": 99, "708": 111, "709": 109, "710": 112, "711": 108, "712": 101, "713": 116, "714": 101, "715": 34, "716": 44, "717": 34, "718": 116, "719": 105, "720": 109, "721": 101, "722": 115, "723": 116, "724": 97, "725": 109, "726": 112, "727": 34, "728": 58, "729": 49, "730": 55, "731": 48, "732": 48, "733": 48, "734": 48, "735": 49, "736": 49, "737": 48, "738": 48, "739": 44, "740": 34, "741": 116, "742": 105, "743": 109, "744": 105, "745": 110, "746": 103, "747": 34, "748": 58, "749": 51, "750": 46, "751": 49, "752": 52, "753": 44, "754": 34, "755": 115, "756": 111, "757": 117, "758": 114, "759": 99, "760": 101, "761": 34, "762": 58, "763": 123, "764": 34, "765": 99, "766": 111, "767": 117, "768": 110, "769": 116, "770": 34, "771": 58, "772": 49, "773": 44, "774": 34, "775": 116, "776": 114, "777": 97, "778": 99, "779": 101, "780": 34, "781": 58, "782": 34, "783": 49, "784": 97, "785": 50, "786": 98, "787": 51, "788": 99, "789": 52, "790": 100, "791": 53, "792": 101, "793": 54, "794": 102, "795": 55, "796": 48, "797": 56, "798": 49, "799": 57, "800": 97, "801": 50, "802": 98, "803": 51, "804": 99, "805": 52, "806": 100, "807": 53, "808": 101, "809": 54, "810": 102, "811": 55, "812": 48, "813": 56, "814": 49, "815": 34, "816": 44, "817": 34, "818": 116, "819": 121, "820": 112, "821": 101, "822": 34, "823": 58, "824": 34, "825": 101, "826": 120, "827": 112, "828": 114, "829": 101, "830": 115, "831": 115, "832": 34, "833": 44, "834": 34, "835": 112, "836": 108, "837": 97, "838": 116, "839": 102, "840": 111, "841": 114, "842": 109, "843": 34, "844": 58, "845": 34, "846": 115, "847": 101, "848": 114, "849": 118, "850": 101, "851": 114, "852": 34, "853": 44, "854": 34, "855": 114, "856": 101, "857": 108, "858": 101, "859": 97, "860": 115, "861": 101, "862": 34, "863": 58, "864": 123, "865": 34, "866": 115, "867": 101, "868": 114, "869": 118, "870": 101, "871": 114, "872": 34, "873": 58, "874": 34, "875": 52, "876": 46, "877": 56, "878": 46, "879": 48, "880": 34, "881": 125, "882": 125, "883": 125 } }) ``` ### Page view A page view is published to the default topic with no ordering key, demonstrating the simplest publish path. Event ```json { "name": "page view", "data": { "title": "Documentation", "url": "https://example.com/docs" }, "context": { "dev": [ "test", 1 ] }, "globals": { "pagegroup": "docs" }, "custom": { "completely": "random" }, "user": { "id": "us3r", "device": "c00k13", "session": "s3ss10n" }, "nested": [ { "entity": "child", "data": { "is": "subordinated" } } ], "consent": { "functional": true }, "id": "408ff7a6af540165", "trigger": "load", "entity": "page", "action": "view", "timestamp": 1700001101, "timing": 3.14, "source": { "count": 1, "trace": "9f8e7d6c5b4a39281706f5e4d3c2b1a0", "type": "express", "platform": "server" } } ``` Out ```javascript topic("events", { "messageOrdering": false }); publishMessage("events", { "data": { "0": 123, "1": 34, "2": 110, "3": 97, "4": 109, "5": 101, "6": 34, "7": 58, "8": 34, "9": 112, "10": 97, "11": 103, "12": 101, "13": 32, "14": 118, "15": 105, "16": 101, "17": 119, "18": 34, "19": 44, "20": 34, "21": 100, "22": 97, "23": 116, "24": 97, "25": 34, "26": 58, "27": 123, "28": 34, "29": 116, "30": 105, "31": 116, "32": 108, "33": 101, "34": 34, "35": 58, "36": 34, "37": 68, "38": 111, "39": 99, "40": 117, "41": 109, "42": 101, "43": 110, "44": 116, "45": 97, "46": 116, "47": 105, "48": 111, "49": 110, "50": 34, "51": 44, "52": 34, "53": 117, "54": 114, "55": 108, "56": 34, "57": 58, "58": 34, "59": 104, "60": 116, "61": 116, "62": 112, "63": 115, "64": 58, "65": 47, "66": 47, "67": 101, "68": 120, "69": 97, "70": 109, "71": 112, "72": 108, "73": 101, "74": 46, "75": 99, "76": 111, "77": 109, "78": 47, "79": 100, "80": 111, "81": 99, "82": 115, "83": 34, "84": 125, "85": 44, "86": 34, "87": 99, "88": 111, "89": 110, "90": 116, "91": 101, "92": 120, "93": 116, "94": 34, "95": 58, "96": 123, "97": 34, "98": 100, "99": 101, "100": 118, "101": 34, "102": 58, "103": 91, "104": 34, "105": 116, "106": 101, "107": 115, "108": 116, "109": 34, "110": 44, "111": 49, "112": 93, "113": 125, "114": 44, "115": 34, "116": 103, "117": 108, "118": 111, "119": 98, "120": 97, "121": 108, "122": 115, "123": 34, "124": 58, "125": 123, "126": 34, "127": 112, "128": 97, "129": 103, "130": 101, "131": 103, "132": 114, "133": 111, "134": 117, "135": 112, "136": 34, "137": 58, "138": 34, "139": 100, "140": 111, "141": 99, "142": 115, "143": 34, "144": 125, "145": 44, "146": 34, "147": 99, "148": 117, "149": 115, "150": 116, "151": 111, "152": 109, "153": 34, "154": 58, "155": 123, "156": 34, "157": 99, "158": 111, "159": 109, "160": 112, "161": 108, "162": 101, "163": 116, "164": 101, "165": 108, "166": 121, "167": 34, "168": 58, "169": 34, "170": 114, "171": 97, "172": 110, "173": 100, "174": 111, "175": 109, "176": 34, "177": 125, "178": 44, "179": 34, "180": 117, "181": 115, "182": 101, "183": 114, "184": 34, "185": 58, "186": 123, "187": 34, "188": 105, "189": 100, "190": 34, "191": 58, "192": 34, "193": 117, "194": 115, "195": 51, "196": 114, "197": 34, "198": 44, "199": 34, "200": 100, "201": 101, "202": 118, "203": 105, "204": 99, "205": 101, "206": 34, "207": 58, "208": 34, "209": 99, "210": 48, "211": 48, "212": 107, "213": 49, "214": 51, "215": 34, "216": 44, "217": 34, "218": 115, "219": 101, "220": 115, "221": 115, "222": 105, "223": 111, "224": 110, "225": 34, "226": 58, "227": 34, "228": 115, "229": 51, "230": 115, "231": 115, "232": 49, "233": 48, "234": 110, "235": 34, "236": 125, "237": 44, "238": 34, "239": 110, "240": 101, "241": 115, "242": 116, "243": 101, "244": 100, "245": 34, "246": 58, "247": 91, "248": 123, "249": 34, "250": 101, "251": 110, "252": 116, "253": 105, "254": 116, "255": 121, "256": 34, "257": 58, "258": 34, "259": 99, "260": 104, "261": 105, "262": 108, "263": 100, "264": 34, "265": 44, "266": 34, "267": 100, "268": 97, "269": 116, "270": 97, "271": 34, "272": 58, "273": 123, "274": 34, "275": 105, "276": 115, "277": 34, "278": 58, "279": 34, "280": 115, "281": 117, "282": 98, "283": 111, "284": 114, "285": 100, "286": 105, "287": 110, "288": 97, "289": 116, "290": 101, "291": 100, "292": 34, "293": 125, "294": 125, "295": 93, "296": 44, "297": 34, "298": 99, "299": 111, "300": 110, "301": 115, "302": 101, "303": 110, "304": 116, "305": 34, "306": 58, "307": 123, "308": 34, "309": 102, "310": 117, "311": 110, "312": 99, "313": 116, "314": 105, "315": 111, "316": 110, "317": 97, "318": 108, "319": 34, "320": 58, "321": 116, "322": 114, "323": 117, "324": 101, "325": 125, "326": 44, "327": 34, "328": 105, "329": 100, "330": 34, "331": 58, "332": 34, "333": 52, "334": 48, "335": 56, "336": 102, "337": 102, "338": 55, "339": 97, "340": 54, "341": 97, "342": 102, "343": 53, "344": 52, "345": 48, "346": 49, "347": 54, "348": 53, "349": 34, "350": 44, "351": 34, "352": 116, "353": 114, "354": 105, "355": 103, "356": 103, "357": 101, "358": 114, "359": 34, "360": 58, "361": 34, "362": 108, "363": 111, "364": 97, "365": 100, "366": 34, "367": 44, "368": 34, "369": 101, "370": 110, "371": 116, "372": 105, "373": 116, "374": 121, "375": 34, "376": 58, "377": 34, "378": 112, "379": 97, "380": 103, "381": 101, "382": 34, "383": 44, "384": 34, "385": 97, "386": 99, "387": 116, "388": 105, "389": 111, "390": 110, "391": 34, "392": 58, "393": 34, "394": 118, "395": 105, "396": 101, "397": 119, "398": 34, "399": 44, "400": 34, "401": 116, "402": 105, "403": 109, "404": 101, "405": 115, "406": 116, "407": 97, "408": 109, "409": 112, "410": 34, "411": 58, "412": 49, "413": 55, "414": 48, "415": 48, "416": 48, "417": 48, "418": 49, "419": 49, "420": 48, "421": 49, "422": 44, "423": 34, "424": 116, "425": 105, "426": 109, "427": 105, "428": 110, "429": 103, "430": 34, "431": 58, "432": 51, "433": 46, "434": 49, "435": 52, "436": 44, "437": 34, "438": 115, "439": 111, "440": 117, "441": 114, "442": 99, "443": 101, "444": 34, "445": 58, "446": 123, "447": 34, "448": 99, "449": 111, "450": 117, "451": 110, "452": 116, "453": 34, "454": 58, "455": 49, "456": 44, "457": 34, "458": 116, "459": 114, "460": 97, "461": 99, "462": 101, "463": 34, "464": 58, "465": 34, "466": 57, "467": 102, "468": 56, "469": 101, "470": 55, "471": 100, "472": 54, "473": 99, "474": 53, "475": 98, "476": 52, "477": 97, "478": 51, "479": 57, "480": 50, "481": 56, "482": 49, "483": 55, "484": 48, "485": 54, "486": 102, "487": 53, "488": 101, "489": 52, "490": 100, "491": 51, "492": 99, "493": 50, "494": 98, "495": 49, "496": 97, "497": 48, "498": 34, "499": 44, "500": 34, "501": 116, "502": 121, "503": 112, "504": 101, "505": 34, "506": 58, "507": 34, "508": 101, "509": 120, "510": 112, "511": 114, "512": 101, "513": 115, "514": 115, "515": 34, "516": 44, "517": 34, "518": 112, "519": 108, "520": 97, "521": 116, "522": 102, "523": 111, "524": 114, "525": 109, "526": 34, "527": 58, "528": 34, "529": 115, "530": 101, "531": 114, "532": 118, "533": 101, "534": 114, "535": 34, "536": 44, "537": 34, "538": 114, "539": 101, "540": 108, "541": 101, "542": 97, "543": 115, "544": 101, "545": 34, "546": 58, "547": 123, "548": 34, "549": 115, "550": 101, "551": 114, "552": 118, "553": 101, "554": 114, "555": 34, "556": 58, "557": 34, "558": 52, "559": 46, "560": 56, "561": 46, "562": 48, "563": 34, "564": 125, "565": 125, "566": 125 } }) ``` ## Authentication[​](#authentication "Direct link to Authentication") Three modes, evaluated in order: 1. **Application Default Credentials (ADC).** Nothing to configure beyond `projectId`. Works on GCP-native runtimes (Cloud Run, Cloud Functions, GKE, GCE) where the runtime service account is attached, and locally with `gcloud auth application-default login`. 2. **Service account JSON.** Pass credentials via `config.credentials`, either as a parsed object or a JSON string (the destination JSON-parses strings). Pair with `$env.NAME` to inject from an environment variable. (The package-specific `settings.credentials` still works but is deprecated.) 3. **Pre-configured client.** Pass an existing `PubSub` SDK instance as `settings.client`. Useful for shared clients across destinations or custom transport configuration. When `settings.projectId` and the credentials' `project_id` both resolve, the top-level `settings.projectId` wins. The runtime publish target stays unambiguous. ## Ordering[​](#ordering "Direct link to Ordering") `orderingKey` is a `Mapping.Value` resolved per event. Truthy resolved values enable per-key ordering, the topic handle is constructed with `messageOrdering: true`, and the resolved key flows on the publish. ``` { "settings": { "projectId": "my-project", "topic": "user-events", "orderingKey": "user.id" } } ``` Per-rule overrides live under `mapping...settings.orderingKey`. If a publish fails for an ordered key, Pub/Sub permanently halts subsequent publishes for that key until `topic.resumePublishing(key)` is called. The destination handles this automatically: on publish failure for an ordered key it calls `resumePublishing` immediately and re-throws so the caller observes the original error. ## Attributes[​](#attributes "Direct link to Attributes") `settings.attributes` is a `Mapping.Map` of attribute name to mapping value. Each value is resolved per event and stringified. Per-rule overrides under `mapping...settings.attributes` are merged onto the defaults. ``` { "settings": { "projectId": "my-project", "topic": "events", "attributes": { "tenant": "user.tenant_id", "schema_version": { "value": "v4" } } } } ``` ## Setup[​](#setup "Direct link to Setup") Provision the topic once per environment: ```bash walkeros setup destination.pubsub ``` Idempotent: re-running on an existing topic logs `setup: topic exists` and runs drift detection. Drift on `messageStoragePolicy.allowedPersistenceRegions`, `messageRetentionDuration`, `kmsKeyName`, or `labels` emits `WARN setup.drift {...}` and never auto-mutates. Migrations are an operator decision. `config.setup`: * `false` (default): no provisioning. Operator must run setup explicitly. * `true`: provisions with safe defaults (EU multi-region storage policy). * `{ messageStoragePolicy, messageRetentionDuration, kmsKeyName, labels }`: object form for explicit overrides. Default storage regions: `['europe-west1', 'europe-west3', 'europe-west4']` (EU multi-region). Override `messageStoragePolicy.allowedPersistenceRegions` for projects with org policies that restrict geography. The provisioning identity needs `pubsub.topics.create` and `pubsub.topics.get` on the project. The runtime publish identity needs `roles/pubsub.publisher` on the topic itself. Subscription provisioning is owned by the [Pub/Sub source](/preview/pr-749/docs/sources/server/pubsub.md), not this destination. ## Emulator[​](#emulator "Direct link to Emulator") The official Pub/Sub emulator runs locally for development: ```bash gcloud beta emulators pubsub start --host-port=localhost:8085 export PUBSUB_EMULATOR_HOST=localhost:8085 ``` The SDK automatically picks up `PUBSUB_EMULATOR_HOST`. For explicit configuration, set `settings.apiEndpoint` (e.g. `localhost:8085`). ## Simulate[​](#simulate "Direct link to Simulate") `walkeros push --simulate destination.pubsub` runs offline with the package's mock Pub/Sub client and prints the publish it would make; nothing reaches GCP. The step's `import` (`destinationPubSub`) selects the Pub/Sub examples and mock, not BigQuery's. ```text success: true destination.pubsub mapping: none call PubSub.topic.publishMessage({"data":"{\"name\":\"order complete\",...}"}) ``` ## Troubleshooting[​](#troubleshooting "Direct link to Troubleshooting") * **`NOT_FOUND` on publish**: the topic does not exist. Run `walkeros setup destination.` once. * **`PERMISSION_DENIED` / `UNAUTHENTICATED`**: the runtime service account lacks `roles/pubsub.publisher` on the topic, or ADC is not configured. The destination logs the actionable message including the topic and project IDs. * **Ordering stuck**: a previous publish for an ordering key failed. The destination calls `resumePublishing` automatically; if stalls persist, check publish-side error logs for the original failure. ## Next steps[​](#next-steps "Direct link to Next steps") * [Pub/Sub source](/preview/pr-749/docs/sources/server/pubsub.md) for consuming events from a Pub/Sub topic * [GCP package overview](/preview/pr-749/docs/destinations/server/gcp.md) for BigQuery and shared GCP setup