Function ConnectEngineToEngine

engine/client/client.go:350–437

ConnectEngineToEngine connects a Dagger client to another Dagger engine using an existing session connection. Session attachables are proxied back to the original client.

(ctx context.Context, params EngineToEngineParams)

// ConnectEngineToEngine connects a Dagger client to another Dagger engine using an existing session connection.
// Session attachables are proxied back to the original client.
func ConnectEngineToEngine(ctx context.Context, params EngineToEngineParams) (_ *Client, rerr error) {
	loadWorkspaceModules, err := normalizeWorkspaceModuleLoading(
		params.LoadWorkspaceModules,
		params.SkipWorkspaceModules,
	)
	if err != nil {
		return nil, err
	}
	params.LoadWorkspaceModules = loadWorkspaceModules
	params.SkipWorkspaceModules = false

	c := &Client{
		Params:                params.Params,
		isCloudScaleOutClient: true,
	}

	if c.ID == "" {
		c.ID = os.Getenv("DAGGER_SESSION_CLIENT_ID")
	}
	if c.ID == "" {
		c.ID = identity.NewID()
	}
	if c.SessionID == "" {
		c.SessionID = identity.NewID()
	}
	if c.SecretToken == "" {
		c.SecretToken = uuid.New().String()
	}

	// NB: decouple from the originator's cancel ctx
	c.internalCtx, c.internalCancel = context.WithCancelCause(context.WithoutCancel(ctx))
	c.closeCtx, c.closeRequests = context.WithCancelCause(context.WithoutCancel(ctx))

	c.eg, c.internalCtx = errgroup.WithContext(c.internalCtx)

	defer func() {
		if rerr != nil {
			c.internalCancel(errors.New("Connect failed"))
		}
	}()

	c.labels = params.Labels

	hostname, err := os.Hostname()
	if err != nil {
		return nil, fmt.Errorf("get hostname: %w", err)
	}
	c.hostname = hostname

	c.stableClientID = params.StableClientID

	// NB: don't propagate this ctx, we don't want everything tucked beneath connect
	connectCtx, span := Tracer(ctx).Start(ctx, "connect to cloud engine")
	defer telemetry.EndWithCause(span, &rerr)

	if err := c.startEngine(connectCtx, params.Params); err != nil {
		return nil, fmt.Errorf("start engine: %w", err)
	}