feat(api): add OIDC bearer token authentication

pkg/modules/api/api_test.go

@@ -0,0 +1,67 @@
+package api
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestApi_Validate_Auth(t *testing.T) {
+	base := func() *Api {
+		return &Api{port: 3000, rootPath: "/", correlationIdHeader: "Gotenberg-Trace"}
+	}
+
+	for _, tc := range []struct {
+		scenario string
+		mutate   func(*Api)
+		wantErr  string // substring expected in the error, "" means no error
+	}{
+		{"no auth", func(*Api) {}, ""},
+		{"basic auth only", func(a *Api) { a.basicAuthUsername = "foo" }, ""},
+		{
+			"oidc auth valid",
+			func(a *Api) {
+				a.oidcEnabled = true
+				a.oidcIssuer = "https://tenant.example.com/"
+				a.oidcAudience = "gotenberg"
+			},
+			"",
+		},
+		{
+			"basic and oidc are mutually exclusive",
+			func(a *Api) {
+				a.basicAuthUsername = "foo"
+				a.oidcEnabled = true
+				a.oidcIssuer = "https://tenant.example.com/"
+				a.oidcAudience = "gotenberg"
+			},
+			"cannot both be enabled",
+		},
+		{
+			"oidc missing issuer",
+			func(a *Api) { a.oidcEnabled = true; a.oidcAudience = "gotenberg" },
+			"issuer must not be empty",
+		},
+		{
+			"oidc missing audience",
+			func(a *Api) { a.oidcEnabled = true; a.oidcIssuer = "https://tenant.example.com/" },
+			"audience must not be empty",
+		},
+	} {
+		t.Run(tc.scenario, func(t *testing.T) {
+			a := base()
+			tc.mutate(a)
+
+			err := a.Validate()
+
+			if tc.wantErr == "" {
+				if err != nil {
+					t.Fatalf("expected no error, got %v", err)
+				}
+				return
+			}
+			if err == nil || !strings.Contains(err.Error(), tc.wantErr) {
+				t.Fatalf("error = %v, want a substring %q", err, tc.wantErr)
+			}
+		})
+	}
+}