cli: log daemon output to file

This stores the daemon output in os.UserCacheDir()+"/encore/daemon.log"
for easier post-hoc debugging of a daemon crash.

DEVELOPING.md

@@ -15,7 +15,7 @@ The environment variables are:
 `ENCORE_RUNTIME_PATH` can be set to location of the `compiler/runtime` package in this repository,
 while `ENCORE_GOROOT` must be pointed to where `encore-go` was built.
 
-For more information on this see [cli/internal/env/env.go](cli/internal/env/env.go).
+For more information on this see [cli/daemon/internal/env/env.go](cli/daemon/internal/env/env.go).
 
 ## Architecture
 

cli/cmd/encore/daemon/daemon.go

@@ -35,6 +35,9 @@ import (
 
 // Main runs the daemon.
 func Main() {
+	if err := redirectLogOutput(); err != nil {
+		log.Error().Err(err).Msg("could not setup daemon log file, skipping")
+	}
 	if err := runMain(); err != nil {
 		log.Fatal().Err(err).Msg("daemon failed")
 	}
@@ -299,3 +302,22 @@ func wrap(ctx context.Context) context.Context {
 		"goarch", stdruntime.GOARCH,
 	)
 }
+
+// redirectLogOutput redirects the global logger to also write to a file.
+func redirectLogOutput() error {
+	cache, err := os.UserCacheDir()
+	if err != nil {
+		return err
+	}
+	logPath := filepath.Join(cache, "encore", "daemon.log")
+	if err := os.MkdirAll(filepath.Dir(logPath), 0755); err != nil {
+		return err
+	}
+	f, err := os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
+	if err != nil {
+		return err
+	}
+	log.Info().Msgf("writing output to %s", logPath)
+	log.Logger = log.Output(io.MultiWriter(zerolog.ConsoleWriter{Out: os.Stderr}, f))
+	return nil
+}

cli/daemon/dash/trace.go

@@ -10,9 +10,9 @@ import (
 	"strings"
 	"time"
 
+	"encr.dev/cli/daemon/internal/env"
 	"encr.dev/cli/daemon/runtime/trace"
 	"encr.dev/cli/internal/dedent"
-	"encr.dev/cli/internal/env"
 	tracepb "encr.dev/proto/encore/engine/trace"
 	"github.com/alecthomas/chroma/formatters/html"
 	"github.com/alecthomas/chroma/lexers"

cli/internal/env/env.go → cli/daemon/internal/env/env.go

@@ -2,9 +2,10 @@
 package env
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
+
+	"github.com/rs/zerolog/log"
 )
 
 // EncoreRuntimePath reports the path to the Encore runtime.
@@ -15,9 +16,8 @@ func EncoreRuntimePath() string {
 	}
 	root, ok := determineRoot()
 	if !ok {
-		fmt.Fprintln(os.Stderr, "fatal: could not determine Encore install root.\n"+
+		log.Fatal().Msg("could not determine Encore install root. " +
 			"You can specify the path to the Encore runtime manually by setting the ENCORE_RUNTIME_PATH environment variable.")
-		os.Exit(1)
 	}
 	return filepath.Join(root, "runtime")
 }
@@ -30,9 +30,8 @@ func EncoreGoRoot() string {
 	}
 	root, ok := determineRoot()
 	if !ok {
-		fmt.Fprintln(os.Stderr, "fatal: could not determine Encore install root.\n"+
+		log.Fatal().Msg("could not determine Encore install root. " +
 			"You can specify the path to the Encore GOROOT manually by setting the ENCORE_GOROOT environment variable.")
-		os.Exit(1)
 	}
 	return filepath.Join(root, "encore-go")
 }

cli/daemon/run/run.go

@@ -24,8 +24,8 @@ import (
 	"golang.org/x/mod/modfile"
 
 	"encr.dev/cli/daemon/internal/appfile"
+	"encr.dev/cli/daemon/internal/env"
 	"encr.dev/cli/daemon/internal/sym"
-	"encr.dev/cli/internal/env"
 	"encr.dev/cli/internal/xos"
 	"encr.dev/compiler"
 	"encr.dev/parser"

cli/daemon/run/run_test.go

@@ -9,7 +9,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"encr.dev/cli/internal/env"
+	"encr.dev/cli/daemon/internal/env"
 	"encr.dev/compiler"
 	qt "github.com/frankban/quicktest"
 	"go.uber.org/goleak"

cli/daemon/run/tests.go

@@ -7,7 +7,7 @@ import (
 	"strconv"
 
 	"encr.dev/cli/daemon/internal/appfile"
-	"encr.dev/cli/internal/env"
+	"encr.dev/cli/daemon/internal/env"
 	"encr.dev/compiler"
 	"encr.dev/parser"
 )