move implementation to internal/ directory (#828)

internal/client/pprof_activity_trace.go

@@ -0,0 +1,44 @@
+package client
+
+import (
+	"context"
+	"io"
+	"log"
+	"os"
+
+	"golang.org/x/net/websocket"
+
+	"github.com/zrepl/zrepl/internal/cli"
+)
+
+var pprofActivityTraceCmd = &cli.Subcommand{
+	Use:   "activity-trace ZREPL_PPROF_HOST:ZREPL_PPROF_PORT",
+	Short: "attach to zrepl daemon with activated pprof listener and dump an activity-trace to stdout",
+	Run:   runPProfActivityTrace,
+}
+
+func runPProfActivityTrace(ctx context.Context, subcommand *cli.Subcommand, args []string) error {
+	log := log.New(os.Stderr, "", 0)
+
+	die := func() {
+		log.Printf("exiting after error")
+		os.Exit(1)
+	}
+
+	if len(args) != 1 {
+		log.Printf("exactly one positional argument is required")
+		die()
+	}
+
+	url := "ws://" + args[0] + "/debug/zrepl/activity-trace" // FIXME dont' repeat that
+
+	log.Printf("attaching to activity trace stream %s", url)
+	ws, err := websocket.Dial(url, "", url)
+	if err != nil {
+		log.Printf("error: %s", err)
+		die()
+	}
+
+	_, err = io.Copy(os.Stdout, ws)
+	return err
+}