Function startCluster

t/t.go:228–323

(composeFile, prefix string)

}

func startCluster(composeFile, prefix string) error {
	ensureGoPathLinuxBinEnvVarSet()

	if os.Getenv("GOPATH") == "" {
		return fmt.Errorf("GOPATH environment variable is required but not set")
	}

	if err := ensureDgraphLinuxBinary(); err != nil {
		return err
	}
	// + --project-directory so relative bind-mount sources resolve against the
	// pristine test package dir.
	composeArgs := ComposeFileArgs(composeFile, *baseDir)
	upArgs := append([]string{"docker", "compose", "--compatibility"},
		append(composeArgs, "-p", prefix, "up", "--force-recreate", "--build", "--remove-orphans", "--detach")...)

	// docker compose `up` on a shared named volume can race on initial
	// volume population when multiple containers using the same volume
	// start concurrently ("failed to mkdir .../_data/<entry>: file exists").
	// Retry once after a full `down -v` — the second attempt finds a fresh
	// volume and succeeds. One retry is enough in practice for this class
	// of race; anything persistent is a real configuration error.
	const upAttempts = 3
	var lastErr error
	var cmdStderr strings.Builder
	fmt.Printf("Bringing up cluster %s for package: %s ...\n", prefix, composeFile)
	for attempt := 1; attempt <= upAttempts; attempt++ {
		cmdStderr.Reset()
		cmd := command(upArgs...)
		cmd.Stderr = &cmdStderr
		if err := cmd.Run(); err == nil {
			lastErr = nil
			break
		} else {
			lastErr = err
			stderr := cmdStderr.String()
			fmt.Printf("Bring-up attempt %d/%d failed: %v\n", attempt, upAttempts, err)
			if stderr != "" {
				fmt.Printf("docker compose stderr:\n%s\n", stderr)
			}
			if attempt < upAttempts {
				// Tear down any partial state so the retry starts from a
				// clean volume/network baseline. Run `down -v` to remove
				// the volume the next attempt will recreate, then sleep
				// briefly so docker has time to release the mount points
				// before the next `up` tries to populate a fresh volume.
				// Without the sleep, the retry can hit the same volume-
				// init race the first attempt did.
				downArgs := append([]string{"docker", "compose", "--compatibility"},
					append(composeArgs, "-p", prefix, "down", "-v")...)
				downCmd := command(downArgs...)
				downCmd.Stderr = nil
				_ = downCmd.Run()
				time.Sleep(2 * time.Second)
				fmt.Printf("Retrying cluster bring-up (attempt %d/%d) after `down -v`...\n", attempt+1, upAttempts)
			}
		}
	}