better op names + fixing issue with op chaining in errors

internal/app/api/pkg/handler/handler.go

@@ -35,10 +35,7 @@ const (
 )
 
 func convert(ctx *context.Context, p printer.Printer) error {
-	const (
+	const op = "handler.convert"
-		op      = "convert"
-		debugOp = "handler.convert"
-	)
 	r := ctx.Resource()
 	logger := ctx.StandardLogger()
 	baseFilename := random.Get()
@@ -48,7 +45,7 @@ func convert(ctx *context.Context, p printer.Printer) error {
 	// and directly return the resulting PDF file
 	// or an error.
 	if !r.Has(resource.WebhookURLFormField) {
-		logger.DebugfOp(debugOp, "no '%s' found, converting synchronously", resource.WebhookURLFormField)
+		logger.DebugfOp(op, "no '%s' found, converting synchronously", resource.WebhookURLFormField)
 		if err := convertSync(filename, fpath, ctx, p); err != nil {
 			return &standarderror.Error{Op: op, Err: err}
 		}
@@ -57,15 +54,12 @@ func convert(ctx *context.Context, p printer.Printer) error {
 	// as a webhook URL has been given, we
 	// run the following lines in a goroutine so that
 	// it doesn't block.
-	logger.DebugfOp(debugOp, "'%s' found, converting asynchronously", resource.WebhookURLFormField)
+	logger.DebugfOp(op, "'%s' found, converting asynchronously", resource.WebhookURLFormField)
 	return convertAsync(filename, fpath, ctx, p)
 }
 
 func convertSync(filename, fpath string, ctx *context.Context, p printer.Printer) error {
-	const (
+	const op = "handler.convertSync"
-		op      = "convertSync"
-		debugOp = "handler.convertSync"
-	)
 	r := ctx.Resource()
 	logger := ctx.StandardLogger()
 	if err := p.Print(fpath); err != nil {
@@ -73,7 +67,7 @@ func convertSync(filename, fpath string, ctx *context.Context, p printer.Printer
 	}
 	if !r.Has(resource.ResultFilenameFormField) {
 		logger.DebugfOp(
-			debugOp,
+			op,
 			"no '%s' found, using generated filename '%s'",
 			resource.ResultFilenameFormField,
 			filename,
@@ -84,7 +78,7 @@ func convertSync(filename, fpath string, ctx *context.Context, p printer.Printer
 		return nil
 	}
 	logger.DebugfOp(
-		debugOp,
+		op,
 		"'%s' found, so not using generated filename",
 		resource.ResultFilenameFormField,
 	)
@@ -99,10 +93,7 @@ func convertSync(filename, fpath string, ctx *context.Context, p printer.Printer
 }
 
 func convertAsync(filename, fpath string, ctx *context.Context, p printer.Printer) error {
-	const (
+	const op = "handler.convertAsync"
-		op      = "convertAsync"
-		debugOp = "handler.convertAsync"
-	)
 	r := ctx.Resource()
 	logger := ctx.StandardLogger()
 	go func() {
@@ -132,7 +123,7 @@ func convertAsync(filename, fpath string, ctx *context.Context, p printer.Printe
 			return
 		}
 		logger.DebugfOp(
-			debugOp,
+			op,
 			"sending result file '%s' to '%s'",
 			filename,
 			webhookURL,

internal/app/api/pkg/handler/html.go

@@ -4,21 +4,26 @@ import (
 	"github.com/labstack/echo/v4"
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/printer"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 // HTML is the endpoint for converting
 // HTML to PDF.
 func HTML(c echo.Context) error {
+	const op = "handler.HTML"
 	ctx := context.MustCastFromEchoContext(c)
 	r := ctx.Resource()
 	opts, err := r.ChromePrinterOptions()
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	fpath, err := r.Fpath("index.html")
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p := printer.NewHTML(fpath, opts)
-	return convert(ctx, p)
+	if err := convert(ctx, p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }

internal/app/api/pkg/handler/markdown.go

@@ -4,24 +4,29 @@ import (
 	"github.com/labstack/echo/v4"
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/printer"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 // Markdown is the endpoint for converting
 // Markdown to PDF.
 func Markdown(c echo.Context) error {
+	const op = "handler.Markdown"
 	ctx := context.MustCastFromEchoContext(c)
 	r := ctx.Resource()
 	opts, err := r.ChromePrinterOptions()
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	fpath, err := r.Fpath("index.html")
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p, err := printer.NewMarkdown(fpath, opts)
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
-	return convert(ctx, p)
+	if err := convert(ctx, p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }

internal/app/api/pkg/handler/merge.go

@@ -4,21 +4,26 @@ import (
 	"github.com/labstack/echo/v4"
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/printer"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 // Merge is the endpoint for
 // merging PDF files.
 func Merge(c echo.Context) error {
+	const op = "handler.Merge"
 	ctx := context.MustCastFromEchoContext(c)
 	r := ctx.Resource()
 	opts, err := r.MergePrinterOptions()
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	fpaths, err := r.Fpaths(".pdf")
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p := printer.NewMerge(fpaths, opts)
-	return convert(ctx, p)
+	if err := convert(ctx, p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }

internal/app/api/pkg/handler/office.go

@@ -4,16 +4,18 @@ import (
 	"github.com/labstack/echo/v4"
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/printer"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 // Office is the endpoint for converting
 // Office files to PDF.
 func Office(c echo.Context) error {
+	const op = "handler.Office"
 	ctx := context.MustCastFromEchoContext(c)
 	r := ctx.Resource()
 	opts, err := r.OfficePrinterOptions()
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	fpaths, err := r.Fpaths(
 		".txt",
@@ -30,8 +32,11 @@ func Office(c echo.Context) error {
 		".odp",
 	)
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p := printer.NewOffice(fpaths, opts)
-	return convert(ctx, p)
+	if err := convert(ctx, p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }

internal/app/api/pkg/handler/url.go

@@ -5,21 +5,26 @@ import (
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
 	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/resource"
 	"github.com/thecodingmachine/gotenberg/internal/pkg/printer"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
 )
 
 // URL is the endpoint for converting
 // a URL to PDF.
 func URL(c echo.Context) error {
+	const op = "handler.URL"
 	ctx := context.MustCastFromEchoContext(c)
 	r := ctx.Resource()
 	opts, err := r.ChromePrinterOptions()
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	remoteURL, err := r.Get(resource.RemoteURLFormField)
 	if err != nil {
-		return err
+		return &standarderror.Error{Op: op, Err: err}
 	}
 	p := printer.NewURL(remoteURL, opts)
-	return convert(ctx, p)
+	if err := convert(ctx, p); err != nil {
+		return &standarderror.Error{Op: op, Err: err}
+	}
+	return nil
 }

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

@@ -83,7 +83,7 @@ func New(c echo.Context, logger *logger.Logger, config *config.Config, dirPath s
 }
 
 func formValues(c echo.Context, logger *logger.Logger) map[string]string {
-	const debugOp = "resource.formValues"
+	const op = "resource.formValues"
 	v := make(map[string]string)
 	v[ResultFilenameFormField] = c.FormValue(ResultFilenameFormField)
 	v[WaitTimeoutFormField] = c.FormValue(WaitTimeoutFormField)
@@ -97,15 +97,12 @@ func formValues(c echo.Context, logger *logger.Logger) map[string]string {
 	v[MarginLeftFormField] = c.FormValue(MarginLeftFormField)
 	v[MarginRightFormField] = c.FormValue(MarginRightFormField)
 	v[LandscapeFormField] = c.FormValue(LandscapeFormField)
-	logger.DebugfOp(debugOp, "%v", v)
+	logger.DebugfOp(op, "%v", v)
 	return v
 }
 
 func formFiles(c echo.Context, logger *logger.Logger, dirPath string) error {
-	const (
+	const op = "resource.formFiles"
-		op      = "formFiles"
-		debugOp = "resource.formFiles"
-	)
 	form, err := c.MultipartForm()
 	if err != nil {
 		return &standarderror.Error{Op: op, Err: err}
@@ -132,7 +129,7 @@ func formFiles(c echo.Context, logger *logger.Logger, dirPath string) error {
 			if _, err := out.Seek(0, 0); err != nil {
 				return &standarderror.Error{Op: op, Err: err}
 			}
-			logger.DebugfOp(debugOp, "'%s' created", fh.Filename)
+			logger.DebugfOp(op, "'%s' created", fh.Filename)
 		}
 	}
 	return nil
@@ -293,7 +290,7 @@ func (r *Resource) Get(formField string) (string, error) {
 }
 
 func (r *Resource) value(formField string) (string, error) {
-	const op = "value"
+	const op = "resource.value"
 	v, ok := r.formValues[formField]
 	if !ok {
 		return "", &standarderror.Error{
@@ -306,7 +303,7 @@ func (r *Resource) value(formField string) (string, error) {
 }
 
 func (r *Resource) float64(formField string, defaultValue float64) (float64, error) {
-	const op = "float64"
+	const op = "resource.float64"
 	if !r.Has(formField) {
 		return defaultValue, nil
 	}
@@ -326,7 +323,7 @@ func (r *Resource) float64(formField string, defaultValue float64) (float64, err
 }
 
 func (r *Resource) bool(formField string, defaultValue bool) (bool, error) {
-	const op = "bool"
+	const op = "resource.bool"
 	if !r.Has(formField) {
 		return defaultValue, nil
 	}
@@ -366,7 +363,7 @@ func (r *Resource) Fpath(filename string) (string, error) {
 }
 
 func (r *Resource) content(filename string, defaultValue string) (string, error) {
-	const op = "content"
+	const op = "resource.content"
 	if !r.hasFile(filename) {
 		return defaultValue, nil
 	}
@@ -387,7 +384,7 @@ func (r *Resource) Fpaths(exts ...string) ([]string, error) {
 	const op = "resource.Fpaths"
 	var fpaths []string
 	err := filepath.Walk(r.formFilesDirPath, func(path string, info os.FileInfo, _ error) error {
-		const walkOp = "filepath.Walk"
+		const walkOp = "resource.filepath.Walk"
 		if info.IsDir() {
 			return nil
 		}

internal/pkg/config/config.go

@@ -103,7 +103,7 @@ func (c *Config) LogLevel() logrus.Level {
 }
 
 func defaultWaitTimeoutFromEnv(envVar string, defaultValue float64) (float64, error) {
-	const op = "defaultWaitTimeoutFromEnv"
+	const op = "config.defaultWaitTimeoutFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		waitTimeout, err := strconv.ParseFloat(v, 64)
 		if err != nil {
@@ -119,7 +119,7 @@ func defaultWaitTimeoutFromEnv(envVar string, defaultValue float64) (float64, er
 }
 
 func defaultListenPortFromEnv(envVar string, defaultValue string) (string, error) {
-	const op = "defaultListenPortFromEnv"
+	const op = "config.defaultListenPortFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		portAsUint, err := strconv.ParseUint(v, 10, 64)
 		if err != nil {
@@ -142,7 +142,7 @@ func defaultListenPortFromEnv(envVar string, defaultValue string) (string, error
 }
 
 func boolFromEnv(envVar string, defaultValue bool) (bool, error) {
-	const op = "boolFromEnv"
+	const op = "config.boolFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		if v != "1" && v != "0" {
 			return defaultValue, &standarderror.Error{
@@ -157,7 +157,7 @@ func boolFromEnv(envVar string, defaultValue bool) (bool, error) {
 }
 
 func logLevelFromEnv(envVar string, defaultValue logrus.Level) (logrus.Level, error) {
-	const op = "logLevelFromEnv"
+	const op = "config.logLevelFromEnv"
 	if v, ok := os.LookupEnv(envVar); ok {
 		switch v {
 		case "DEBUG":

internal/pkg/pm2/chrome.go

@@ -28,7 +28,7 @@ func (p *chrome) Fullname() string {
 }
 
 func (p *chrome) Start() error {
-	const op = "chrome.Start"
+	const op = "pm2.chrome.Start"
 	if err := p.manager.start(p); err != nil {
 		return &standarderror.Error{Op: op, Err: err}
 	}
@@ -36,7 +36,7 @@ func (p *chrome) Start() error {
 }
 
 func (p *chrome) Shutdown() error {
-	const op = "chrome.Shutdown"
+	const op = "pm2.chrome.Shutdown"
 	if err := p.manager.shutdown(p); err != nil {
 		return &standarderror.Error{Op: op, Err: err}
 	}
@@ -67,25 +67,25 @@ func (p *chrome) name() string {
 }
 
 func (p *chrome) viable() bool {
-	const debugOp = "chrome.viable"
+	const op = "pm2.chrome.viable"
 	// check if Google Chrome is correctly running.
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	p.manager.logger.DebugfOp(
-		debugOp,
+		op,
 		"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.DebugfOp(
-			debugOp,
+			op,
 			"debug version endpoint returned error: %v",
 			err,
 		)
 		return false
 	}
 	p.manager.logger.DebugfOp(
-		debugOp,
+		op,
 		"debug version endpoint returned version info: %+v",
 		*v,
 	)
@@ -93,7 +93,7 @@ func (p *chrome) viable() bool {
 }
 
 func (p *chrome) warmup() {
-	const debugOp = "chrome.warmup"
+	const debugOp = "pm2.chrome.warmup"
 	p.manager.logger.DebugfOp(
 		debugOp,
 		"allowing %v to startup",

internal/pkg/pm2/unoconv.go

@@ -22,7 +22,7 @@ func (p *unoconv) Fullname() string {
 }
 
 func (p *unoconv) Start() error {
-	const op = "unoconv.Start"
+	const op = "pm2.unoconv.Start"
 	if err := p.manager.start(p); err != nil {
 		return &standarderror.Error{Op: op, Err: err}
 	}
@@ -30,7 +30,7 @@ func (p *unoconv) Start() error {
 }
 
 func (p *unoconv) Shutdown() error {
-	const op = "unoconv.Shutdown"
+	const op = "pm2.unoconv.Shutdown"
 	if err := p.manager.shutdown(p); err != nil {
 		return &standarderror.Error{Op: op, Err: err}
 	}

internal/pkg/standarderror/standarderror.go

@@ -82,7 +82,6 @@ func Message(err error) string {
 
 // 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 ""
@@ -93,12 +92,10 @@ func Op(err error) string {
 	}
 	var buf bytes.Buffer
 	if e.Op != "" {
-		fmt.Fprintf(&buf, "%s: ", e.Op)
+		fmt.Fprintf(&buf, "%s", e.Op)
 	}
-	if e.Err != nil {
+	if nestedOp := Op(e.Err); nestedOp != "" {
-		if wrappedOp := Op(e.Err); wrappedOp != "" {
+		fmt.Fprintf(&buf, ": %s", nestedOp)
-			fmt.Fprintf(&buf, "%s: ", wrappedOp)
-		}
 	}
 	return buf.String()
 }