feat: add slog logging (#432)

* feat(op): user slog for logging

integrate with golang.org/x/exp/slog for logging.
provide a middleware for request scoped logging.

BREAKING CHANGES:

1. OpenIDProvider and sub-interfaces get a Logger()
method to return the configured logger;
2. AuthRequestError now takes the complete Authorizer,
instead of only the encoder. So that it may use its Logger() method.
3. RequestError now takes a Logger as argument.

* use zitadel/logging

* finish op and testing
without middleware for now

* minimum go version 1.19

* update go mod

* log value testing only on go 1.20 or later

* finish the RP and example

* ping logging release

pkg/oidc/error_test.go

@@ -0,0 +1,81 @@
+package oidc
+
+import (
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/exp/slog"
+)
+
+func TestDefaultToServerError(t *testing.T) {
+	type args struct {
+		err         error
+		description string
+	}
+	tests := []struct {
+		name string
+		args args
+		want *Error
+	}{
+		{
+			name: "default",
+			args: args{
+				err:         io.ErrClosedPipe,
+				description: "oops",
+			},
+			want: &Error{
+				ErrorType:   ServerError,
+				Description: "oops",
+				Parent:      io.ErrClosedPipe,
+			},
+		},
+		{
+			name: "our Error",
+			args: args{
+				err:         ErrAccessDenied(),
+				description: "oops",
+			},
+			want: &Error{
+				ErrorType:   AccessDenied,
+				Description: "The authorization request was denied.",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DefaultToServerError(tt.args.err, tt.args.description)
+			assert.ErrorIs(t, got, tt.want)
+		})
+	}
+}
+
+func TestError_LogLevel(t *testing.T) {
+	tests := []struct {
+		name string
+		err  *Error
+		want slog.Level
+	}{
+		{
+			name: "server error",
+			err:  ErrServerError(),
+			want: slog.LevelError,
+		},
+		{
+			name: "authorization pending",
+			err:  ErrAuthorizationPending(),
+			want: slog.LevelInfo,
+		},
+		{
+			name: "some other error",
+			err:  ErrAccessDenied(),
+			want: slog.LevelWarn,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.err.LogLevel()
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}