Set log level using env variable (#1105)

* set log level using env variables

Signed-off-by: Amruta Kale <amrutakale24.1991@gmail.com>

* addressed review comments

Signed-off-by: Amruta Kale <amrutakale24.1991@gmail.com>

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

pkg/log/log.go

@@ -25,6 +25,10 @@ const (
 	InfoLevel Level = Level(logrus.InfoLevel)
 	// ErrorLevel log level.
 	ErrorLevel Level = Level(logrus.ErrorLevel)
+
+	// LevelVarName is the environment variable that controls
+	// init log levels
+	LevelEnvName = "LOG_LEVEL"
 )
 
 // OutputSink describes the current output sink.
@@ -121,6 +125,20 @@ func SetFormatter(format OutputFormat) {
 func init() {
 	SetFormatter(TextFormat)
 	initEnvVarFields()
+	initLogLevel()
+}
+
+func initLogLevel() {
+	level, err := logrus.ParseLevel(os.Getenv(LevelEnvName))
+	if err != nil {
+		level = logrus.InfoLevel
+	}
+	SetLevel(Level(level))
+}
+
+// SetLevel sets the current log level.
+func SetLevel(level Level) {
+	log.SetLevel(logrus.Level(level))
 }
 
 func Info() Logger {

pkg/log/log_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"os"
 	"testing"
 	"time"
 
@@ -105,3 +106,28 @@ func testLogMessage(c *C, msg string, print func(string, ...field.M), fields ...
 	c.Assert(entry["msg"], Equals, msg)
 	return entry
 }
+
+func (s *LogSuite) TestLogLevel(c *C) {
+	log.SetFormatter(&logrus.JSONFormatter{TimestampFormat: time.RFC3339Nano})
+
+	var output bytes.Buffer
+	log.SetOutput(&output)
+	ctx := field.Context(context.Background(), "key", "value")
+	var entry map[string]interface{}
+	//Check if debug level log is printed when log level is info
+	Debug().WithContext(ctx).Print("Testing debug level")
+	err := json.Unmarshal(output.Bytes(), &entry)
+
+	c.Assert(err, NotNil)
+	c.Assert(output.String(), HasLen, 0)
+
+	//Check if debug level log is printed when log level is debug
+	os.Setenv("LOG_LEVEL", "debug")
+	defer os.Unsetenv("LOG_LEVEL")
+	initLogLevel()
+	Debug().WithContext(ctx).Print("Testing debug level")
+	cerr := json.Unmarshal(output.Bytes(), &entry)
+	c.Assert(cerr, IsNil)
+	c.Assert(entry, NotNil)
+	c.Assert(entry["msg"], Equals, "Testing debug level")
+}