cfg and cfg.New

examples/logloglog/main.go

@@ -0,0 +1,67 @@
+// Package main shows an example of logging with sabot.
+package main
+
+import (
+	"context"
+	"os"
+
+	"github.com/pkg/errors"
+
+	"github.com/clarktrimble/sabot"
+)
+
+var (
+	version string
+)
+
+type Config struct {
+	Version string        `json:"version"`
+	Logger  *sabot.Config `json:"logger"`
+}
+
+func main() {
+
+	// usually load config via launch(envconfig), but literal for demo
+
+	cfg := &Config{
+		Version: version,
+		Logger: &sabot.Config{
+			MaxLen: 99,
+		},
+	}
+
+	// create logger
+
+	lgr := cfg.Logger.New(os.Stderr)
+
+	// usually set run id with hondo(rand), but literal for demo
+
+	ctx := lgr.WithFields(context.Background(), "run_id", "123123123")
+
+	// log stuff, yay
+
+	lgr.Info(ctx, "logloglog starting", "config", cfg)
+	lgr.Error(ctx, "failed to, you know ..", errors.Errorf("oops"))
+}
+
+// output:
+
+/*
+$ bin/logloglog 2>&1 | jq --slurp
+[
+  {
+    "config": "{\"version\":\"config.11.8a5e577\",\"logger\":{\"max_len\":99}}",
+    "level": "info",
+    "msg": "logloglog starting",
+    "run_id": "123123123",
+    "ts": "2023-11-25T21:20:54.758434441Z"
+  },
+  {
+    "error": "oops\nmain.main\n\t/home/trimble/proj/sabot/examples/logloglog/main.go:38\nruntime.main\n\t/--truncated--",
+    "level": "error",
+    "msg": "failed to, you know ..",
+    "run_id": "123123123",
+    "ts": "2023-11-25T21:20:54.758722223Z"
+  }
+]
+*/

sabot.go

@@ -12,9 +12,28 @@ import (
 	"github.com/pkg/errors"
 )
 
+const (
+	logErrorKey      string = "logerror"
+	truncationNotice string = "--truncated--"
+)
+
 // Fields are key-value pairs.
 type Fields map[string]any
 
+// Config is the configurable fields of Sabot.
+type Config struct {
+	MaxLen int `json:"max_len" desc:"maximum length that will be logged for any field"`
+}
+
+// New creates a Sabot from Config.
+func (cfg *Config) New(writer io.Writer) *Sabot {
+
+	return &Sabot{
+		MaxLen: cfg.MaxLen,
+		Writer: writer,
+	}
+}
+
 // LogKey is a unique to this package key for use with context Value.
 type LogKey struct{}
 
@@ -57,11 +76,6 @@ func (sabot *Sabot) GetFields(ctx context.Context) Fields {
 // unexported
 //
 
-const (
-	logErrorKey      string = "logerror"
-	truncationNotice string = "--truncated--"
-)
-
 func (sabot *Sabot) log(ctx context.Context, level, msg string, kv []any) {
 
 	now := time.Now().UTC()
@@ -193,6 +207,9 @@ func copyFields(ctx context.Context) Fields {
 
 func (fields Fields) truncate(max int) {
 
+	// Todo: prolly don't want just add notice yeah?
+	// Todo: and while you're up, git rid of alt writer?
+
 	max -= len(truncationNotice)
 	if max < 1 {
 		return

sabot_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"os"
 	"strings"
 	"testing"
 	"time"
@@ -22,16 +23,42 @@ func TestSabot(t *testing.T) {
 
 var _ = Describe("Sabot", func() {
 
+	var (
+		ctx context.Context
+		lgr *Sabot
+	)
+
+	Describe("creating a logger from config", func() {
+		var (
+			cfg *Config
+		)
+
+		JustBeforeEach(func() {
+			lgr = cfg.New(os.Stderr)
+		})
+
+		When("all is well", func() {
+			BeforeEach(func() {
+				cfg = &Config{
+					MaxLen: 99,
+				}
+			})
+
+			It("should setup the logger", func() {
+				Expect(lgr.MaxLen).To(Equal(99))
+				Expect(lgr.Writer).To(Equal(os.Stderr))
+			})
+		})
+	})
+
 	Describe("getting and storing fields", func() {
 		var (
-			ctx    context.Context
 			fields Fields
-			lgr    Sabot
 		)
 
 		BeforeEach(func() {
 			ctx = context.Background()
-			lgr = Sabot{
+			lgr = &Sabot{
 				MaxLen: 0,
 			}
 		})
@@ -99,16 +126,14 @@ var _ = Describe("Sabot", func() {
 		Describe("logging an event", func() {
 			var (
 				buf *bytes.Buffer
-				ctx context.Context
 				msg string
 				err error
 				kv  []any
-				lgr Sabot
 			)
 
 			BeforeEach(func() {
 				buf = &bytes.Buffer{}
-				lgr = Sabot{
+				lgr = &Sabot{
 					Writer: buf,
 					MaxLen: 0,
 				}
@@ -326,6 +351,7 @@ var _ = Describe("Sabot", func() {
 func delog(buf *bytes.Buffer) (logged Fields) {
 
 	// Todo: combine efforts with other log testing stuffs
+
 	// marshal logged data to map
 
 	logged = Fields{}