fix: Write agent logs to "/tmp/coder-agent.log" for debugging

kylecarbs · kylecarbs · commit a4be45f45537 · 2022-04-30T04:41:54.000Z
It was difficult to obtain logs for the agent if it failed to
start for some reason. Now they'll go to a consistent spot!
diff --git a/agent/agent.go b/agent/agent.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"os/exec"
 	"os/user"
+	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
@@ -21,7 +22,6 @@ import (
 	"github.com/armon/circbuf"
 	"github.com/google/uuid"
 
-	gsyslog "github.com/hashicorp/go-syslog"
 	"go.uber.org/atomic"
 
 	"cdr.dev/slog"
@@ -167,15 +167,9 @@ func (*agent) runStartupScript(ctx context.Context, script string) error {
 		return xerrors.Errorf("get user shell: %w", err)
 	}
 
-	var writer io.WriteCloser
-	// Attempt to use the syslog to write startup information.
-	writer, err = gsyslog.NewLogger(gsyslog.LOG_INFO, "USER", "coder-startup-script")
+	writer, err := os.OpenFile(filepath.Join(os.TempDir(), "coder-startup-script.log"), os.O_CREATE|os.O_RDWR, 0600)
 	if err != nil {
-		// If the syslog isn't supported or cannot be created, use a text file in temp.
-		writer, err = os.CreateTemp("", "coder-startup-script.txt")
-		if err != nil {
-			return xerrors.Errorf("open startup script log file: %w", err)
-		}
+		return xerrors.Errorf("open startup script log file: %w", err)
 	}
 	defer func() {
 		_ = writer.Close()
diff --git a/cli/agent.go b/cli/agent.go
@@ -4,6 +4,8 @@ import (
 	"context"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
 	"time"
 
 	"cloud.google.com/go/compute/metadata"
@@ -37,7 +39,15 @@ func workspaceAgent() *cobra.Command {
 			if err != nil {
 				return xerrors.Errorf("parse %q: %w", rawURL, err)
 			}
-			logger := slog.Make(sloghuman.Sink(cmd.OutOrStdout())).Leveled(slog.LevelDebug)
+
+			logPath := filepath.Join(os.TempDir(), "coder-agent.log")
+			logFile, err := os.OpenFile(logPath, os.O_CREATE|os.O_RDWR, 0600)
+			if err != nil {
+				return xerrors.Errorf("open log %q: %w", logPath, err)
+			}
+			defer logFile.Close()
+
+			logger := slog.Make(sloghuman.Sink(cmd.ErrOrStderr()), sloghuman.Sink(logFile)).Leveled(slog.LevelDebug)
 			client := codersdk.New(coderURL)
 
 			// exchangeToken returns a session token.
