Replace viper with go-envconfig for easier parsing, enable github gui…

…ld cache

.github/workflows/build.yaml

@@ -27,13 +27,17 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+
       - name: Log in to the Container registry
         uses: docker/login-action@e92390c5fb421da1463c202d546fed0ec5c39f20 # v3.1.0
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@d70bba72b1f3fd22344832f00baa16ece964efeb # v3.3.0
+
       - name: Extract metadata (tags, labels) for Docker
         id: meta
         uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.1.1
@@ -47,3 +51,6 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+

go.mod

@@ -5,41 +5,26 @@ go 1.22
 require (
 	github.com/coreos/go-oidc/v3 v3.10.0
 	github.com/rs/zerolog v1.32.0
-	github.com/spf13/viper v1.18.1 // 1.18.2 removes automatic bind env variables
 )
 
-require github.com/stretchr/testify v1.8.4
+require (
+	github.com/sethvargo/go-envconfig v1.0.1
+	github.com/stretchr/testify v1.8.4
+)
 
 require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/go-jose/go-jose/v4 v4.0.1 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
-	github.com/google/go-cmp v0.6.0 // indirect
-	github.com/hashicorp/hcl v1.0.0 // indirect
-	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
-	github.com/mitchellh/mapstructure v1.5.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.1.0 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/sagikazarmark/locafero v0.4.0 // indirect
-	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
-	github.com/sourcegraph/conc v0.3.0 // indirect
-	github.com/spf13/afero v1.11.0 // indirect
-	github.com/spf13/cast v1.6.0 // indirect
-	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/subosito/gotenv v1.6.0 // indirect
-	go.uber.org/atomic v1.9.0 // indirect
-	go.uber.org/multierr v1.9.0 // indirect
 	golang.org/x/crypto v0.19.0 // indirect
-	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
 	golang.org/x/oauth2 v0.15.0 // indirect
 	golang.org/x/sys v0.17.0 // indirect
-	golang.org/x/text v0.14.0 // indirect
 	google.golang.org/appengine v1.6.8 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
-	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

main.go

@@ -12,29 +12,37 @@ import (
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 
-	"github.com/spf13/viper"
+	"github.com/sethvargo/go-envconfig"
 )
 
 type Options struct {
-	Issuer       string   `mapstructure:"issuer"`
-	Audience     string   `mapstructure:"audience"`
-	SubjectRegex string   `mapstructure:"subject_regex"`
-	LogLevel     string   `mapstructure:"log_level"`
-	LogPretty    bool     `mapstructure:"log_pretty"`
-	Subjects     []string `mapstructure:"subjects"`
+	Issuer    string   `env:"ISSUER, required"`
+	Audience  string   `env:"AUDIENCE, required"`
+	LogLevel  string   `env:"LOG_LEVEL, default=info"`
+	LogPretty bool     `env:"LOG_PRETTY"`
+	Subjects  []string `env:"SUBJECTS, required"`
 }
 
 func main() {
+	ctx := context.Background()
 	var opts Options
+	err := envconfig.Process(ctx, &opts)
+	initLogger(opts)
+
+	log.Info().Msg("Starting")
+	log.Info().Str("ISSUER", opts.Issuer).Send()
+	log.Info().Str("AUDIENCE", opts.Audience).Send()
+	log.Info().Str("LOG_LEVEL", opts.LogLevel).Send()
+	log.Info().Bool("LOG_PRETTY", opts.LogPretty).Send()
+	log.Info().Strs("SUBJECTS", opts.Subjects).Send()
 
-	viper.AutomaticEnv()
-	if err := viper.Unmarshal(&opts); err != nil {
+	// Print any failures from proccessing ENV here,
+	// se we can see available options
+	if err != nil {
 		log.Fatal().Msg(err.Error())
 	}
 
-	initLogger(opts)
-
-	Run(context.Background(), opts)
+	Run(ctx, opts)
 }
 
 func initLogger(opts Options) {
@@ -60,7 +68,6 @@ func initLogger(opts Options) {
 }
 
 func Run(ctx context.Context, opts Options) {
-	log.Info().Interface("options", opts).Msg("Starting...")
 
 	provider, err := oidc.NewProvider(ctx, opts.Issuer)
 	if err != nil {
@@ -73,13 +80,9 @@ func Run(ctx context.Context, opts Options) {
 	verifier := provider.Verifier(oidcConfig)
 
 	authHandler := AuthHandler(opts.Subjects, verifier)
-	http.Handle("POST /auth", authHandler)
-	http.Handle("GET /", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(404)
-		_, _ = w.Write([]byte("404 Not Found"))
-	}))
+	http.Handle("/auth", authHandler)
 
-	log.Info().Msg("Starting server on :8000...")
+	log.Info().Msg("Listening on http://localhost:8000...")
 	err = http.ListenAndServe(":8000", nil)
 	if err != nil && !errors.Is(err, http.ErrServerClosed) {
 		log.Fatal().Err(err).Msgf("listen: %s", err)