Improve error message for state.json (#4251)

Closes #4234.
FerretDB · Apr 28, 2024 · a84136f · a84136f
1 parent 89f22e4
commit a84136f
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Showing 4 changed files with 88 additions and 4 deletions.
diff --git a/cmd/ferretdb/main.go b/cmd/ferretdb/main.go
@@ -218,7 +218,6 @@ func defaultLogLevel() zapcore.Level {
 func setupState() *state.Provider {
 	var f string
 
-	// https://github.com/alecthomas/kong/issues/389
 	if cli.StateDir != "" && cli.StateDir != "-" {
 		var err error
 		if f, err = filepath.Abs(filepath.Join(cli.StateDir, "state.json")); err != nil {
@@ -228,7 +227,7 @@ func setupState() *state.Provider {
 
 	sp, err := state.NewProvider(f)
 	if err != nil {
-		log.Fatalf("Failed to create state provider: %s.", err)
+		log.Fatal(stateFileProblem(f, err))
 	}
 
 	return sp
@@ -369,7 +368,6 @@ func run() {
 		logger.Sugar().Fatal("--test-disable-pushdown and --test-enable-nested-pushdown should not be set at the same time")
 	}
 
-	// https://github.com/alecthomas/kong/issues/389
 	if cli.DebugAddr != "" && cli.DebugAddr != "-" {
 		wg.Add(1)
 

diff --git a/cmd/ferretdb/main_unix.go b/cmd/ferretdb/main_unix.go
@@ -0,0 +1,63 @@
+// Copyright 2021 FerretDB Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build unix
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/user"
+	"strconv"
+	"syscall"
+)
+
+// stateFileProblem adds details to the state file access error.
+func stateFileProblem(f string, err error) string {
+	res := fmt.Sprintf("Failed to create state provider: %s.\n", err)
+
+	if u, _ := user.Current(); u != nil {
+		var group string
+		if g, _ := user.LookupGroupId(u.Gid); g != nil {
+			group = g.Name
+		}
+
+		res += fmt.Sprintf("FerretDB is running as %s:%s (%s:%s). ", u.Username, group, u.Uid, u.Gid)
+	}
+
+	if fi, _ := os.Stat(f); fi != nil {
+		var username, group string
+		var uid, gid uint64
+
+		if s, _ := fi.Sys().(*syscall.Stat_t); s != nil {
+			uid = uint64(s.Uid)
+			if u, _ := user.LookupId(strconv.FormatUint(uid, 10)); u != nil {
+				username = u.Username
+			}
+
+			gid = uint64(s.Gid)
+			if g, _ := user.LookupGroupId(strconv.FormatUint(gid, 10)); g != nil {
+				group = g.Name
+			}
+		}
+
+		res += fmt.Sprintf("%s permissions are %s.", f, fi.Mode().String())
+		if username != "" {
+			res += fmt.Sprintf(" Owned by %s:%s (%d:%d).", username, group, uid, gid)
+		}
+	}
+
+	return res
+}
diff --git a/cmd/ferretdb/main_windows.go b/cmd/ferretdb/main_windows.go
@@ -0,0 +1,22 @@
+// Copyright 2021 FerretDB Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import "fmt"
+
+// stateFileProblem returns the state file access error.
+func stateFileProblem(_ string, err error) string {
+	return fmt.Sprintf("Failed to create state provider: %s.", err)
+}
diff --git a/internal/util/state/provider.go b/internal/util/state/provider.go
@@ -53,7 +53,8 @@ func NewProvider(filename string) (*Provider, error) {
 	p.s.fill()
 
 	// Simply overwrite state to handle all errors and edge cases
-	// like missing directory, corrupted file, invalid UUID, etc.
+	// like missing directory, corrupted file, invalid UUID, etc.,
+	// and also to check permissions.
 	if err := persistState(p.s, p.filename); err != nil {
 		return p, fmt.Errorf("failed to persist state: %w", err)
 	}