Added log formats and support methods. (#3)

.github/workflows/test.yaml

@@ -0,0 +1,25 @@
+name: Test
+
+on: push
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v2
+
+      - name: Checkout actions repository
+        uses: actions/checkout@v2
+        with:
+          repository: msales/github-actions
+          ref: master
+          token: ${{ secrets.GH_TOKEN }}
+          path: .github/actions/external
+
+      - name: Run the tests
+        id: test
+        uses: ./.github/actions/external/go-test
+        with:
+          org_token: ${{ secrets.GH_TOKEN }}

Dockerfile

@@ -0,0 +1,17 @@
+FROM msales/go-builder:1.15-base-1.0.0 as builder
+
+# This image only serves testing purposes.
+
+# Set token
+ARG GITHUB_TOKEN
+RUN git config --global url."https://${GITHUB_TOKEN}@github.com/".insteadOf "https://github.com/"
+
+WORKDIR /app
+
+COPY ./ .
+
+ENV GOPRIVATE github.com/msales
+ENV GO111MODULE on
+
+# It's a library. Build will only check if the code can be compiled successfully.
+RUN go build -v ./...

go.mod

@@ -1,7 +1,10 @@
 module github.com/msales/logged
 
+go 1.15
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/stretchr/testify v1.2.2
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
 )

go.sum

@@ -4,3 +4,5 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

logger.go

@@ -1,8 +1,9 @@
 package logged
 
 import (
-	"errors"
 	"io"
+
+	"golang.org/x/xerrors"
 )
 
 const errorKey = "LOGGED_ERROR"
@@ -33,7 +34,7 @@ func LevelFromString(lvl string) (Level, error) {
 	case "crit":
 		return Crit, nil
 	default:
-		return 0, errors.New("unknown level " + lvl)
+		return 0, xerrors.Errorf("log: invalid log level: %s", lvl)
 	}
 }
 
@@ -55,6 +56,39 @@ func (l Level) String() string {
 	}
 }
 
+// List of predefined log Formats
+const (
+	JSON Format = iota
+	Logfmt
+)
+
+// Format represents the predefined log format.
+type Format int
+
+// FormatterFromString returns a formatter instance appropriate for the given format name.
+func FormatterFromString(format string) (Formatter, error) {
+	switch format {
+	case "json":
+		return JSONFormat(), nil
+	case "logfmt":
+		return LogfmtFormat(), nil
+	default:
+		return nil, xerrors.Errorf("log: invalid log format: %s", format)
+	}
+}
+
+// String returns the string representation of the level.
+func (f Format) String() string {
+	switch f {
+	case JSON:
+		return "json"
+	case Logfmt:
+		return "logfmt"
+	default:
+		return "unkn"
+	}
+}
+
 // Logger represents a log writer.
 type Logger interface {
 	// Debug logs a debug message.

logger_test.go

@@ -65,7 +65,7 @@ func TestLevelFromString(t *testing.T) {
 			}
 
 			assert.NoError(t, err)
-			assert.Equal(t, tt.want, lvl, )
+			assert.Equal(t, tt.want, lvl)
 		})
 	}
 }
@@ -106,6 +106,64 @@ func TestLevel_String(t *testing.T) {
 	}
 }
 
+func TestFormatterFromString(t *testing.T) {
+	tests := []struct {
+		format    string
+		wantError bool
+	}{
+		{
+			format:    "json",
+			wantError: false,
+		},
+		{
+			format:    "logfmt",
+			wantError: false,
+		},
+		{
+			format:    "unkn",
+			wantError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.format, func(t *testing.T) {
+			format, err := logged.FormatterFromString(tt.format)
+
+			if tt.wantError {
+				assert.Error(t, err)
+				return
+			}
+
+			assert.NoError(t, err)
+			assert.IsType(t, logged.FormatterFunc(nil), format)
+		})
+	}
+}
+
+func TestFormat_String(t *testing.T) {
+	tests := []struct {
+		format logged.Format
+		want   string
+	}{
+		{
+			format: logged.JSON,
+			want:   "json",
+		},
+		{
+			format: logged.Logfmt,
+			want:   "logfmt",
+		},
+		{
+			format: logged.Format(123),
+			want:   "unkn",
+		},
+	}
+
+	for _, tt := range tests {
+		assert.Equal(t, tt.want, tt.format.String())
+	}
+}
+
 func TestNew(t *testing.T) {
 	h := logged.HandlerFunc(func(msg string, lvl logged.Level, ctx []interface{}) {})