feat: Add support for update checks and notifications (#4810)

Co-authored-by: Kira Pilot <kira@coder.com>

coderd/coderd.go

@@ -47,6 +47,7 @@ import (
 	"github.com/coder/coder/coderd/rbac"
 	"github.com/coder/coder/coderd/telemetry"
 	"github.com/coder/coder/coderd/tracing"
+	"github.com/coder/coder/coderd/updatecheck"
 	"github.com/coder/coder/coderd/wsconncache"
 	"github.com/coder/coder/codersdk"
 	"github.com/coder/coder/provisionerd/proto"
@@ -105,6 +106,7 @@ type Options struct {
 	AgentStatsRefreshInterval   time.Duration
 	Experimental                bool
 	DeploymentConfig            *codersdk.DeploymentConfig
+	UpdateCheckOptions          *updatecheck.Options // Set non-nil to enable update checking.
 }
 
 // New constructs a Coder API handler.
@@ -123,7 +125,7 @@ func New(options *Options) *API {
 		options.AgentInactiveDisconnectTimeout = options.AgentConnectionUpdateFrequency * 2
 	}
 	if options.AgentStatsRefreshInterval == 0 {
-		options.AgentStatsRefreshInterval = 10 * time.Minute
+		options.AgentStatsRefreshInterval = 5 * time.Minute
 	}
 	if options.MetricsCacheRefreshInterval == 0 {
 		options.MetricsCacheRefreshInterval = time.Hour
@@ -131,12 +133,6 @@ func New(options *Options) *API {
 	if options.APIRateLimit == 0 {
 		options.APIRateLimit = 512
 	}
-	if options.AgentStatsRefreshInterval == 0 {
-		options.AgentStatsRefreshInterval = 5 * time.Minute
-	}
-	if options.MetricsCacheRefreshInterval == 0 {
-		options.MetricsCacheRefreshInterval = time.Hour
-	}
 	if options.Authorizer == nil {
 		options.Authorizer = rbac.NewAuthorizer()
 	}
@@ -181,6 +177,13 @@ func New(options *Options) *API {
 		metricsCache: metricsCache,
 		Auditor:      atomic.Pointer[audit.Auditor]{},
 	}
+	if options.UpdateCheckOptions != nil {
+		api.updateChecker = updatecheck.New(
+			options.Database,
+			options.Logger.Named("update_checker"),
+			*options.UpdateCheckOptions,
+		)
+	}
 	api.Auditor.Store(&options.Auditor)
 	api.workspaceAgentCache = wsconncache.New(api.dialWorkspaceAgentTailnet, 0)
 	api.TailnetCoordinator.Store(&options.TailnetCoordinator)
@@ -308,6 +311,9 @@ func New(options *Options) *API {
 				})
 			})
 		})
+		r.Route("/updatecheck", func(r chi.Router) {
+			r.Get("/", api.updateCheck)
+		})
 		r.Route("/config", func(r chi.Router) {
 			r.Use(apiKeyMiddleware)
 			r.Get("/deployment", api.deploymentConfig)
@@ -590,13 +596,14 @@ type API struct {
 	// RootHandler serves "/"
 	RootHandler chi.Router
 
-	metricsCache *metricscache.Cache
-	siteHandler  http.Handler
+	siteHandler http.Handler
 
 	WebsocketWaitMutex sync.Mutex
 	WebsocketWaitGroup sync.WaitGroup
 
+	metricsCache        *metricscache.Cache
 	workspaceAgentCache *wsconncache.Cache
+	updateChecker       *updatecheck.Checker
 }
 
 // Close waits for all WebSocket connections to drain before returning.
@@ -606,6 +613,9 @@ func (api *API) Close() error {
 	api.WebsocketWaitMutex.Unlock()
 
 	api.metricsCache.Close()
+	if api.updateChecker != nil {
+		api.updateChecker.Close()
+	}
 	coordinator := api.TailnetCoordinator.Load()
 	if coordinator != nil {
 		_ = (*coordinator).Close()