[FEAT] Serve Assets from Docker FileSystem

Dockerfile

@@ -47,4 +47,13 @@ LABEL description="Service status monitor for Rotational applications and system
 # Copy the uptime binary
 COPY --from=builder /go/bin/uptime /usr/local/bin/uptime
 
+# Copy the static assets
+COPY --from=builder /go/src/go.rtnl.ai/uptime/pkg/web/static /var/www/html
+
+ENV UPTIME_STATIC_SERVE=true
+ENV UPTIME_STATIC_ROOT=/var/www/html
+ENV UPTIME_STATIC_URL=/static
+
+EXPOSE 8000
+
 CMD [ "/usr/local/bin/uptime", "serve" ]

pkg/config/config.go

@@ -1,6 +1,10 @@
 package config
 
 import (
+	"errors"
+	"net/url"
+	"os"
+	"strings"
 	"sync"
 
 	"github.com/gin-gonic/gin"
@@ -22,9 +26,17 @@ type Config struct {
 	ConsoleLog     bool              `default:"false" split_words:"true" desc:"if true the server will log to the console in text format"`
 	BindAddr       string            `default:":8000" split_words:"true" desc:"the ip address and port to bind the server to"`
 	AllowedOrigins []string          `split_words:"true" default:"http://localhost:8000" desc:"a list of allowed origins for CORS"`
+	Static         StaticConfig
 	Telemetry      TelemetryConfig
 }
 
+// StaticConfig contains the configuration for the static file server.
+type StaticConfig struct {
+	Serve bool   `default:"true" desc:"if true the static file server will be enabled"`
+	Root  string `default:"pkg/web/static" desc:"the root directory of the static file server"`
+	URL   string `default:"/static" desc:"the URL that static files are served from, either a relative URL or a URL to a CDN"`
+}
+
 // Telemetry is primarily configured via the open telemetry sdk environment variables.
 // As such there is no need to specify OTel specific configuration here. This config
 // is used primarily to enable/disable telemetry and to set values for custom telemetry.
@@ -56,9 +68,46 @@ func New() (conf *Config, err error) {
 
 func (c Config) Validate() (err error) {
 	if c.Mode != gin.ReleaseMode && c.Mode != gin.DebugMode && c.Mode != gin.TestMode {
-		return confire.Invalid("", "mode", "gin mode must be one of: release, debug, test")
+		err = confire.Join(err, confire.Invalid("", "mode", "gin mode must be one of: release, debug, test"))
 	}
-	return nil
+	return err
+}
+
+func (c StaticConfig) Validate() (err error) {
+	if c.Serve {
+		if c.Root == "" {
+			err = confire.Join(err, confire.Required("static", "root"))
+		} else {
+			if _, serr := os.Stat(c.Root); errors.Is(serr, os.ErrNotExist) {
+				err = confire.Join(err, confire.Invalid("static", "root", "directory does not exist"))
+			}
+		}
+	}
+
+	if c.URL == "" {
+		err = confire.Join(err, confire.Required("static", "url"))
+	} else {
+		if strings.Contains(c.URL, "://") {
+			if u, perr := url.Parse(c.URL); perr != nil || u.Scheme == "" || u.Host == "" || u.Path == "" {
+				err = confire.Join(err, confire.Invalid("static", "url", "must be a valid URL with scheme and host"))
+			}
+
+			if c.Serve {
+				err = confire.Join(err, confire.Invalid("static", "url", "cannot use a remote URL if static files are served from the filesystem"))
+			}
+
+		} else {
+			if !strings.HasPrefix(c.URL, "/") {
+				err = confire.Join(err, confire.Invalid("static", "url", "must be a valid URL or an absolute path starting with a slash"))
+			}
+
+			if !c.Serve {
+				err = confire.Join(err, confire.Invalid("static", "url", "must be a remote url if static files are not served from the filesystem"))
+			}
+		}
+	}
+
+	return err
 }
 
 //============================================================================

pkg/config/config_test.go

@@ -17,6 +17,9 @@ var testEnv = contest.Env{
 	"UPTIME_CONSOLE_LOG":       "true",
 	"UPTIME_BIND_ADDR":         ":8888",
 	"UPTIME_ALLOWED_ORIGINS":   "http://localhost:8888",
+	"UPTIME_STATIC_SERVE":      "true",
+	"UPTIME_STATIC_ROOT":       "/tmp",
+	"UPTIME_STATIC_URL":        "/assets",
 	"UPTIME_TELEMETRY_ENABLED": "false",
 	"OTEL_SERVICE_NAME":        "uptime",
 	"GIMLET_OTEL_SERVICE_ADDR": "localhost:8888",
@@ -29,6 +32,11 @@ var validConfig = config.Config{
 	ConsoleLog:     true,
 	BindAddr:       ":8888",
 	AllowedOrigins: []string{"http://localhost:8888"},
+	Static: config.StaticConfig{
+		Serve: true,
+		Root:  "/tmp",
+		URL:   "/assets",
+	},
 	Telemetry: config.TelemetryConfig{
 		Enabled:     false,
 		ServiceName: "uptime",
@@ -67,3 +75,85 @@ func TestConfig(t *testing.T) {
 
 	})
 }
+
+func TestStaticConfigValidate(t *testing.T) {
+
+	t.Run("Valid", func(t *testing.T) {
+		require.NoError(t, validConfig.Static.Validate(), "valid static config should pass validation")
+	})
+
+	t.Run("Invalid", func(t *testing.T) {
+		tests := []struct {
+			name string
+			conf config.StaticConfig
+			err  string
+		}{
+			{
+				"root is required",
+				config.StaticConfig{
+					Serve: true,
+					URL:   "/static",
+				},
+				"invalid configuration: static.root is required but not set",
+			},
+			{
+				"root does not exist",
+				config.StaticConfig{
+					Serve: true,
+					Root:  "/var/lib/www/not-a-directory",
+					URL:   "/static",
+				},
+				"invalid configuration: static.root directory does not exist",
+			},
+			{
+				"url is required",
+				config.StaticConfig{
+					Serve: true,
+					Root:  "../web/static",
+				},
+				"invalid configuration: static.url is required but not set",
+			},
+			{
+				"url is not a valid URL",
+				config.StaticConfig{
+					Serve: false,
+					Root:  "../web/static",
+					URL:   "://not-a-url",
+				},
+				"invalid configuration: static.url must be a valid URL with scheme and host",
+			},
+			{
+				"url is not an absolute path starting with a slash",
+				config.StaticConfig{
+					Serve: true,
+					Root:  "../web/static",
+					URL:   "not-a-slash",
+				},
+				"invalid configuration: static.url must be a valid URL or an absolute path starting with a slash",
+			},
+			{
+				"url is a remote URL and serve is true",
+				config.StaticConfig{
+					Serve: true,
+					Root:  "../web/static",
+					URL:   "https://example.com/static",
+				},
+				"invalid configuration: static.url cannot use a remote URL if static files are served from the filesystem",
+			},
+			{
+				"url is a absolute URL and serve is false",
+				config.StaticConfig{
+					Serve: false,
+					Root:  "../web/static",
+					URL:   "/static",
+				},
+				"invalid configuration: static.url must be a remote url if static files are not served from the filesystem",
+			},
+		}
+
+		for _, test := range tests {
+			err := test.conf.Validate()
+			require.EqualError(t, err, test.err, "expected static config validation error on test case %q", test.name)
+		}
+	})
+}

pkg/server/routes.go

@@ -1,6 +1,10 @@
 package server
 
 import (
+	"net/http"
+	"os"
+	"path/filepath"
+
 	"github.com/gin-gonic/gin"
 	"go.rtnl.ai/gimlet/logger"
 	"go.rtnl.ai/uptime/pkg"
@@ -58,8 +62,11 @@ func (s *Server) setupRoutes() (err error) {
 	s.router.GET("/error", s.InternalError)
 
 	// Static Assets
-	s.router.StaticFS("/static", web.Static())
-	// TODO: add routes for favicon.ico, robots.txt, etc. when they are served from the fs
+	if s.conf.Static.Serve {
+		s.router.StaticFS(s.conf.Static.URL, http.FS(os.DirFS(s.conf.Static.Root)))
+		s.router.StaticFile("/favicon.ico", filepath.Join(s.conf.Static.Root, "favicon.ico"))
+		s.router.StaticFile("/robots.txt", filepath.Join(s.conf.Static.Root, "robots.txt"))
+	}
 
 	// Unauthenticated API Routes
 	v1o := s.router.Group("/v1")

pkg/web/web.go

@@ -7,18 +7,18 @@ import (
 	"html/template"
 	"io/fs"
 	"log/slog"
-	"net/http"
+	"net/url"
 	"path/filepath"
 	"strings"
 	"time"
 
 	"github.com/gin-gonic/gin/render"
+	"go.rtnl.ai/uptime/pkg/config"
 	"go.rtnl.ai/x/rlog"
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 )
 
-//go:embed all:static
 //go:embed all:templates
 var content embed.FS
 
@@ -35,15 +35,6 @@ var (
 	partials = []string{"partials/*.html", "partials/*/*.html"}
 )
 
-// Static creates the StaticFS that contains our static assets to be served.
-func Static() http.FileSystem {
-	staticFiles, err := fs.Sub(content, "static")
-	if err != nil {
-		panic(fmt.Errorf("failed to create static file system: %w", err))
-	}
-	return http.FS(staticFiles)
-}
-
 // Templates returns the FileSystem that contains our HTML templates to be rendered.
 func Templates() fs.FS {
 	templatesFiles, err := fs.Sub(content, "templates")
@@ -130,7 +121,7 @@ func (r *Render) AddPattern(fsys fs.FS, pattern string, includes ...string) (err
 func (r *Render) FuncMap() template.FuncMap {
 	if r.funcs == nil {
 		r.funcs = template.FuncMap{
-			"static":      static,
+			"static":      static(),
 			"titlecase":   titlecase,
 			"lowercase":   lowercase,
 			"uppercase":   uppercase,
@@ -161,14 +152,29 @@ func datetime(t time.Time) string {
 	return t.Format("January 2, 2006 3:04 PM")
 }
 
-func static(path string) string {
-	return filepath.Join("/static", path)
-}
-
 func currentYear() int {
 	return time.Now().Year()
 }
 
+func static() func(path string) string {
+	// Load the configuration to get the static URL.
+	conf := config.MustGet()
+
+	if !conf.Static.Serve {
+		// Treat the bae URL as a remote URL and use URL resolution
+		baseURL, _ := url.Parse(conf.Static.URL)
+		return func(path string) string {
+			return baseURL.ResolveReference(&url.URL{Path: path}).String()
+		}
+	}
+
+	// Otherwise treat the URL as a prefix and returna prepended path.
+	baseURL := conf.Static.URL
+	return func(path string) string {
+		return filepath.Join(baseURL, path)
+	}
+}
+
 // ===========================================================================
 // Helper Functions
 // ===========================================================================

pkg/web/web_test.go

@@ -5,16 +5,67 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/require"
+	"go.rtnl.ai/confire/contest"
+	"go.rtnl.ai/uptime/pkg/config"
 	"go.rtnl.ai/uptime/pkg/web"
 )
 
+var env = contest.Env{
+	"UPTIME_STATIC_SERVE": "true",
+	"UPTIME_STATIC_ROOT":  "./static",
+}
+
 func TestRender(t *testing.T) {
+	t.Cleanup(env.Set())
+	t.Cleanup(config.Reset)
+
 	renderer, err := web.NewRender(web.Templates())
 	require.NoError(t, err)
 	require.NotNil(t, renderer)
 }
 
+func TestStaticServe(t *testing.T) {
+	staticEnv := contest.Env{
+		"UPTIME_STATIC_SERVE": "true",
+		"UPTIME_STATIC_ROOT":  "./static",
+	}
+	t.Cleanup(staticEnv.Set())
+	t.Cleanup(config.Reset)
+
+	render := &web.Render{}
+	funcMap := render.FuncMap()
+	f := funcMap["static"].(func(string) string)
+	require.Equal(t, "/static/favicon.ico", f("favicon.ico"))
+	require.Equal(t, "/static/robots.txt", f("robots.txt"))
+	require.Equal(t, "/static/css/style.css", f("css/style.css"))
+	require.Equal(t, "/static/js/script.js", f("js/script.js"))
+	require.Equal(t, "/static/images/logo.png", f("images/logo.png"))
+	require.Equal(t, "/static/fonts/font.woff", f("fonts/font.woff"))
+}
+
+func TestStaticCDN(t *testing.T) {
+	cdnEnv := contest.Env{
+		"UPTIME_STATIC_SERVE": "false",
+		"UPTIME_STATIC_URL":   "https://cdn.example.com/",
+	}
+	t.Cleanup(cdnEnv.Set())
+	t.Cleanup(config.Reset)
+
+	render := &web.Render{}
+	funcMap := render.FuncMap()
+	f := funcMap["static"].(func(string) string)
+	require.Equal(t, "https://cdn.example.com/favicon.ico", f("favicon.ico"))
+	require.Equal(t, "https://cdn.example.com/robots.txt", f("robots.txt"))
+	require.Equal(t, "https://cdn.example.com/css/style.css", f("css/style.css"))
+	require.Equal(t, "https://cdn.example.com/js/script.js", f("js/script.js"))
+	require.Equal(t, "https://cdn.example.com/images/logo.png", f("images/logo.png"))
+	require.Equal(t, "https://cdn.example.com/fonts/font.woff", f("fonts/font.woff"))
+}
+
 func TestFuncMap(t *testing.T) {
+	t.Cleanup(env.Set())
+	t.Cleanup(config.Reset)
+
 	renderer := &web.Render{}
 	funcMap := renderer.FuncMap()
 
@@ -83,6 +134,11 @@ func TestFuncMap(t *testing.T) {
 		}
 	})
 
+	t.Run("currentYear", func(t *testing.T) {
+		f := funcMap["currentYear"].(func() int)
+		require.Equal(t, time.Now().Year(), f())
+	})
+
 	t.Run("static", func(t *testing.T) {
 		testCases := []struct {
 			input    string