all logs now have an op field

build/lint/Dockerfile

@@ -22,7 +22,7 @@ RUN curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.s
 # | Last instructions of this build.
 # |
 
-# Define our workding outside of $GOPATH (we're using go modules).
+# Define our working directory outside of $GOPATH (we're using go modules).
 WORKDIR /lint
 
 # Copy our module dependencies definitions.

build/tests/Dockerfile

@@ -35,7 +35,7 @@ ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
 # | Last instructions of this build.
 # |
 
-# Define our workding outside of $GOPATH (we're using go modules).
+# Define our working directory outside of $GOPATH (we're using go modules).
 WORKDIR /tests
 
 # Copy our module dependencies definitions.

cmd/gotenberg/main.go

@@ -9,8 +9,8 @@ import (
 	"time"
 
 	"github.com/thecodingmachine/gotenberg/internal/app/api"
-	conf "github.com/thecodingmachine/gotenberg/internal/pkg/config"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/config"
-	log "github.com/thecodingmachine/gotenberg/internal/pkg/logger"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/logger"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/pm2"
 )
 
@@ -19,12 +19,13 @@ import (
 var version = "snapshot"
 
 func main() {
-	config, err := conf.FromEnv()
+	const op = "main"
-	systemLogger := log.New(config.LogLevel(), "system")
+	config, err := config.FromEnv()
+	systemLogger := logger.New(config.LogLevel(), "system")
 	if err != nil {
-		systemLogger.Fatal(err)
+		systemLogger.FatalOp(op, err)
 	}
-	systemLogger.Infof("Gotenberg %s", version)
+	systemLogger.InfofOp(op, "Gotenberg %s", version)
 	// start PM2 processes.
 	var processes []pm2.Process
 	if config.EnableChromeEndpoints() {
@@ -34,19 +35,19 @@ func main() {
 		processes = append(processes, pm2.NewUnoconv(systemLogger))
 	}
 	for _, p := range processes {
-		systemLogger.Infof("starting %s with PM2...", p.Fullname())
+		systemLogger.InfofOp(op, "starting %s with PM2...", p.Fullname())
 		if err := p.Start(); err != nil {
-			systemLogger.Fatal(err)
+			systemLogger.FatalOp(op, err)
 		}
 	}
 	// run our API in a goroutine so that it doesn't block.
 	// create our API.
 	srv := api.New(config)
 	go func() {
-		systemLogger.Infof("http server started on port %s", config.DefaultListenPort())
+		systemLogger.InfofOp(op, "http server started on port %s", config.DefaultListenPort())
 		if err := srv.Start(fmt.Sprintf(":%s", config.DefaultListenPort())); err != nil {
 			if err != http.ErrServerClosed {
-				systemLogger.Fatal(err)
+				systemLogger.FatalOp(op, err)
 			}
 		}
 	}()
@@ -61,17 +62,17 @@ func main() {
 	defer cancel()
 	// doesn't block if no connections, but will otherwise wait
 	// until the timeout deadline.
-	systemLogger.Info("shutting down http server...")
+	systemLogger.InfofOp(op, "shutting down http server...")
 	if err := srv.Shutdown(ctx); err != nil {
-		systemLogger.Fatal(err)
+		systemLogger.FatalOp(op, err)
 	}
 	// shutdown PM2 processes.
 	for _, p := range processes {
-		systemLogger.Infof("shutting down %s with PM2...", p.Fullname())
+		systemLogger.InfofOp(op, "shutting down %s with PM2...", p.Fullname())
 		if err := p.Shutdown(); err != nil {
-			systemLogger.Fatal(err)
+			systemLogger.FatalOp(op, err)
 		}
 	}
-	systemLogger.Info("bye!")
+	systemLogger.InfofOp(op, "bye!")
 	os.Exit(0)
 }

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/labstack/echo/v4 v4.1.6
 	github.com/labstack/gommon v0.2.9
 	github.com/mafredri/cdp v0.23.4
+	github.com/mattn/go-isatty v0.0.8
 	github.com/microcosm-cc/bluemonday v1.0.2
 	github.com/russross/blackfriday/v2 v2.0.1
 	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect

internal/app/api/pkg/context/context.go

@@ -74,11 +74,11 @@ func (ctx *Context) WithResource(resourceDirPath string) error {
 // LogRequestResult logs the result of a request.
 // This method should only be used by a middleware!
 func (ctx *Context) LogRequestResult(err error, isDebug bool) error {
+	const op = "context.LogRequestResult"
 	req := ctx.Request()
 	resp := ctx.Response()
 	stopTime := time.Now()
 	fields := map[string]interface{}{
-		"time_rfc3339":  timeRFC3339(), // FIXME required?
 		"remote_ip":     ctx.RealIP(),
 		"host":          req.Host,
 		"uri":           req.RequestURI,
@@ -93,21 +93,17 @@ func (ctx *Context) LogRequestResult(err error, isDebug bool) error {
 		"bytes_out":     bytesOut(resp),
 	}
 	if err != nil {
-		ctx.logger.WithFields(fields).Error("request failed")
+		ctx.logger.WithFields(fields).ErrorfOp(op, "request failed")
 		return err
 	}
 	if isDebug {
-		ctx.logger.WithFields(fields).Debug("request handled")
+		ctx.logger.WithFields(fields).DebugfOp(op, "request handled")
 		return nil
 	}
-	ctx.logger.WithFields(fields).Info("request handled")
+	ctx.logger.WithFields(fields).InfofOp(op, "request handled")
 	return nil
 }
 
-func timeRFC3339() string {
-	return time.Now().Format(time.RFC3339)
-}
-
 func path(r *http.Request) string {
 	path := r.URL.Path
 	if path == "" {

internal/app/api/pkg/middleware/error.go

@@ -20,8 +20,9 @@ func Error() echo.MiddlewareFunc {
 			}
 			// we log the initial error before returning
 			// the HTTP error.
+			errOp := standarderror.Op(err)
 			logger := ctx.StandardLogger()
-			logger.Error(err.Error())
+			logger.ErrorOp(errOp, err)
 			// handle our custom HTTP error.
 			var httpErr error
 			errCode := standarderror.Code(err)

internal/app/api/pkg/resource/resource.go

@@ -318,7 +318,7 @@ func (r *Resource) float64(formField string, defaultValue float64) (float64, err
 	if err != nil {
 		return 0.0, &standarderror.Error{
 			Code:    standarderror.Invalid,
-			Message: fmt.Sprintf("'%s' is not a float", formField),
+			Message: fmt.Sprintf("'%s' is not a float, got '%s'", formField, v),
 			Op:      op,
 		}
 	}
@@ -338,7 +338,7 @@ func (r *Resource) bool(formField string, defaultValue bool) (bool, error) {
 	if err != nil {
 		return false, &standarderror.Error{
 			Code:    standarderror.Invalid,
-			Message: fmt.Sprintf("'%s' is not a boolean", formField),
+			Message: fmt.Sprintf("'%s' is not a boolean, got '%s'", formField, v),
 			Op:      op,
 		}
 	}

internal/pkg/config/config.go

@@ -5,7 +5,8 @@ import (
 	"os"
 	"strconv"
 
-	log "github.com/sirupsen/logrus"
+	"github.com/sirupsen/logrus"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 const (
@@ -16,12 +17,14 @@ const (
 	logLevelEnvVar            = "LOG_LEVEL"
 )
 
+// Config contains the application
+// configuration.
 type Config struct {
 	defaultWaitTimeout     float64
 	defaultListenPort      string
 	enableChromeEndpoints  bool
 	enableUnoconvEndpoints bool
-	logLevel               log.Level
+	logLevel               logrus.Level
 }
 
 func defaultConfig() *Config {
@@ -30,51 +33,85 @@ func defaultConfig() *Config {
 		defaultListenPort:      "3000",
 		enableChromeEndpoints:  true,
 		enableUnoconvEndpoints: true,
-		logLevel:               log.InfoLevel,
+		logLevel:               logrus.InfoLevel,
 	}
 }
 
+// FromEnv fetches configuration
+// from environment variables.
 func FromEnv() (*Config, error) {
+	const op = "config.FromEnv"
 	c := defaultConfig()
 	defaultWaitTimeout, err := defaultWaitTimeoutFromEnv(defaultWaitTimeoutEnvVar, c.DefaultWaitTimeout())
 	c.defaultWaitTimeout = defaultWaitTimeout
 	if err != nil {
-		return c, err
+		return c, &standarderror.Error{Op: op, Err: err}
 	}
 	defaultListenPort, err := defaultListenPortFromEnv(defaultListenPortEnvVar, c.DefaultListenPort())
 	c.defaultListenPort = defaultListenPort
 	if err != nil {
-		return c, err
+		return c, &standarderror.Error{Op: op, Err: err}
 	}
 	disableChromeEndpoints, err := boolFromEnv(disableGoogleChromeEnvVar, c.EnableChromeEndpoints())
 	c.enableChromeEndpoints = !disableChromeEndpoints
 	if err != nil {
-		return c, err
+		return c, &standarderror.Error{Op: op, Err: err}
 	}
 	disableUnoconvEndpoints, err := boolFromEnv(disableUnoconvEnvVar, c.EnableUnoconvEndpoints())
 	c.enableUnoconvEndpoints = !disableUnoconvEndpoints
 	if err != nil {
-		return c, err
+		return c, &standarderror.Error{Op: op, Err: err}
 	}
 	logLevel, err := logLevelFromEnv(logLevelEnvVar, c.LogLevel())
 	c.logLevel = logLevel
 	if err != nil {
-		return c, err
+		return c, &standarderror.Error{Op: op, Err: err}
 	}
 	return c, nil
 }
 
-func (c *Config) DefaultWaitTimeout() float64  { return c.defaultWaitTimeout }
+// DefaultWaitTimeout returns the default
-func (c *Config) DefaultListenPort() string    { return c.defaultListenPort }
+// wait timeout from the configuration.
-func (c *Config) EnableChromeEndpoints() bool  { return c.enableChromeEndpoints }
+func (c *Config) DefaultWaitTimeout() float64 {
-func (c *Config) EnableUnoconvEndpoints() bool { return c.enableUnoconvEndpoints }
+	return c.defaultWaitTimeout
-func (c *Config) LogLevel() log.Level          { return c.logLevel }
+}
+
+// DefaultListenPort returns the default
+// listen port from the configuration.
+func (c *Config) DefaultListenPort() string {
+	return c.defaultListenPort
+}
+
+// EnableChromeEndpoints returns true if
+// Chrome endpoints are enabled in the
+// configuration.
+func (c *Config) EnableChromeEndpoints() bool {
+	return c.enableChromeEndpoints
+}
+
+// EnableUnoconvEndpoints returns true if
+// Unoconv endpoints are enabled in the
+// configuration.
+func (c *Config) EnableUnoconvEndpoints() bool {
+	return c.enableUnoconvEndpoints
+}
+
+// LogLevel returns the logrus.Level from
+// the configuration.
+func (c *Config) LogLevel() logrus.Level {
+	return c.logLevel
+}
 
 func defaultWaitTimeoutFromEnv(envVar string, defaultValue float64) (float64, error) {
+	const op = "defaultWaitTimeoutFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		waitTimeout, err := strconv.ParseFloat(v, 64)
 		if err != nil {
-			return defaultValue, fmt.Errorf("%s: wrong value: want float got %v", envVar, err)
+			return defaultValue, &standarderror.Error{
+				Code:    standarderror.Invalid,
+				Message: fmt.Sprintf("'%s' is not a float, got '%s'", envVar, v),
+				Op:      op,
+			}
 		}
 		return waitTimeout, nil
 	}
@@ -82,13 +119,22 @@ func defaultWaitTimeoutFromEnv(envVar string, defaultValue float64) (float64, er
 }
 
 func defaultListenPortFromEnv(envVar string, defaultValue string) (string, error) {
+	const op = "defaultListenPortFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		portAsUint, err := strconv.ParseUint(v, 10, 64)
 		if err != nil {
-			return defaultValue, fmt.Errorf("%s: wrong value: want uint got %v", envVar, err)
+			return defaultValue, &standarderror.Error{
+				Code:    standarderror.Invalid,
+				Message: fmt.Sprintf("'%s' is not a uint, got '%s'", envVar, v),
+				Op:      op,
+			}
 		}
 		if portAsUint > 65535 {
-			return defaultValue, fmt.Errorf("%s: wrong value: want uint < 65535 got %d", envVar, portAsUint)
+			return defaultValue, &standarderror.Error{
+				Code:    standarderror.Invalid,
+				Message: fmt.Sprintf("'%s' is not a uint < 65535, got '%d'", envVar, portAsUint),
+				Op:      op,
+			}
 		}
 		return v, nil
 	}
@@ -96,26 +142,36 @@ func defaultListenPortFromEnv(envVar string, defaultValue string) (string, error
 }
 
 func boolFromEnv(envVar string, defaultValue bool) (bool, error) {
+	const op = "boolFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		if v != "1" && v != "0" {
-			return defaultValue, fmt.Errorf("%s: wrong value: want \"0\" or \"1\" got %s", envVar, v)
+			return defaultValue, &standarderror.Error{
+				Code:    standarderror.Invalid,
+				Message: fmt.Sprintf("'%s' is not '0' or '1', got %s", envVar, v),
+				Op:      op,
+			}
 		}
 		return v == "1", nil
 	}
 	return defaultValue, nil
 }
 
-func logLevelFromEnv(envVar string, defaultValue log.Level) (log.Level, error) {
+func logLevelFromEnv(envVar string, defaultValue logrus.Level) (logrus.Level, error) {
+	const op = "logLevelFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		switch v {
 		case "DEBUG":
-			return log.DebugLevel, nil
+			return logrus.DebugLevel, nil
 		case "INFO":
-			return log.InfoLevel, nil
+			return logrus.InfoLevel, nil
 		case "ERROR":
-			return log.ErrorLevel, nil
+			return logrus.ErrorLevel, nil
 		default:
-			return defaultValue, fmt.Errorf("%s: wrong value: want \"DEBUG\",\"INFO\" or \"ERROR\" got %s", envVar, v)
+			return defaultValue, &standarderror.Error{
+				Code:    standarderror.Invalid,
+				Message: fmt.Sprintf("'%s' is not 'DEBUG', 'INFO' or 'ERROR', got '%s'", envVar, v),
+				Op:      op,
+			}
 		}
 	}
 	return defaultValue, nil

internal/pkg/config/doc.go

@@ -1 +1,3 @@
+// Package config gathers all
+// configuration data.
 package config

internal/pkg/logger/doc.go

@@ -1 +1,3 @@
+// Package logger defines a standard
+// logger for the application.
 package logger

internal/pkg/logger/logger.go

@@ -1,33 +1,63 @@
 package logger
 
 import (
+	"os"
+
+	"github.com/mattn/go-isatty"
 	"github.com/sirupsen/logrus"
 )
 
 // Logger enforces specific log message formats.
 type Logger struct {
-	*logrus.Entry
+	entry *logrus.Entry
 }
 
 // New initializes the logger.
 func New(level logrus.Level, trace string) *Logger {
 	l := logrus.New()
 	l.SetLevel(level)
-	// TODO no formatter if TTY.
+	if !isatty.IsTerminal(os.Stdout.Fd()) {
-	l.SetFormatter(&logrus.JSONFormatter{})
+		l.SetFormatter(&logrus.JSONFormatter{})
+	}
 	return &Logger{
-		l.WithField("trace", trace),
+		entry: l.WithField("trace", trace),
+	}
+}
+
+// WithFields creates a new logger with
+// given fields.
+func (l *Logger) WithFields(fields map[string]interface{}) *Logger {
+	return &Logger{
+		entry: l.entry.WithFields(fields),
 	}
 }
 
 // DebugfOp logs a debug message for given
 // logical operation.
 func (l *Logger) DebugfOp(op string, format string, args ...interface{}) {
-	l.WithField("op", op).Debugf(format, args...)
+	l.entry.WithField("op", op).Debugf(format, args...)
 }
 
-// ErrorOp logs an error message for given
+// InfofOp logs an info message for given
+// logical operation.
+func (l *Logger) InfofOp(op string, format string, args ...interface{}) {
+	l.entry.WithField("op", op).Infof(format, args...)
+}
+
+// ErrorOp logs an error for given
 // logical operation.
 func (l *Logger) ErrorOp(op string, err error) {
-	l.WithField("op", op).Error(err.Error())
+	l.entry.WithField("op", op).Error(err.Error())
+}
+
+// ErrorfOp logs an error message for given
+// logical operation.
+func (l *Logger) ErrorfOp(op string, message string) {
+	l.entry.WithField("op", op).Error(message)
+}
+
+// FatalOp logs an error message for given
+// logical operation.
+func (l *Logger) FatalOp(op string, err error) {
+	l.entry.WithField("op", op).Error(err.Error())
 }

internal/pkg/pm2/chrome.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/mafredri/cdp/devtool"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/logger"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 const warmupTime = 10 * time.Second
@@ -27,11 +28,19 @@ func (p *chrome) Fullname() string {
 }
 
 func (p *chrome) Start() error {
-	return p.manager.start(p)
+	const op = "chrome.Start"
+	if err := p.manager.start(p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }
 
 func (p *chrome) Shutdown() error {
-	return p.manager.shutdown(p)
+	const op = "chrome.Shutdown"
+	if err := p.manager.shutdown(p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }
 
 func (p *chrome) args() []string {
@@ -58,24 +67,38 @@ func (p *chrome) name() string {
 }
 
 func (p *chrome) viable() bool {
+	const debugOp = "chrome.viable"
 	// check if Google Chrome is correctly running.
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	p.manager.logger.Debugf(
+	p.manager.logger.DebugfOp(
-		"%s: checking liveness via debug version endpoint http://localhost:9222/json/version",
+		debugOp,
-		p.Fullname(),
+		"checking liveness via debug version endpoint http://localhost:9222/json/version",
 	)
 	v, err := devtool.New("http://localhost:9222").Version(ctx)
 	if err != nil {
-		p.manager.logger.Debugf("%s: debug version endpoint returned error: %v", p.Fullname(), err)
+		p.manager.logger.DebugfOp(
+			debugOp,
+			"debug version endpoint returned error: %v",
+			err,
+		)
 		return false
 	}
-	p.manager.logger.Debugf("%s: debug version endpoint returned version info: %+v", p.Fullname(), *v)
+	p.manager.logger.DebugfOp(
+		debugOp,
+		"debug version endpoint returned version info: %+v",
+		*v,
+	)
 	return true
 }
 
 func (p *chrome) warmup() {
-	p.manager.logger.Debugf("%s: allowing %v to startup", p.Fullname(), warmupTime)
+	const debugOp = "chrome.warmup"
+	p.manager.logger.DebugfOp(
+		debugOp,
+		"allowing %v to startup",
+		warmupTime,
+	)
 	time.Sleep(warmupTime)
 }
 

internal/pkg/pm2/pm2.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/thecodingmachine/gotenberg/internal/pkg/logger"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 const (
@@ -34,8 +35,9 @@ type processManager struct {
 }
 
 func (m *processManager) start(p Process) error {
+	const op = "pm2.start"
 	if err := m.pm2(p, "start"); err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p.warmup()
 	if !p.viable() {
@@ -43,14 +45,17 @@ func (m *processManager) start(p Process) error {
 		for attempts < 5 && !p.viable() {
 			if err := m.pm2(p, "restart"); err != nil {
 				m.heuristicState = errorState
-				return err
+				return &standarderror.Error{Op: op, Err: err}
 			}
 			p.warmup()
 			attempts++
 		}
 		if !p.viable() {
 			m.heuristicState = errorState
-			return fmt.Errorf("failed to launch %s", p.Fullname())
+			return &standarderror.Error{
+				Op:      op,
+				Message: fmt.Sprintf("failed to launch %s", p.Fullname()),
+			}
 		}
 	}
 	m.heuristicState = runningState
@@ -58,18 +63,20 @@ func (m *processManager) start(p Process) error {
 }
 
 func (m *processManager) shutdown(p Process) error {
+	const op = "pm2.shutdown"
 	if m.heuristicState != runningState {
 		return nil
 	}
 	if err := m.pm2(p, "stop"); err != nil {
 		m.heuristicState = errorState
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	m.heuristicState = stoppedState
 	return nil
 }
 
 func (m *processManager) pm2(p Process, cmdName string) error {
+	const op = "pm2.pm2"
 	cmdArgs := []string{
 		cmdName,
 		p.name(),
@@ -82,35 +89,36 @@ func (m *processManager) pm2(p Process, cmdName string) error {
 		"pm2",
 		cmdArgs...,
 	)
-	m.logger.Debugf("executing command: %v", strings.Join(cmd.Args, " "))
+	m.logger.DebugfOp(op, "executing command: %s", strings.Join(cmd.Args, " "))
 	processStdOut, err := cmd.StdoutPipe()
 	if err != nil {
-		return fmt.Errorf("failed getting stdout from %s: %s", p.Fullname(), err)
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	processStdErr, err := cmd.StderrPipe()
 	if err != nil {
-		return fmt.Errorf("failed getting stderr from %s: %s", p.Fullname(), err)
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	readFromPipe := func(outputType string, reader io.ReadCloser) {
+		readFromPipeOp := fmt.Sprintf("pm2.%s.%s", p.name(), outputType)
 		r := bufio.NewReader(reader)
 		defer reader.Close() // nolint: errcheck
 		for {
 			line, _, err := r.ReadLine()
 			if err != nil {
 				if err != io.EOF {
-					m.logger.Errorf("error reading from %s for process %s", outputType, p.Fullname())
+					m.logger.ErrorOp(readFromPipeOp, err)
 				}
 				break
 			}
 			if len(line) != 0 {
-				m.logger.Debugf("%s %s: %s", p.Fullname(), outputType, string(line))
+				m.logger.DebugfOp(readFromPipeOp, string(line))
 			}
 		}
 	}
 	go readFromPipe("stdout", processStdOut)
 	go readFromPipe("stderr", processStdErr)
 	if err := cmd.Start(); err != nil {
-		return fmt.Errorf("%s %s with PM2: %v", cmdName, p.Fullname(), err)
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	return nil
 }

internal/pkg/pm2/unoconv.go

@@ -2,6 +2,7 @@ package pm2
 
 import (
 	"github.com/thecodingmachine/gotenberg/internal/pkg/logger"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 type unoconv struct {
@@ -21,11 +22,19 @@ func (p *unoconv) Fullname() string {
 }
 
 func (p *unoconv) Start() error {
-	return p.manager.start(p)
+	const op = "unoconv.Start"
+	if err := p.manager.start(p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }
 
 func (p *unoconv) Shutdown() error {
-	return p.manager.shutdown(p)
+	const op = "unoconv.Shutdown"
+	if err := p.manager.shutdown(p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }
 
 func (p *unoconv) args() []string {

internal/pkg/standarderror/doc.go

@@ -1,5 +1,7 @@
-// Package standarderror helps standardizing
+/*
-// the errors in the application.
+Package standarderror helps standardizing
-//
+the errors in the application.
-// Credits: https://middlemost.com/failure-is-your-domain/
+
+Credits: https://middlemost.com/failure-is-your-domain/
+*/
 package standarderror

internal/pkg/standarderror/standarderror.go

@@ -35,10 +35,6 @@ type Error struct {
 // Error returns the string representation of the error message.
 func (err *Error) Error() string {
 	var buf bytes.Buffer
-	// print the current operation in our stack, if any.
-	if err.Op != "" {
-		fmt.Fprintf(&buf, "%s: ", err.Op)
-	}
 	// if wrapping an error, print its Error() message.
 	// Otherwise print the error code & message.
 	if err.Err != nil {
@@ -83,3 +79,31 @@ func Message(err error) string {
 	}
 	return "An internal error has occurred. Please contact technical support."
 }
+
+// Op returns the logical operation of the error, if available.
+// Otherwise returns an empty string.
+// FIXME: "resource.ChromePrinterOptions: float64: : "
+func Op(err error) string {
+	if err == nil {
+		return ""
+	}
+	e, ok := err.(*Error)
+	if !ok {
+		return ""
+	}
+	var buf bytes.Buffer
+	if e.Op != "" {
+		fmt.Fprintf(&buf, "%s: ", e.Op)
+	}
+	if e.Err != nil {
+		if wrappedOp := Op(e.Err); wrappedOp != "" {
+			fmt.Fprintf(&buf, "%s: ", wrappedOp)
+		}
+	}
+	return buf.String()
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = error(new(Error))
+)