Container Port Forwarding

name = "my-app"
main = "src/index.ts"

# Define your containers
[[containers]]
class_name = "ContainerA"
image      = "./containers/a/Dockerfile"
instances  = 3

[[containers]]
class_name = "ContainerB"
image      = "./containers/b/Dockerfile"
instances  = 3

# Containers are backed by Durable Objects
[[durable_objects.bindings]]
class_name = "ContainerA"
name       = "CONTAINER_A"

[[durable_objects.bindings]]
class_name = "ContainerB"
name       = "CONTAINER_B"

import { Container, getContainer } from "@cloudflare/containers";

// Container A - set the port it listens on
export class ContainerA extends Container {
  override port = 8080;  // <-- change this!
}

// Container B - different port
export class ContainerB extends Container {
  override port = 3000;  // <-- change this!
}

export default {
  async fetch(req, env) {
    // Get container instances
    const a = getContainer(env.CONTAINER_A, "a");
    const b = getContainer(env.CONTAINER_B, "b");

    // Forward request from A -> B
    const data = await a.fetch("/get-payload");
    const result = await b.fetch("/receive", {
      method: "POST",
      body: data.body,
    });

    return result;
  },
};

FROM golang:1.22-alpine
WORKDIR /app
COPY . .
RUN go build -o server .

# EXPOSE only needed for local dev
# In production, all ports are auto-accessible
EXPOSE 8080

CMD ["./server"]

package main

import (
    "fmt"
    "net/http"
)

func main() {
    http.HandleFunc("/get-payload", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, `{"event": "ping", "from": "container-a"}`)
    })

    // Listen on the port the Worker expects
    fmt.Println("Container A listening on :8080")
    http.ListenAndServe(":8080", nil)
}