Add Cloth Config plugin management screen

sdk/output.go

@@ -0,0 +1,115 @@
+package sdk
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
+	"sync"
+	"time"
+)
+
+var captured = struct {
+	sync.Mutex
+	logs []LogEntry
+}{}
+
+var outputCaptureOnce sync.Once
+
+type streamCapture struct {
+	writer *os.File
+	marker string
+	ack    chan struct{}
+	mu     sync.Mutex
+}
+
+var outputStreams []*streamCapture
+
+func enableOutputCapture() {
+	outputCaptureOnce.Do(func() {
+		outputStreams = append(outputStreams, captureStream("stdout", &os.Stdout))
+		outputStreams = append(outputStreams, captureStream("stderr", &os.Stderr))
+		log.SetOutput(os.Stderr)
+	})
+}
+
+func captureStream(name string, destination **os.File) *streamCapture {
+	reader, writer, err := os.Pipe()
+	if err != nil {
+		return nil
+	}
+
+	stream := &streamCapture{
+		writer: writer,
+		marker: fmt.Sprintf("\x00gmb-flush-%s-%d\x00", name, time.Now().UnixNano()),
+		ack:    make(chan struct{}),
+	}
+	*destination = writer
+	go func() {
+		buffered := bufio.NewReader(reader)
+		for {
+			line, readErr := buffered.ReadString('\n')
+			line = strings.TrimSuffix(strings.TrimSuffix(line, "\n"), "\r")
+			if markerIndex := strings.Index(line, stream.marker); markerIndex >= 0 {
+				captureLine(name, line[:markerIndex])
+				captureLine(name, line[markerIndex+len(stream.marker):])
+				stream.ack <- struct{}{}
+			} else {
+				captureLine(name, line)
+			}
+			if readErr != nil {
+				if readErr != io.EOF {
+					captureLine("stderr", "stdout capture failed: "+readErr.Error())
+				}
+				return
+			}
+		}
+	}()
+	return stream
+}
+
+func captureLine(stream, message string) {
+	if message == "" {
+		return
+	}
+	captured.Lock()
+	captured.logs = append(captured.logs, LogEntry{
+		Stream:             stream,
+		Level:              streamLevel(stream),
+		Message:            message,
+		TimestampUnixMilli: time.Now().UnixMilli(),
+	})
+	captured.Unlock()
+}
+
+func drainCapturedLogs() []LogEntry {
+	for _, stream := range outputStreams {
+		if stream != nil {
+			stream.flush()
+		}
+	}
+
+	captured.Lock()
+	defer captured.Unlock()
+	logs := append([]LogEntry(nil), captured.logs...)
+	captured.logs = captured.logs[:0]
+	return logs
+}
+
+func (stream *streamCapture) flush() {
+	stream.mu.Lock()
+	defer stream.mu.Unlock()
+	if _, err := stream.writer.WriteString(stream.marker + "\n"); err != nil {
+		return
+	}
+	<-stream.ack
+}
+
+func streamLevel(stream string) string {
+	if stream == "stderr" {
+		return "error"
+	}
+	return "info"
+}