Take control over Kopia log level (#2842)

* When building Kopia command line take LogLevel and FileLogLevel from env variables if not specified in parameters

* Add unit test for common Kopia command line builder

* Reuse functionality of getting default value for env variable

* Do not use Kopia in user facing env names.

* Fix comment

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/kopia/command/common.go

@@ -15,16 +15,48 @@
 package command
 
 import (
+	"os"
+
 	"github.com/kanisterio/kanister/pkg/field"
 	"github.com/kanisterio/kanister/pkg/log"
 	"github.com/kanisterio/kanister/pkg/logsafe"
 )
 
+const (
+	// LogLevelVarName is the environment variable that controls datastore log level.
+	LogLevelVarName = "DATA_STORE_LOG_LEVEL"
+	// FileLogLevelVarName is the environment variable that controls datastore file log level.
+	FileLogLevelVarName = "DATA_STORE_FILE_LOG_LEVEL"
+)
+
+func NonEmptyOrDefault[T comparable](t T, def T) T {
+	var empty T
+	if t != empty {
+		return t
+	}
+	return def
+}
+
+func GetEnvOrDefault(name, def string) string {
+	return NonEmptyOrDefault(os.Getenv(name), def)
+}
+
+// LogLevel will return either value from env or "error" as default value
+func LogLevel() string {
+	return GetEnvOrDefault(LogLevelVarName, LogLevelError)
+}
+
+// FileLogLevel will return value from env
+func FileLogLevel() string {
+	return os.Getenv(FileLogLevelVarName)
+}
+
 type CommandArgs struct {
 	RepoPassword   string
 	ConfigFilePath string
 	LogDirectory   string
 	LogLevel       string
+	FileLogLevel   string
 }
 
 func bashCommand(args logsafe.Cmd) []string {
@@ -40,10 +72,12 @@ func stringSliceCommand(args logsafe.Cmd) []string {
 func commonArgs(cmdArgs *CommandArgs) logsafe.Cmd {
 	c := logsafe.NewLoggable(kopiaCommand)
 
-	if cmdArgs.LogLevel != "" {
-		c = c.AppendLoggableKV(logLevelFlag, cmdArgs.LogLevel)
-	} else {
-		c = c.AppendLoggableKV(logLevelFlag, LogLevelError)
+	logLevel := NonEmptyOrDefault(cmdArgs.LogLevel, LogLevel())
+	c = c.AppendLoggableKV(logLevelFlag, logLevel)
+
+	fileLogLevel := NonEmptyOrDefault(cmdArgs.FileLogLevel, FileLogLevel())
+	if fileLogLevel != "" {
+		c = c.AppendLoggableKV(fileLogLevelFlag, fileLogLevel)
 	}
 
 	if cmdArgs.ConfigFilePath != "" {

pkg/kopia/command/common_test.go

@@ -0,0 +1,134 @@
+// Copyright 2024 The Kanister Authors.
+//
+// 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 command
+
+import (
+	"os"
+
+	"gopkg.in/check.v1"
+)
+
+type CommonUtilsSuite struct{}
+
+var _ = check.Suite(&CommonUtilsSuite{})
+
+func (s *CommonUtilsSuite) TestCommonArgs(c *check.C) {
+	for _, tc := range []struct {
+		setup       func() func()
+		arg         *CommandArgs
+		expectedCmd []string
+		comment     string
+	}{
+		{
+			setup:   func() func() { return func() {} },
+			comment: "Default log settings",
+			arg: &CommandArgs{
+				RepoPassword:   "pass123",
+				ConfigFilePath: "/tmp/config.file",
+				LogDirectory:   "/tmp/log.dir",
+			},
+			expectedCmd: []string{"kopia",
+				"--log-level=error",
+				"--config-file=/tmp/config.file",
+				"--log-dir=/tmp/log.dir",
+				"--password=pass123",
+			},
+		}, {
+			setup:   func() func() { return func() {} },
+			comment: "Custom log level passed via args, default file log level",
+			arg: &CommandArgs{
+				LogLevel:       "info",
+				RepoPassword:   "pass123",
+				ConfigFilePath: "/tmp/config.file",
+				LogDirectory:   "/tmp/log.dir",
+			},
+			expectedCmd: []string{"kopia",
+				"--log-level=info",
+				"--config-file=/tmp/config.file",
+				"--log-dir=/tmp/log.dir",
+				"--password=pass123",
+			},
+		}, {
+			setup:   func() func() { return func() {} },
+			comment: "Custom log level and file log level, both passed via args",
+			arg: &CommandArgs{
+				LogLevel:       "info",
+				FileLogLevel:   "info",
+				RepoPassword:   "pass123",
+				ConfigFilePath: "/tmp/config.file",
+				LogDirectory:   "/tmp/log.dir",
+			},
+			expectedCmd: []string{"kopia",
+				"--log-level=info",
+				"--file-log-level=info",
+				"--config-file=/tmp/config.file",
+				"--log-dir=/tmp/log.dir",
+				"--password=pass123",
+			},
+		}, {
+			setup: func() func() {
+				origLogLevel := os.Getenv(LogLevelVarName)
+				os.Setenv(LogLevelVarName, "debug")
+				return func() {
+					os.Setenv(LogLevelVarName, origLogLevel)
+				}
+			},
+			comment: "Custom log level passed via env variable, file log level passed via args",
+			arg: &CommandArgs{
+				FileLogLevel:   "info",
+				RepoPassword:   "pass123",
+				ConfigFilePath: "/tmp/config.file",
+				LogDirectory:   "/tmp/log.dir",
+			},
+			expectedCmd: []string{"kopia",
+				"--log-level=debug",
+				"--file-log-level=info",
+				"--config-file=/tmp/config.file",
+				"--log-dir=/tmp/log.dir",
+				"--password=pass123",
+			},
+		}, {
+			setup: func() func() {
+				origLogLevel := os.Getenv(LogLevelVarName)
+				origFileLogLevel := os.Getenv(FileLogLevelVarName)
+				os.Setenv(LogLevelVarName, "debug")
+				os.Setenv(FileLogLevelVarName, "debug")
+				return func() {
+					os.Setenv(LogLevelVarName, origLogLevel)
+					os.Setenv(FileLogLevelVarName, origFileLogLevel)
+				}
+			},
+			comment: "Custom log level and file log level both passed via env variable",
+			arg: &CommandArgs{
+				RepoPassword:   "pass123",
+				ConfigFilePath: "/tmp/config.file",
+				LogDirectory:   "/tmp/log.dir",
+			},
+			expectedCmd: []string{"kopia",
+				"--log-level=debug",
+				"--file-log-level=debug",
+				"--config-file=/tmp/config.file",
+				"--log-dir=/tmp/log.dir",
+				"--password=pass123",
+			},
+		},
+	} {
+		c.Log(tc.comment)
+		cleanup := tc.setup()
+		defer cleanup()
+		cmd := stringSliceCommand(commonArgs(tc.arg))
+		c.Assert(cmd, check.DeepEquals, tc.expectedCmd)
+	}
+}

pkg/kopia/command/const.go

@@ -41,6 +41,7 @@ const (
 	jsonFlag                   = "--json"
 	logDirectoryFlag           = "--log-dir"
 	logLevelFlag               = "--log-level"
+	fileLogLevelFlag           = "--file-log-level"
 	LogLevelError              = "error"
 	LogLevelInfo               = "info"
 	parallelFlag               = "--parallel"