api/log: initial implementation of the package (smallstep#859)

* api/log: initial implementation of the package

* api: refactored to support api/log

* scep/api: refactored to support api/log

* api/log: documented the package

* api: moved log-related tests to api/log

Author: azazeal

Diff for: api/errors.go

@@ -9,6 +9,7 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/smallstep/certificates/acme"
+	"github.com/smallstep/certificates/api/log"
 	"github.com/smallstep/certificates/authority/admin"
 	"github.com/smallstep/certificates/errs"
 	"github.com/smallstep/certificates/logging"
@@ -60,6 +61,6 @@ func WriteError(w http.ResponseWriter, err error) {
 	}
 
 	if err := json.NewEncoder(w).Encode(err); err != nil {
-		LogError(w, err)
+		log.Error(w, err)
 	}
 }

Diff for: api/log/log.go

@@ -0,0 +1,47 @@
+// Package log implements API-related logging helpers.
+package log
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/smallstep/certificates/logging"
+)
+
+// Error adds to the response writer the given error if it implements
+// logging.ResponseLogger. If it does not implement it, then writes the error
+// using the log package.
+func Error(rw http.ResponseWriter, err error) {
+	if rl, ok := rw.(logging.ResponseLogger); ok {
+		rl.WithFields(map[string]interface{}{
+			"error": err,
+		})
+	} else {
+		log.Println(err)
+	}
+}
+
+// EnabledResponse log the response object if it implements the EnableLogger
+// interface.
+func EnabledResponse(rw http.ResponseWriter, v interface{}) {
+	type enableLogger interface {
+		ToLog() (interface{}, error)
+	}
+
+	if el, ok := v.(enableLogger); ok {
+		out, err := el.ToLog()
+		if err != nil {
+			Error(rw, err)
+
+			return
+		}
+
+		if rl, ok := rw.(logging.ResponseLogger); ok {
+			rl.WithFields(map[string]interface{}{
+				"response": out,
+			})
+		} else {
+			log.Println(out)
+		}
+	}
+}

Diff for: api/log/log_test.go

@@ -0,0 +1,44 @@
+package log
+
+import (
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"testing"
+
+	"github.com/smallstep/certificates/logging"
+)
+
+func TestError(t *testing.T) {
+	theError := errors.New("the error")
+
+	type args struct {
+		rw  http.ResponseWriter
+		err error
+	}
+	tests := []struct {
+		name       string
+		args       args
+		withFields bool
+	}{
+		{"normalLogger", args{httptest.NewRecorder(), theError}, false},
+		{"responseLogger", args{logging.NewResponseLogger(httptest.NewRecorder()), theError}, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			Error(tt.args.rw, tt.args.err)
+			if tt.withFields {
+				if rl, ok := tt.args.rw.(logging.ResponseLogger); ok {
+					fields := rl.Fields()
+					if !reflect.DeepEqual(fields["error"], theError) {
+						t.Errorf("ResponseLogger[\"error\"] = %s, wants %s", fields["error"], theError)
+					}
+				} else {
+					t.Error("ResponseWriter does not implement logging.ResponseLogger")
+				}
+			}
+		})
+	}
+}

Diff for: api/utils.go

@@ -2,52 +2,14 @@ package api
 
 import (
 	"encoding/json"
-	"log"
 	"net/http"
 
 	"google.golang.org/protobuf/encoding/protojson"
 	"google.golang.org/protobuf/proto"
 
-	"github.com/smallstep/certificates/logging"
+	"github.com/smallstep/certificates/api/log"
 )
 
-// EnableLogger is an interface that enables response logging for an object.
-type EnableLogger interface {
-	ToLog() (interface{}, error)
-}
-
-// LogError adds to the response writer the given error if it implements
-// logging.ResponseLogger. If it does not implement it, then writes the error
-// using the log package.
-func LogError(rw http.ResponseWriter, err error) {
-	if rl, ok := rw.(logging.ResponseLogger); ok {
-		rl.WithFields(map[string]interface{}{
-			"error": err,
-		})
-	} else {
-		log.Println(err)
-	}
-}
-
-// LogEnabledResponse log the response object if it implements the EnableLogger
-// interface.
-func LogEnabledResponse(rw http.ResponseWriter, v interface{}) {
-	if el, ok := v.(EnableLogger); ok {
-		out, err := el.ToLog()
-		if err != nil {
-			LogError(rw, err)
-			return
-		}
-		if rl, ok := rw.(logging.ResponseLogger); ok {
-			rl.WithFields(map[string]interface{}{
-				"response": out,
-			})
-		} else {
-			log.Println(out)
-		}
-	}
-}
-
 // JSON writes the passed value into the http.ResponseWriter.
 func JSON(w http.ResponseWriter, v interface{}) {
 	JSONStatus(w, v, http.StatusOK)
@@ -59,10 +21,12 @@ func JSONStatus(w http.ResponseWriter, v interface{}, status int) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
 	if err := json.NewEncoder(w).Encode(v); err != nil {
-		LogError(w, err)
+		log.Error(w, err)
+
 		return
 	}
-	LogEnabledResponse(w, v)
+
+	log.EnabledResponse(w, v)
 }
 
 // ProtoJSON writes the passed value into the http.ResponseWriter.
@@ -78,12 +42,16 @@ func ProtoJSONStatus(w http.ResponseWriter, m proto.Message, status int) {
 
 	b, err := protojson.Marshal(m)
 	if err != nil {
-		LogError(w, err)
+		log.Error(w, err)
+
 		return
 	}
+
 	if _, err := w.Write(b); err != nil {
-		LogError(w, err)
+		log.Error(w, err)
+
 		return
 	}
-	//LogEnabledResponse(w, v)
+
+	// log.EnabledResponse(w, v)
 }

Diff for: api/utils_test.go

@@ -3,46 +3,11 @@ package api
 import (
 	"net/http"
 	"net/http/httptest"
-	"reflect"
 	"testing"
 
-	"github.com/pkg/errors"
-
 	"github.com/smallstep/certificates/logging"
 )
 
-func TestLogError(t *testing.T) {
-	theError := errors.New("the error")
-	type args struct {
-		rw  http.ResponseWriter
-		err error
-	}
-	tests := []struct {
-		name       string
-		args       args
-		withFields bool
-	}{
-		{"normalLogger", args{httptest.NewRecorder(), theError}, false},
-		{"responseLogger", args{logging.NewResponseLogger(httptest.NewRecorder()), theError}, true},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			LogError(tt.args.rw, tt.args.err)
-			if tt.withFields {
-				if rl, ok := tt.args.rw.(logging.ResponseLogger); ok {
-					fields := rl.Fields()
-					if !reflect.DeepEqual(fields["error"], theError) {
-						t.Errorf("ResponseLogger[\"error\"] = %s, wants %s", fields["error"], theError)
-					}
-				} else {
-					t.Error("ResponseWriter does not implement logging.ResponseLogger")
-				}
-			}
-		})
-	}
-}
-
 func TestJSON(t *testing.T) {
 	type args struct {
 		rw http.ResponseWriter

Diff for: scep/api/api.go

@@ -10,14 +10,14 @@ import (
 	"strings"
 
 	"github.com/go-chi/chi"
+	microscep "github.com/micromdm/scep/v2/scep"
+	"github.com/pkg/errors"
+	"go.mozilla.org/pkcs7"
+
 	"github.com/smallstep/certificates/api"
+	"github.com/smallstep/certificates/api/log"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/certificates/scep"
-	"go.mozilla.org/pkcs7"
-
-	"github.com/pkg/errors"
-
-	microscep "github.com/micromdm/scep/v2/scep"
 )
 
 const (
@@ -337,7 +337,7 @@ func formatCapabilities(caps []string) []byte {
 func writeSCEPResponse(w http.ResponseWriter, response SCEPResponse) {
 
 	if response.Error != nil {
-		api.LogError(w, response.Error)
+		log.Error(w, response.Error)
 	}
 
 	if response.Certificate != nil {