Add migration logger (#2698)

- introduce simple logger in migration internal package
- unit tests
- integrate into main function

tools/migration/internal/logger.go

@@ -0,0 +1,47 @@
+package internal
+
+import (
+	"io"
+	"log"
+	"os"
+)
+
+// Logger logs migration events to disk and, if initialized with verbose,
+// stdout too.
+type Logger struct {
+	closer io.WriteCloser
+	logger *log.Logger
+}
+
+// NewLogger creates a new Logger.  All log writes go to f, the logging file.
+// If the verbose flag is true all log writes also go to stdout.
+func NewLogger(wc io.WriteCloser, verbose bool) *Logger {
+	// by default just write to file
+	var w io.Writer
+	w = wc
+	if verbose {
+		w = io.MultiWriter(wc, os.Stdout)
+	}
+	return &Logger{
+		closer: wc,
+		logger: log.New(w, "", 0),
+	}
+}
+
+// Error logs an error to the logging output.
+func (l *Logger) Error(err error) {
+	if err == nil {
+		return
+	}
+	l.logger.Printf("ERROR: %s", err.Error())
+}
+
+// Print logs a string to the logging output.
+func (l *Logger) Print(msg string) {
+	l.logger.Print(msg)
+}
+
+// Close closes the logfile backing the Logger.
+func (l *Logger) Close() error {
+	return l.closer.Close()
+}

tools/migration/internal/logger_test.go

@@ -0,0 +1,75 @@
+package internal_test
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	. "github.com/filecoin-project/go-filecoin/tools/migration/internal"
+)
+
+func TestLoggerWritesToFile(t *testing.T) {
+	f, err := ioutil.TempFile("", "logfile")
+	require.NoError(t, err)
+	defer func() {
+		require.NoError(t, os.Remove(f.Name()))
+	}()
+
+	logger := NewLogger(f, false)
+	logger.Print("testing print 1")
+	errTest := errors.New("testing error 2")
+	logger.Error(errTest)
+
+	// Reopen file so we can read new writes
+	out, err := ioutil.ReadFile(f.Name())
+	require.NoError(t, err)
+	outStr := string(out)
+	assert.Contains(t, outStr, "testing print 1")
+	expectedErrStr := fmt.Sprintf("ERROR: %s", errTest.Error())
+	assert.Contains(t, outStr, expectedErrStr)
+}
+
+func TestLoggerWritesToBothVerbose(t *testing.T) {
+	// Point os.Stdout to a temp file
+	fStdout, err := ioutil.TempFile("", "stdout")
+	require.NoError(t, err)
+	defer func() {
+		require.NoError(t, os.Remove(fStdout.Name()))
+	}()
+	old := os.Stdout
+	os.Stdout = fStdout
+	defer func() { os.Stdout = old }()
+
+	// Create log file
+	fLogFile, err := ioutil.TempFile("", "logfile")
+	require.NoError(t, err)
+	defer func() {
+		require.NoError(t, os.Remove(fLogFile.Name()))
+	}()
+
+	// Log verbosely
+	logger := NewLogger(fLogFile, true)
+	logger.Print("test line")
+	errTest := errors.New("test err")
+	logger.Error(errTest)
+	expectedErrStr := fmt.Sprintf("ERROR: %s", errTest.Error())
+
+	// Check logfile
+	outLogFile, err := ioutil.ReadFile(fLogFile.Name())
+	require.NoError(t, err)
+	outLogFileStr := string(outLogFile)
+	assert.Contains(t, outLogFileStr, "test line")
+	assert.Contains(t, outLogFileStr, expectedErrStr)
+
+	// Check stdout alias file
+	outStdout, err := ioutil.ReadFile(fStdout.Name())
+	require.NoError(t, err)
+	outStdoutStr := string(outStdout)
+	assert.Contains(t, outStdoutStr, "test line")
+	assert.Contains(t, outStdoutStr, expectedErrStr)
+}

tools/migration/internal/runner.go

@@ -28,17 +28,17 @@ type Migration interface {
 
 // MigrationRunner represent a migration command
 type MigrationRunner struct {
-	verbose    bool
+	logger     *Logger
 	command    string
 	oldRepoOpt string
 }
 
 // NewMigrationRunner builds a MirgrationRunner for the given command and repo options
-func NewMigrationRunner(verb bool, command, oldRepoOpt string) *MigrationRunner {
+func NewMigrationRunner(logger *Logger, command, oldRepoOpt string) *MigrationRunner {
 	// TODO: Issue #2585 Implement repo migration version detection and upgrade decisioning
 
 	return &MigrationRunner{
-		verbose:    verb,
+		logger:     logger,
 		command:    command,
 		oldRepoOpt: oldRepoOpt,
 	}
@@ -47,5 +47,6 @@ func NewMigrationRunner(verb bool, command, oldRepoOpt string) *MigrationRunner
 // Run executes the MigrationRunner
 func (m *MigrationRunner) Run() error {
 	// TODO: Issue #2595 Implement first repo migration
-	return nil
+
+	return m.logger.Close()
 }

tools/migration/internal/runner_test.go

@@ -1,9 +1,12 @@
 package internal_test
 
 import (
+	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	tf "github.com/filecoin-project/go-filecoin/testhelpers/testflags"
 	. "github.com/filecoin-project/go-filecoin/tools/migration/internal"
@@ -12,7 +15,12 @@ import (
 // TODO: Issue #2595 Implement first repo migration
 func TestMigrationRunner_Run(t *testing.T) {
 	tf.UnitTest(t)
-
-	runner := NewMigrationRunner(false, "describe", "/home/filecoin-symlink")
+	dummyLogFile, err := ioutil.TempFile("", "logfile")
+	require.NoError(t, err)
+	logger := NewLogger(dummyLogFile, false)
+	defer func() {
+		require.NoError(t, os.Remove(dummyLogFile.Name()))
+	}()
+	runner := NewMigrationRunner(logger, "describe", "/home/filecoin-symlink")
 	assert.NoError(t, runner.Run())
 }

tools/migration/main.go

@@ -6,9 +6,13 @@ import (
 	"os"
 	"strings"
 
+	"github.com/mitchellh/go-homedir"
+
 	"github.com/filecoin-project/go-filecoin/tools/migration/internal"
 )
 
+const defaultLogFilePath = "~/.filecoin-migration-logs"
+
 // USAGE is the usage of the migration tool
 const USAGE = `
 USAGE
@@ -34,6 +38,8 @@ OPTIONS
 		This message
 	-v --verbose
 		Print diagnostic messages to stdout
+        --log-file
+                The path of the file for writing detailed log output
 
 EXAMPLES
 	for a migration from version 1 to 2:
@@ -60,13 +66,18 @@ func main() { // nolint: deadcode
 	case "-h", "--help":
 		showUsageAndExit(0)
 	case "describe", "buildonly", "migrate", "install":
-		oldRepoOpt, found := findOpt("old-repo", os.Args)
+		logFile, err := openLogFile()
+		if err != nil {
+			exitErr(err.Error())
+		}
+		logger := internal.NewLogger(logFile, getVerbose())
 
+		oldRepoOpt, found := findOpt("old-repo", os.Args)
 		if found == false {
 			exitErr(fmt.Sprintf("Error: --old-repo is required\n%s\n", USAGE))
 		}
 
-		runner := internal.NewMigrationRunner(getVerbose(), command, oldRepoOpt)
+		runner := internal.NewMigrationRunner(logger, command, oldRepoOpt)
 		if err := runner.Run(); err != nil {
 			exitErr(err.Error())
 		}
@@ -97,6 +108,22 @@ func getVerbose() bool {
 	return res
 }
 
+func openLogFile() (*os.File, error) {
+	path, err := getLogFilePath()
+	if err != nil {
+		return nil, err
+	}
+	return os.OpenFile(path, os.O_APPEND|os.O_CREATE, 0644)
+}
+
+func getLogFilePath() (string, error) {
+	if logPath, found := findOpt("--log-file", os.Args); found {
+		return logPath, nil
+	}
+
+	return homedir.Expand(defaultLogFilePath)
+}
+
 // findOpt fetches option values.
 // returns:  string: value of option set with "=". If not set, returns ""
 //           bool:  true if option was found, false if not