✨ Command verbosity.

command/cmd.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"fmt"
 	"os/exec"
-	"strings"
 
 	hub "github.com/konveyor/tackle2-hub/addon"
 )
@@ -17,13 +16,30 @@ var (
 	addon = hub.Addon
 )
 
+//
+// New returns a command.
+func New(path string) (cmd *Command) {
+	cmd = &Command{Path: path}
+	cmd.Reporter.Filter = func(in string) (out string) {
+		out = in
+		return
+	}
+	cmd.Writer.Filter = func(in []byte) (out []byte) {
+		out = in
+		return
+	}
+	return
+}
+
 //
 // Command execution.
 type Command struct {
-	Options Options
-	Path    string
-	Dir     string
-	Output  []byte
+	Verbosity int
+	Options   Options
+	Path      string
+	Dir       string
+	Reporter  Reporter
+	Writer    Writer
 }
 
 //
@@ -40,22 +56,25 @@ func (r *Command) Run() (err error) {
 // The command and output are both reported in
 // task Report.Activity.
 func (r *Command) RunWith(ctx context.Context) (err error) {
-	addon.Activity(
-		"[CMD] Running: %s %s",
-		r.Path,
-		strings.Join(r.Options, " "))
+	r.Writer.reporter = &r.Reporter
+	r.Reporter.Run(r.Path, r.Options)
+	defer func() {
+		r.Writer.End()
+		if err != nil {
+			r.Reporter.Error(r.Path, err, r.Writer.buffer)
+		} else {
+			r.Reporter.Succeeded(r.Path)
+		}
+	}()
 	cmd := exec.CommandContext(ctx, r.Path, r.Options...)
 	cmd.Dir = r.Dir
-	r.Output, err = cmd.CombinedOutput()
+	cmd.Stdout = &r.Writer
+	cmd.Stderr = &r.Writer
+	err = cmd.Start()
 	if err != nil {
-		addon.Activity(
-			"[CMD] %s failed: %s.\n%s",
-			r.Path,
-			err.Error(),
-			string(r.Output))
-	} else {
-		addon.Activity("[CMD] succeeded.")
+		return
 	}
+	err = cmd.Wait()
 	return
 }
 
@@ -64,41 +83,30 @@ func (r *Command) RunWith(ctx context.Context) (err error) {
 // On error: The command (without arguments) and output are
 // reported in task Report.Activity
 func (r *Command) RunSilent() (err error) {
-	err = r.RunSilentWith(context.TODO())
+	r.Reporter.Verbosity = 0
+	err = r.RunWith(context.TODO())
 	return
 }
 
 //
-// RunSilentWith executes the command with context.
-// On error: The command (without arguments) and output are
-// reported in task Report.Activity
-func (r *Command) RunSilentWith(ctx context.Context) (err error) {
-	cmd := exec.CommandContext(ctx, r.Path, r.Options...)
-	cmd.Dir = r.Dir
-	r.Output, err = cmd.CombinedOutput()
-	if err != nil {
-		addon.Activity(
-			"[CMD] %s failed: %s.\n%s",
-			r.Path,
-			err.Error(),
-			string(r.Output))
-	}
-	return
+// Output returns the command output.
+func (r *Command) Output() (b []byte) {
+	return r.Writer.buffer
 }
 
 //
 // Options are CLI options.
 type Options []string
 
 //
-// add
+// Add option.
 func (a *Options) Add(option string, s ...string) {
 	*a = append(*a, option)
 	*a = append(*a, s...)
 }
 
 //
-// add
+// Addf option.
 func (a *Options) Addf(option string, x ...interface{}) {
 	*a = append(*a, fmt.Sprintf(option, x...))
 }

command/reporter.go

@@ -0,0 +1,119 @@
+package command
+
+import (
+	"strings"
+)
+
+//
+// Verbosity.
+const (
+	// Disabled reports: NOTHING.
+	Disabled = -2
+	// Error reports: error.
+	Error = -1
+	// Default reports: error, started, succeeded.
+	Default = 0
+	// LiveOutput reports: error, started, succeeded, output (live).
+	LiveOutput = 1
+)
+
+//
+// ReportFilter filter reported output.
+type ReportFilter func(in string) (out string)
+
+//
+// Reporter activity reporter.
+type Reporter struct {
+	Filter    ReportFilter
+	Verbosity int
+	index     int
+}
+
+//
+// Run reports command started in task Report.Activity.
+func (r *Reporter) Run(path string, options Options) {
+	switch r.Verbosity {
+	case Disabled:
+	case Error:
+	case Default,
+		LiveOutput:
+		addon.Activity(
+			"[CMD] Running: %s %s",
+			path,
+			strings.Join(options, " "))
+	}
+}
+
+//
+// Succeeded reports command succeeded in task Report.Activity.
+func (r *Reporter) Succeeded(path string) {
+	switch r.Verbosity {
+	case Disabled:
+	case Error:
+	case Default,
+		LiveOutput:
+		addon.Activity("[CMD] %s succeeded.", path)
+	}
+}
+
+//
+// Error reports command failed in task Report.Activity.
+func (r *Reporter) Error(path string, err error, output []byte) {
+	if len(output) == 0 {
+		return
+	}
+	switch r.Verbosity {
+	case Disabled:
+	case Error,
+		Default:
+		addon.Activity(
+			"[CMD] %s failed: %s.\n%s",
+			path,
+			err.Error(),
+			output)
+	case LiveOutput:
+		addon.Activity(
+			"[CMD] %s failed: %s.",
+			path,
+			err.Error())
+	}
+}
+
+//
+// Output reports command output in task Report.Activity.
+// Returns the number of bytes reported.
+func (r *Reporter) Output(buffer []byte, delimited bool) (reported int) {
+	if r.Filter == nil {
+		r.Filter = func(in string) (out string) {
+			out = in
+			return
+		}
+	}
+	switch r.Verbosity {
+	case Disabled:
+	case Error:
+	case Default:
+	case LiveOutput:
+		if r.index >= len(buffer) {
+			return
+		}
+		batch := string(buffer[r.index:])
+		if delimited {
+			end := strings.LastIndex(batch, "\n")
+			if end != -1 {
+				batch = batch[:end]
+				output := r.Filter(batch)
+				addon.Activity("> %s", output)
+				reported = len(output)
+				r.index += len(batch)
+				r.index++
+			}
+		} else {
+			output := r.Filter(batch)
+			addon.Activity("> %s", output)
+			reported = len(batch)
+			r.index = len(buffer)
+		}
+	}
+	return
+}

command/writer.go

@@ -0,0 +1,99 @@
+package command
+
+import (
+	"time"
+)
+
+const (
+	// Backoff rate increment.
+	Backoff = time.Millisecond * 100
+	// MaxBackoff max backoff.
+	MaxBackoff = 10 * Backoff
+	// MinBackoff minimum backoff.
+	MinBackoff = Backoff
+)
+
+//
+// OutputFilter filter output.
+type OutputFilter func(in []byte) (out []byte)
+
+//
+// Writer records command output.
+type Writer struct {
+	Filter   OutputFilter
+	reporter *Reporter
+	buffer   []byte
+	backoff  time.Duration
+	end      chan any
+	ended    chan any
+}
+
+//
+// Write command output.
+func (w *Writer) Write(p []byte) (n int, err error) {
+	if w.Filter == nil {
+		w.Filter = func(in []byte) (out []byte) {
+			out = in
+			return
+		}
+	}
+	n = len(p)
+	p = w.Filter(p)
+	w.buffer = append(w.buffer, p...)
+	if w.ended == nil {
+		w.end = make(chan any)
+		w.ended = make(chan any)
+		go w.report()
+	}
+	return
+}
+
+//
+// End of writing.
+func (w *Writer) End() {
+	if w.end == nil {
+		return
+	}
+	close(w.end)
+	<-w.ended
+	close(w.ended)
+	w.end = nil
+}
+
+//
+// report in task Report.Activity.
+// Rate limited.
+func (w *Writer) report() {
+	w.backoff = MinBackoff
+	ended := false
+	for {
+		select {
+		case <-w.end:
+			ended = true
+		case <-time.After(w.backoff):
+		}
+		n := w.reporter.Output(w.buffer, true)
+		w.adjustBackoff(n)
+		if ended {
+			break
+		}
+	}
+	w.reporter.Output(w.buffer, false)
+	w.ended <- true
+}
+
+//
+// adjustBackoff adjust the backoff as needed.
+// incremented when output reported.
+// decremented when no outstanding output reported.
+func (w *Writer) adjustBackoff(reported int) {
+	if reported > 0 {
+		if w.backoff < MaxBackoff {
+			w.backoff += Backoff
+		}
+	} else {
+		if w.backoff > MinBackoff {
+			w.backoff -= Backoff
+		}
+	}
+}