Add an option to format logs with JSON (#378)

* add an option to format logs with JSON

* added integration tests for log format

* clean up format options

cli/cli.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"strings"
 
 	"github.com/arduino/arduino-cli/cli/board"
 	"github.com/arduino/arduino-cli/cli/compile"
@@ -51,8 +52,9 @@ var (
 		PersistentPreRun: preRun,
 	}
 
-	verbose bool
-	logFile string
+	verbose   bool
+	logFile   string
+	logFormat string
 )
 
 const (
@@ -80,6 +82,7 @@ func createCliCommandTree(cmd *cobra.Command) {
 	cmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "Print the logs on the standard output.")
 	cmd.PersistentFlags().StringVar(&globals.LogLevel, "log-level", defaultLogLevel, "Messages with this level and above will be logged (default: warn).")
 	cmd.PersistentFlags().StringVar(&logFile, "log-file", "", "Path to the file where logs will be written.")
+	cmd.PersistentFlags().StringVar(&logFormat, "log-format", "text", "The output format for the logs, can be [text|json].")
 	cmd.PersistentFlags().StringVar(&globals.OutputFormat, "format", "text", "The output format, can be [text|json].")
 	cmd.PersistentFlags().StringVar(&globals.YAMLConfigFile, "config-file", "", "The custom config file (if not specified the default will be used).")
 	cmd.PersistentFlags().StringSliceVar(&globals.AdditionalUrls, "additional-urls", []string{}, "Additional URLs for the board manager.")
@@ -111,6 +114,10 @@ func parseFormatString(arg string) (feedback.OutputFormat, bool) {
 }
 
 func preRun(cmd *cobra.Command, args []string) {
+	// normalize the format strings
+	globals.OutputFormat = strings.ToLower(globals.OutputFormat)
+	logFormat = strings.ToLower(logFormat)
+
 	// should we log to file?
 	if logFile != "" {
 		file, err := os.OpenFile(logFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
@@ -120,7 +127,11 @@ func preRun(cmd *cobra.Command, args []string) {
 		}
 
 		// we use a hook so we don't get color codes in the log file
-		logrus.AddHook(lfshook.NewHook(file, &logrus.TextFormatter{}))
+		if logFormat == "json" {
+			logrus.AddHook(lfshook.NewHook(file, &logrus.JSONFormatter{}))
+		} else {
+			logrus.AddHook(lfshook.NewHook(file, &logrus.TextFormatter{}))
+		}
 	}
 
 	// should we log to stdout?
@@ -142,15 +153,21 @@ func preRun(cmd *cobra.Command, args []string) {
 		logrus.SetLevel(lvl)
 	}
 
-	// check the right format was passed
-	if f, found := parseFormatString(globals.OutputFormat); !found {
+	// set the Logger format
+	if logFormat == "json" {
+		logrus.SetFormatter(&logrus.JSONFormatter{})
+	}
+
+	// check the right output format was passed
+	format, found := parseFormatString(globals.OutputFormat)
+	if !found {
 		feedback.Error("Invalid output format: " + globals.OutputFormat)
 		os.Exit(errorcodes.ErrBadCall)
-	} else {
-		// use the format to configure the Feedback
-		feedback.SetFormat(f)
 	}
 
+	// use the output format to configure the Feedback
+	feedback.SetFormat(format)
+
 	globals.InitConfigs()
 
 	logrus.Info(globals.VersionInfo.Application + "-" + globals.VersionInfo.VersionString)

test/test_main.py

@@ -12,7 +12,9 @@
 # otherwise use the software for commercial activities involving the Arduino
 # software without disclosing the source code of your own applications. To purchase
 # a commercial license, send an email to license@arduino.cc.
+import os
 import json
+
 import semver
 
 
@@ -36,3 +38,37 @@ def test_version(run_command):
     assert parsed_out.get("Application", False) == "arduino-cli"
     assert isinstance(semver.parse(parsed_out.get("VersionString", False)), dict)
     assert isinstance(parsed_out.get("Commit", False), str)
+
+
+def test_log_options(run_command, data_dir):
+    """
+    using `version` as a test command
+    """
+
+    # no logs
+    out_lines = run_command("version").stdout.strip().split("\n")
+    assert len(out_lines) == 1
+
+    # plain text logs on stdoud
+    out_lines = run_command("version -v").stdout.strip().split("\n")
+    assert len(out_lines) > 1
+    assert out_lines[0].startswith("\x1b[36mINFO\x1b[0m")  # account for the colors
+
+    # plain text logs on file
+    log_file = os.path.join(data_dir, "log.txt")
+    run_command("version --log-file " + log_file)
+    with open(log_file) as f:
+        lines = f.readlines()
+        assert lines[0].startswith('time="')  # file format is different from console
+
+    # json on stdout
+    out_lines = run_command("version -v --log-format JSON").stdout.strip().split("\n")
+    lg = json.loads(out_lines[0])
+    assert "level" in lg
+
+    # json on file
+    log_file = os.path.join(data_dir, "log.json")
+    run_command("version --log-format json --log-file " + log_file)
+    with open(log_file) as f:
+        for line in f.readlines():
+            json.loads(line)