feat: improved deploy progress reporting

See toolshed/abra#478

pkg/logs/logs.go

@@ -0,0 +1,104 @@
+package logs
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+	"sync"
+
+	"github.com/docker/docker/api/types"
+	containerTypes "github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/api/types/filters"
+	dockerClient "github.com/docker/docker/client"
+)
+
+type TailOpts struct {
+	AppName  string
+	Services []string
+	StdErr   bool
+	Since    string
+	Buffer   *[]string
+	ToBuffer bool
+	Filters  filters.Args
+}
+
+// TailLogs gathers logs for the given app with optional service names to be
+// filtered on. These logs can be printed to os.Stdout or gathered to a buffer.
+func TailLogs(
+	cl *dockerClient.Client,
+	opts TailOpts,
+) error {
+	sigIntCh := make(chan os.Signal, 1)
+	signal.Notify(sigIntCh, os.Interrupt)
+	defer signal.Stop(sigIntCh)
+
+	services, err := cl.ServiceList(
+		context.Background(),
+		types.ServiceListOptions{Filters: opts.Filters},
+	)
+	if err != nil {
+		return err
+	}
+
+	errCh := make(chan error)
+	waitCh := make(chan struct{})
+
+	go func() {
+		var wg sync.WaitGroup
+		for _, service := range services {
+			wg.Add(1)
+			go func(serviceID string) {
+				tail := "50"
+				if opts.ToBuffer {
+					// NOTE(d1): more logs from before deployment when analysing via file
+					tail = "150"
+				}
+
+				logs, err := cl.ServiceLogs(context.Background(), serviceID, containerTypes.LogsOptions{
+					ShowStderr: true,
+					ShowStdout: !opts.StdErr,
+					Since:      opts.Since,
+					Until:      "",
+					Timestamps: true,
+					Follow:     true,
+					Tail:       tail,
+					Details:    false,
+				})
+
+				if err == nil {
+					defer logs.Close()
+					if opts.ToBuffer {
+						buf := bufio.NewScanner(logs)
+						for buf.Scan() {
+							line := fmt.Sprintf("%s: %s", service.Spec.Name, buf.Text())
+							*opts.Buffer = append(*opts.Buffer, line)
+						}
+						logs.Close()
+						return
+					}
+
+					if _, err = io.Copy(os.Stdout, logs); err != nil && err != io.EOF {
+						errCh <- fmt.Errorf("tailLogs: unable to copy buffer: %s", err)
+					}
+				}
+			}(service.ID)
+		}
+
+		wg.Wait()
+		close(waitCh)
+	}()
+
+	select {
+	case <-waitCh:
+		return nil
+	case <-sigIntCh:
+		return nil
+	case err := <-errCh:
+		return err
+	}
+
+	return nil
+}