Docker

The walkeros/flow image runs a flow bundle you build with the CLI. This quickstart builds a small collector, runs it in a container, and sends it an event.

You need Docker, Node.js, and network access to npm (the CLI downloads the packages your flow names).

1. Create a flow

Save this as flow.json. The Express source receives events on /collect, and the demo destination logs each event's name and data:

{
  "version": 4,
  "flows": {
    "default": {
      "config": { "platform": "server" },
      "sources": {
        "http": { "package": "@walkeros/server-source-express" }
      },
      "destinations": {
        "demo": {
          "package": "@walkeros/destination-demo",
          "config": { "settings": { "values": ["name", "data"] } }
        }
      }
    }
  }
}

2. Bundle it

npm install -g @walkeros/cli
walkeros bundle flow.json -o dist/

This writes dist/flow.mjs, dist/package.json, and dist/node_modules/. The packages stay in node_modules/, so the container needs the whole directory, not flow.mjs alone.

3. Run the container

Mount the bundle directory at /app/flow, where the image expects flow.mjs:

docker run --rm -p 8080:8080 \
  -v $(pwd)/dist:/app/flow:ro \
  walkeros/flow:latest

The image's entrypoint checks that the bundle file exists before it starts. If it exits with bundle not found, check the mount path.

4. Send an event

In another terminal:

curl -X POST http://localhost:8080/collect \
  -H "Content-Type: application/json" \
  -d '{"name":"page view","data":{"title":"Home"}}'

The response is {"success":true,"timestamp":...}, and the container log shows the event:

[demo] {
  "name": "page view",
  "data": {
    "title": "Home"
  }
}

GET http://localhost:8080/health returns {"status":"ok"} while the container runs.

Build a custom image

Bake the bundle into your own image instead of mounting it:

FROM walkeros/flow:latest
COPY dist/ /app/flow/

docker build -t my-walker .
docker run -p 8080:8080 my-walker

Docker compose

services:
  walkeros:
    image: walkeros/flow:latest
    volumes:
      - ./dist:/app/flow:ro
    ports:
      - '8080:8080'
    restart: unless-stopped

Single-file archive

To ship one file instead of a directory, bundle to an archive and point BUNDLE at it. The runtime extracts it into /app/flow/ at startup, so leave that directory writable:

walkeros bundle flow.json -o flow.tar.gz

docker run --rm -p 8080:8080 \
  -v $(pwd)/flow.tar.gz:/app/bundle/flow.tar.gz:ro \
  -e BUNDLE=/app/bundle/flow.tar.gz \
  walkeros/flow:latest

Environment variables

Variable	Description	Default
BUNDLE	Path inside the container to flow.mjs or a .tar.gz archive	/app/flow/flow.mjs
PORT	Server port	8080

Next steps

• Docker deployment guide
• Runner: remote config, heartbeats, and hot-swap
• Available sources
• Available destinations