Improve log attachment at buildtime

daemon/inertiad/project/build.go

@@ -91,20 +91,10 @@ func dockerCompose(d *Deployment, cli *docker.Client, out io.Writer) (func() err
 	if err != nil {
 		return nil, err
 	}
-
-	// Attach logs and report build progress until container exits
-	reader, err := ContainerLogs(cli, LogOptions{
-		Container: resp.ID, Stream: true,
-		NoTimestamps: true,
-	})
-	if err != nil {
-		return nil, err
-	}
 	stop := make(chan struct{})
-	go log.FlushRoutine(out, reader, stop)
+	go StreamContainerLogs(cli, resp.ID, out, stop)
 	status, err := cli.ContainerWait(ctx, resp.ID)
 	close(stop)
-	reader.Close()
 	if err != nil {
 		return nil, err
 	}
@@ -250,18 +240,10 @@ func herokuishBuild(d *Deployment, cli *docker.Client, out io.Writer) (func() er
 	}
 
 	// Attach logs and report build progress until container exits
-	reader, err := ContainerLogs(cli, LogOptions{
-		Container: resp.ID, Stream: true,
-		NoTimestamps: true,
-	})
-	if err != nil {
-		return nil, err
-	}
 	stop := make(chan struct{})
-	go log.FlushRoutine(out, reader, stop)
+	go StreamContainerLogs(cli, resp.ID, out, stop)
 	status, err := cli.ContainerWait(ctx, resp.ID)
 	close(stop)
-	reader.Close()
 	if err != nil {
 		return nil, err
 	}

daemon/inertiad/project/docker.go

@@ -11,6 +11,7 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
 	docker "github.com/docker/docker/client"
+	"github.com/ubclaunchpad/inertia/daemon/inertiad/log"
 )
 
 var (
@@ -85,3 +86,20 @@ func stopActiveContainers(cli *docker.Client, out io.Writer) error {
 	_, err = cli.ContainersPrune(ctx, filters.Args{})
 	return err
 }
+
+// StreamContainerLogs streams logs from given container ID. Best used as a
+// goroutine.
+func StreamContainerLogs(client *docker.Client, id string, out io.Writer,
+	stop chan struct{}) error {
+	// Attach logs and report build progress until container exits
+	reader, err := ContainerLogs(client, LogOptions{
+		Container: id, Stream: true,
+		NoTimestamps: true,
+	})
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+	log.FlushRoutine(out, reader, stop)
+	return nil
+}