feat: Implement start of external workspace proxies

coder · deansheather · Apr 17, 2023 · Apr 5, 2023 · Apr 5, 2023 · Apr 6, 2023
commit ca5b50c785000d24f5397a5f48711d8b78c20195
diff --git a/enterprise/externalproxy/proxy.go b/enterprise/externalproxy/proxy.go
@@ -0,0 +1,161 @@
+package externalproxy
+
+import (
+	"net/http"
+	"net/url"
+	"regexp"
+	"time"
+
+	"github.com/coder/coder/buildinfo"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/coder/coder/coderd/tracing"
+	"go.opentelemetry.io/otel/trace"
+
+	"github.com/go-chi/chi/v5"
+
+	"github.com/coder/coder/coderd/wsconncache"
+
+	"github.com/coder/coder/coderd/httpmw"
+
+	"cdr.dev/slog"
+	"github.com/coder/coder/coderd/workspaceapps"
+)
+
+type Options struct {
+	Logger slog.Logger
+
+	// PrimaryAccessURL is the URL of the primary coderd instance.
+	// This also serves as the DashboardURL.
+	PrimaryAccessURL *url.URL
+	// AccessURL is the URL of the WorkspaceProxy. This is the url to communicate
+	// with this server.
+	AccessURL *url.URL
+
+	// TODO: @emyrk We use these two fields in many places with this comment.
+	//		Maybe we should make some shared options struct?
+	// AppHostname should be the wildcard hostname to use for workspace
+	// applications INCLUDING the asterisk, (optional) suffix and leading dot.
+	// It will use the same scheme and port number as the access URL.
+	// E.g. "*.apps.coder.com" or "*-apps.coder.com".
+	AppHostname string
+	// AppHostnameRegex contains the regex version of options.AppHostname as
+	// generated by httpapi.CompileHostnamePattern(). It MUST be set if
+	// options.AppHostname is set.
+	AppHostnameRegex *regexp.Regexp
+
+	RealIPConfig *httpmw.RealIPConfig
+	// TODO: @emyrk this key needs to be provided via a file or something?
+	//		Maybe we should curl it from the primary over some secure connection?
+	AppSecurityKey workspaceapps.SecurityKey
+
+	Tracing            trace.TracerProvider
+	PrometheusRegistry *prometheus.Registry
+
+	APIRateLimit     int
+	SecureAuthCookie bool
+}
+
+// Server is an external workspace proxy server. This server can communicate
+// directly with a workspace. It requires a primary coderd to establish a said
+// connection.
+type Server struct {
+	PrimaryAccessURL *url.URL
+	AppServer        *workspaceapps.Server
+
+	// Logging/Metrics
+	Logger             slog.Logger
+	TracerProvider     trace.TracerProvider
+	PrometheusRegistry *prometheus.Registry
+
+	Handler chi.Router
+
+	// TODO: Missing:
+	//		- derpserver
+
+	Options *Options
+}
+
+func New(opts *Options) *Server {
+	if opts.PrometheusRegistry == nil {
+		opts.PrometheusRegistry = prometheus.NewRegistry()
+	}
+
+	r := chi.NewRouter()
+	s := &Server{
+		Options:          opts,
+		PrimaryAccessURL: opts.PrimaryAccessURL,
+		AppServer: &workspaceapps.Server{
+			Logger:        opts.Logger.Named("workspaceapps"),
+			DashboardURL:  opts.PrimaryAccessURL,
+			AccessURL:     opts.AccessURL,
+			Hostname:      opts.AppHostname,
+			HostnameRegex: opts.AppHostnameRegex,
+			// TODO: @emyrk We should reduce the options passed in here.
+			DeploymentValues: nil,
+			RealIPConfig:     opts.RealIPConfig,
+			// TODO: @emyrk we need to implement this for external token providers.
+			SignedTokenProvider: nil,
+			// TODO: @emyrk we need to implement a dialer
+			WorkspaceConnCache: wsconncache.New(nil, 0),
+			AppSecurityKey:     opts.AppSecurityKey,
+		},
+		Logger:             opts.Logger.Named("workspace-proxy"),
+		TracerProvider:     opts.Tracing,
+		PrometheusRegistry: opts.PrometheusRegistry,
+		Handler:            r,
+	}
+
+	// Routes
+	apiRateLimiter := httpmw.RateLimit(opts.APIRateLimit, time.Minute)
+	// Persistant middlewares to all routes
+	r.Use(
+		// TODO: @emyrk Should we standardize these in some other package?
+		httpmw.Recover(s.Logger),
+		tracing.StatusWriterMiddleware,
+		tracing.Middleware(s.TracerProvider),
+		httpmw.AttachRequestID,
+		httpmw.ExtractRealIP(s.Options.RealIPConfig),
+		httpmw.Logger(s.Logger),
+		httpmw.Prometheus(s.PrometheusRegistry),
+
+		// SubdomainAppMW is a middleware that handles all requests to the
+		// subdomain based workspace apps.
+		s.AppServer.SubdomainAppMW(apiRateLimiter),
+		// Build-Version is helpful for debugging.
+		func(next http.Handler) http.Handler {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.Header().Add("X-Coder-Build-Version", buildinfo.Version())
+				next.ServeHTTP(w, r)
+			})
+		},
+		// This header stops a browser from trying to MIME-sniff the content type and
+		// forces it to stick with the declared content-type. This is the only valid
+		// value for this header.
+		// See: https://github.com/coder/security/issues/12
+		func(next http.Handler) http.Handler {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.Header().Add("X-Content-Type-Options", "nosniff")
+				next.ServeHTTP(w, r)
+			})
+		},
+		// TODO: @emyrk we might not need this? But good to have if it does
+		// 		not break anything.
+		httpmw.CSRF(s.Options.SecureAuthCookie),
+	)
+
+	// Attach workspace apps routes.
+	r.Group(func(r chi.Router) {
+		r.Use(apiRateLimiter)
+		s.AppServer.Attach(r)
+	})
+
+	// TODO: @emyrk Buildinfo and healthz routes.
+
+	return s
+}
+
+func (s *Server) Close() error {
+	return s.AppServer.Close()
+}