feat: use slog instead of zap for structured logging

slog is part of the standard library, so prefer to remove the zap
dependency.

cmd/ssh-portal-api/main.go

@@ -1,9 +1,11 @@
-// Package main is the executable ssh-portal-api service.
+// Package main implements the ssh-portal-api service.
 package main
 
 import (
+	"log/slog"
+	"os"
+
 	"github.com/alecthomas/kong"
-	"go.uber.org/zap"
 )
 
 // CLI represents the command-line interface.
@@ -20,13 +22,13 @@ func main() {
 		kong.UsageOnError(),
 	)
 	// init logger
-	var log *zap.Logger
+	var log *slog.Logger
 	if cli.Debug {
-		log = zap.Must(zap.NewDevelopment(zap.AddStacktrace(zap.ErrorLevel)))
+		log = slog.New(slog.NewJSONHandler(os.Stderr,
+			&slog.HandlerOptions{Level: slog.LevelDebug}))
 	} else {
-		log = zap.Must(zap.NewProduction())
+		log = slog.New(slog.NewJSONHandler(os.Stderr, nil))
 	}
-	defer log.Sync() //nolint:errcheck
 	// execute CLI
 	kctx.FatalIfErrorf(kctx.Run(log))
 }

cmd/ssh-portal-api/serve.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"os/signal"
 	"syscall"
 
@@ -12,7 +13,6 @@ import (
 	"github.com/uselagoon/ssh-portal/internal/metrics"
 	"github.com/uselagoon/ssh-portal/internal/rbac"
 	"github.com/uselagoon/ssh-portal/internal/sshportalapi"
-	"go.uber.org/zap"
 )
 
 // ServeCmd represents the serve command.
@@ -29,7 +29,7 @@ type ServeCmd struct {
 }
 
 // Run the serve command to ssh-portal API requests.
-func (cmd *ServeCmd) Run(log *zap.Logger) error {
+func (cmd *ServeCmd) Run(log *slog.Logger) error {
 	// metrics needs a separate context because deferred Shutdown() will exit
 	// immediately the context is done, which is the case for ctx on SIGTERM.
 	m := metrics.NewServer(log, ":9911")

cmd/ssh-portal/main.go

@@ -1,10 +1,12 @@
-// Package main implements the ssh-portal executable.
+// Package main implements the ssh-portal service.
 package main
 
 import (
+	"log/slog"
+	"os"
+
 	"github.com/alecthomas/kong"
 	"github.com/moby/spdystream"
-	"go.uber.org/zap"
 )
 
 // CLI represents the command-line interface.
@@ -23,13 +25,13 @@ func main() {
 		kong.UsageOnError(),
 	)
 	// init logger
-	var log *zap.Logger
+	var log *slog.Logger
 	if cli.Debug {
-		log = zap.Must(zap.NewDevelopment(zap.AddStacktrace(zap.ErrorLevel)))
+		log = slog.New(slog.NewJSONHandler(os.Stderr,
+			&slog.HandlerOptions{Level: slog.LevelDebug}))
 	} else {
-		log = zap.Must(zap.NewProduction())
+		log = slog.New(slog.NewJSONHandler(os.Stderr, nil))
 	}
-	defer log.Sync() //nolint:errcheck
 	// execute CLI
 	kctx.FatalIfErrorf(kctx.Run(log))
 }

cmd/ssh-portal/serve.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"net"
 	"os/signal"
 	"syscall"
@@ -11,7 +12,6 @@ import (
 	"github.com/uselagoon/ssh-portal/internal/k8s"
 	"github.com/uselagoon/ssh-portal/internal/metrics"
 	"github.com/uselagoon/ssh-portal/internal/sshserver"
-	"go.uber.org/zap"
 )
 
 // ServeCmd represents the serve command.
@@ -25,7 +25,7 @@ type ServeCmd struct {
 }
 
 // Run the serve command to handle SSH connection requests.
-func (cmd *ServeCmd) Run(log *zap.Logger) error {
+func (cmd *ServeCmd) Run(log *slog.Logger) error {
 	// metrics needs a separate context because deferred Shutdown() will exit
 	// immediately the context is done, which is the case for ctx on SIGTERM.
 	m := metrics.NewServer(log, ":9912")
@@ -42,10 +42,10 @@ func (cmd *ServeCmd) Run(log *zap.Logger) error {
 			stop()
 		}),
 		nats.DisconnectErrHandler(func(_ *nats.Conn, err error) {
-			log.Warn("nats disconnected", zap.Error(err))
+			log.Warn("nats disconnected", slog.Any("error", err))
 		}),
 		nats.ReconnectHandler(func(nc *nats.Conn) {
-			log.Info("nats reconnected", zap.String("url", nc.ConnectedUrl()))
+			log.Info("nats reconnected", slog.String("url", nc.ConnectedUrl()))
 		}))
 	if err != nil {
 		return fmt.Errorf("couldn't connect to NATS server: %v", err)

cmd/ssh-token/main.go

@@ -1,9 +1,11 @@
-// Package main is the executable ssh-token service.
+// Package main implements the ssh-token service.
 package main
 
 import (
+	"log/slog"
+	"os"
+
 	"github.com/alecthomas/kong"
-	"go.uber.org/zap"
 )
 
 // CLI represents the command-line interface.
@@ -20,13 +22,13 @@ func main() {
 		kong.UsageOnError(),
 	)
 	// init logger
-	var log *zap.Logger
+	var log *slog.Logger
 	if cli.Debug {
-		log = zap.Must(zap.NewDevelopment(zap.AddStacktrace(zap.ErrorLevel)))
+		log = slog.New(slog.NewJSONHandler(os.Stderr,
+			&slog.HandlerOptions{Level: slog.LevelDebug}))
 	} else {
-		log = zap.Must(zap.NewProduction())
+		log = slog.New(slog.NewJSONHandler(os.Stderr, nil))
 	}
-	defer log.Sync() //nolint:errcheck
 	// execute CLI
 	kctx.FatalIfErrorf(kctx.Run(log))
 }

cmd/ssh-token/serve.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"net"
 	"os/signal"
 	"syscall"
@@ -13,7 +14,6 @@ import (
 	"github.com/uselagoon/ssh-portal/internal/metrics"
 	"github.com/uselagoon/ssh-portal/internal/rbac"
 	"github.com/uselagoon/ssh-portal/internal/sshtoken"
-	"go.uber.org/zap"
 )
 
 // ServeCmd represents the serve command.
@@ -35,7 +35,7 @@ type ServeCmd struct {
 }
 
 // Run the serve command to ssh-portal API requests.
-func (cmd *ServeCmd) Run(log *zap.Logger) error {
+func (cmd *ServeCmd) Run(log *slog.Logger) error {
 	// metrics needs a separate context because deferred Shutdown() will exit
 	// immediately the context is done, which is the case for ctx on SIGTERM.
 	m := metrics.NewServer(log, ":9948")

go.mod

@@ -16,7 +16,6 @@ require (
 	github.com/prometheus/client_golang v1.18.0
 	github.com/zitadel/oidc/v3 v3.10.0
 	go.opentelemetry.io/otel v1.21.0
-	go.uber.org/zap v1.26.0
 	golang.org/x/crypto v0.18.0
 	golang.org/x/exp v0.0.0-20230817173708-d852ddb80c63
 	golang.org/x/oauth2 v0.16.0
@@ -68,7 +67,6 @@ require (
 	github.com/zitadel/schema v1.3.0 // indirect
 	go.opentelemetry.io/otel/metric v1.21.0 // indirect
 	go.opentelemetry.io/otel/trace v1.21.0 // indirect
-	go.uber.org/multierr v1.10.0 // indirect
 	golang.org/x/net v0.20.0 // indirect
 	golang.org/x/sys v0.16.0 // indirect
 	golang.org/x/term v0.16.0 // indirect

go.sum

@@ -168,12 +168,6 @@ go.opentelemetry.io/otel/metric v1.21.0 h1:tlYWfeo+Bocx5kLEloTjbcDwBuELRrIFxwdQ3
 go.opentelemetry.io/otel/metric v1.21.0/go.mod h1:o1p3CA8nNHW8j5yuQLdc1eeqEaPfzug24uvsyIEJRWM=
 go.opentelemetry.io/otel/trace v1.21.0 h1:WD9i5gzvoUPuXIXH24ZNBudiarZDKuekPqi/E8fpfLc=
 go.opentelemetry.io/otel/trace v1.21.0/go.mod h1:LGbsEB0f9LGjN+OZaQQ26sohbOmiMR+BaslueVtS/qQ=
-go.uber.org/goleak v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
-go.uber.org/goleak v1.2.0/go.mod h1:XJYK+MuIchqpmGmUSAzotztawfKvYLUIgg7guXrwVUo=
-go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
-go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-go.uber.org/zap v1.26.0 h1:sI7k6L95XOKS281NhVKOFCUNIvv9e0w4BF8N3u+tCRo=
-go.uber.org/zap v1.26.0/go.mod h1:dtElttAiwGvoJ/vj4IwHBS/gXsEu/pZ50mUIRWuG0so=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=

internal/keycloak/client.go

@@ -5,13 +5,12 @@ package keycloak
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"path"
 	"time"
 
-	"go.uber.org/zap"
-
 	"github.com/MicahParks/keyfunc/v2"
 	oidcClient "github.com/zitadel/oidc/v3/pkg/client"
 	"github.com/zitadel/oidc/v3/pkg/oidc"
@@ -24,12 +23,12 @@ type Client struct {
 	clientID     string
 	clientSecret string
 	jwks         *keyfunc.JWKS
-	log          *zap.Logger
+	log          *slog.Logger
 	oidcConfig   *oidc.DiscoveryConfiguration
 }
 
 // NewClient creates a new keycloak client for the lagoon realm.
-func NewClient(ctx context.Context, log *zap.Logger, keycloakURL, clientID,
+func NewClient(ctx context.Context, log *slog.Logger, keycloakURL, clientID,
 	clientSecret string) (*Client, error) {
 	// discover OIDC config
 	issuerURL, err := url.Parse(keycloakURL)

internal/keycloak/jwt_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -14,7 +15,6 @@ import (
 	"github.com/alecthomas/assert/v2"
 	"github.com/golang-jwt/jwt/v5"
 	"github.com/uselagoon/ssh-portal/internal/keycloak"
-	"go.uber.org/zap"
 	"golang.org/x/oauth2"
 )
 
@@ -135,7 +135,7 @@ func TestUnmarshalLagoonClaims(t *testing.T) {
 
 func TestValidateTokenClaims(t *testing.T) {
 	// set up logger
-	log := zap.Must(zap.NewDevelopment())
+	log := slog.New(slog.NewJSONHandler(os.Stderr, nil))
 	// set up test cases
 	validClaims := keycloak.LagoonClaims{
 		AuthorizedParty: "auth-server",

internal/metrics/metrics.go

@@ -1,17 +1,18 @@
+// Package metrics implements the prometheus metrics server.
 package metrics
 
 import (
+	"log/slog"
 	"net/http"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"go.uber.org/zap"
 )
 
 // NewServer returns a *http.Server serving prometheus metrics in a new
 // goroutine.
 // Caller should defer Shutdown() for cleanup.
-func NewServer(log *zap.Logger, addr string) *http.Server {
+func NewServer(log *slog.Logger, addr string) *http.Server {
 	mux := http.NewServeMux()
 	mux.Handle("/metrics", promhttp.Handler())
 	s := http.Server{
@@ -22,7 +23,7 @@ func NewServer(log *zap.Logger, addr string) *http.Server {
 	}
 	go func() {
 		if err := s.ListenAndServe(); err != http.ErrServerClosed {
-			log.Error("metrics server did not shut down cleanly", zap.Error(err))
+			log.Error("metrics server did not shut down cleanly", slog.Any("error", err))
 		}
 	}()
 	return &s

internal/sshportalapi/server.go

@@ -5,13 +5,13 @@ package sshportalapi
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"sync"
 
 	"github.com/google/uuid"
 	"github.com/nats-io/nats.go"
 	"github.com/uselagoon/ssh-portal/internal/lagoondb"
 	"github.com/uselagoon/ssh-portal/internal/rbac"
-	"go.uber.org/zap"
 )
 
 const (
@@ -31,7 +31,7 @@ type KeycloakService interface {
 }
 
 // ServeNATS sshportalapi NATS requests.
-func ServeNATS(ctx context.Context, stop context.CancelFunc, log *zap.Logger,
+func ServeNATS(ctx context.Context, stop context.CancelFunc, log *slog.Logger,
 	p *rbac.Permission, l LagoonDBService, k KeycloakService, natsURL string) error {
 	// setup synchronisation
 	wg := sync.WaitGroup{}
@@ -46,10 +46,10 @@ func ServeNATS(ctx context.Context, stop context.CancelFunc, log *zap.Logger,
 			wg.Done()
 		}),
 		nats.DisconnectErrHandler(func(_ *nats.Conn, err error) {
-			log.Warn("nats disconnected", zap.Error(err))
+			log.Warn("nats disconnected", slog.Any("error", err))
 		}),
 		nats.ReconnectHandler(func(nc *nats.Conn) {
-			log.Info("nats reconnected", zap.String("url", nc.ConnectedUrl()))
+			log.Info("nats reconnected", slog.String("url", nc.ConnectedUrl()))
 		}))
 	if err != nil {
 		return fmt.Errorf("couldn't connect to NATS server: %v", err)
@@ -69,7 +69,7 @@ func ServeNATS(ctx context.Context, stop context.CancelFunc, log *zap.Logger,
 	<-ctx.Done()
 	// drain and log errors
 	if err := nc.Drain(); err != nil {
-		log.Warn("couldn't drain connection", zap.Error(err))
+		log.Warn("couldn't drain connection", slog.Any("error", err))
 	}
 	// wait for connection to close
 	wg.Wait()