internal/pkg: write per-artifact logs

This is currently only used by execArtifact. A later patch will add additional logging facilities.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/exec.go

@@ -418,6 +418,20 @@ func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
 		z.Hostname = "cure-net"
 	}
 	z.Uid, z.Gid = (1<<10)-1, (1<<10)-1
+
+	var status io.Writer
+	if status, err = f.GetStatusWriter(); err != nil {
+		return
+	}
+	bw := f.cache.getWriter(status)
+	defer func() {
+		flushErr := bw.Flush()
+		if err == nil {
+			err = flushErr
+		}
+		f.cache.putWriter(bw)
+	}()
+
 	if msg := f.GetMessage(); msg.IsVerbose() {
 		var stdout, stderr io.ReadCloser
 		if stdout, err = z.StdoutPipe(); err != nil {
@@ -435,9 +449,19 @@ func (a *execArtifact) cure(f *FContext, hostNet bool) (err error) {
 		}()
 
 		stdoutDone, stderrDone := make(chan struct{}), make(chan struct{})
-		go scanVerbose(msg, cancel, stdoutDone, "("+a.name+":1)", stdout)
-		go scanVerbose(msg, cancel, stderrDone, "("+a.name+":2)", stderr)
+		go scanVerbose(
+			msg, cancel, stdoutDone,
+			"("+a.name+":1)",
+			io.TeeReader(stdout, bw),
+		)
+		go scanVerbose(
+			msg, cancel, stderrDone,
+			"("+a.name+":2)",
+			io.TeeReader(stderr, bw),
+		)
 		defer func() { <-stdoutDone; <-stderrDone }()
+	} else {
+		z.Stdout, z.Stderr = status, status
 	}
 
 	z.Dir, z.Env, z.Path, z.Args = a.dir, a.env, a.path, a.args