coder · dannykopping · Apr 15, 2025 · Apr 11, 2025 · Apr 11, 2025 · Apr 11, 2025
diff --git a/coderd/coderd.go b/coderd/coderd.go
@@ -675,10 +675,11 @@ func New(options *Options) *API {
 	api.Auditor.Store(&options.Auditor)
 	api.TailnetCoordinator.Store(&options.TailnetCoordinator)
 	dialer := &InmemTailnetDialer{
-		CoordPtr: &api.TailnetCoordinator,
-		DERPFn:   api.DERPMap,
-		Logger:   options.Logger,
-		ClientID: uuid.New(),
+		CoordPtr:            &api.TailnetCoordinator,
+		DERPFn:              api.DERPMap,
+		Logger:              options.Logger,
+		ClientID:            uuid.New(),
+		DatabaseHealthCheck: api.Database,
 	}
 	stn, err := NewServerTailnet(api.ctx,
 		options.Logger,

diff --git a/coderd/tailnet.go b/coderd/tailnet.go
@@ -24,9 +24,11 @@ import (
 	"tailscale.com/tailcfg"
 
 	"cdr.dev/slog"
+
 	"github.com/coder/coder/v2/coderd/tracing"
 	"github.com/coder/coder/v2/coderd/workspaceapps"
 	"github.com/coder/coder/v2/coderd/workspaceapps/appurl"
+	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/workspacesdk"
 	"github.com/coder/coder/v2/site"
 	"github.com/coder/coder/v2/tailnet"
@@ -534,16 +536,28 @@ func NewMultiAgentController(ctx context.Context, logger slog.Logger, tracer tra
 	return m
 }
 
+type Pinger interface {
+	Ping(context.Context) (time.Duration, error)
+}
+
 // InmemTailnetDialer is a tailnet.ControlProtocolDialer that connects to a Coordinator and DERPMap
 // service running in the same memory space.
 type InmemTailnetDialer struct {
 	CoordPtr *atomic.Pointer[tailnet.Coordinator]
 	DERPFn   func() *tailcfg.DERPMap
 	Logger   slog.Logger
 	ClientID uuid.UUID
+	// DatabaseHealthCheck is used to validate that the store is reachable.
+	DatabaseHealthCheck Pinger
 }
 
-func (a *InmemTailnetDialer) Dial(_ context.Context, _ tailnet.ResumeTokenController) (tailnet.ControlProtocolClients, error) {
+func (a *InmemTailnetDialer) Dial(ctx context.Context, _ tailnet.ResumeTokenController) (tailnet.ControlProtocolClients, error) {
+	if a.DatabaseHealthCheck != nil {
+		if _, err := a.DatabaseHealthCheck.Ping(ctx); err != nil {
+			return tailnet.ControlProtocolClients{}, xerrors.Errorf("%w: %v", codersdk.ErrDatabaseNotReachable, err)
+		}
+	}
+
 	coord := a.CoordPtr.Load()
 	if coord == nil {
 		return tailnet.ControlProtocolClients{}, xerrors.Errorf("tailnet coordinator not initialized")

diff --git a/coderd/tailnet_test.go b/coderd/tailnet_test.go
@@ -11,20 +11,23 @@ import (
 	"strconv"
 	"sync/atomic"
 	"testing"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/otel/trace"
+	"golang.org/x/xerrors"
 	"tailscale.com/tailcfg"
 
 	"github.com/coder/coder/v2/agent"
 	"github.com/coder/coder/v2/agent/agenttest"
 	"github.com/coder/coder/v2/agent/proto"
 	"github.com/coder/coder/v2/coderd"
 	"github.com/coder/coder/v2/coderd/workspaceapps/appurl"
+	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/agentsdk"
 	"github.com/coder/coder/v2/codersdk/workspacesdk"
 	"github.com/coder/coder/v2/tailnet"
@@ -365,6 +368,44 @@ func TestServerTailnet_ReverseProxy(t *testing.T) {
 	})
 }
 
+func TestDialFailure(t *testing.T) {
+	t.Parallel()
+
+	// Setup.
+	ctx := testutil.Context(t, testutil.WaitShort)
+	logger := testutil.Logger(t)
+
+	// Given: a tailnet coordinator.
+	coord := tailnet.NewCoordinator(logger)
+	t.Cleanup(func() {
+		_ = coord.Close()
+	})
+	coordPtr := atomic.Pointer[tailnet.Coordinator]{}
+	coordPtr.Store(&coord)
+
+	// Given: a fake DB healthchecker which will always fail.
+	fch := &failingHealthcheck{}
+
+	// When: dialing the in-memory coordinator.
+	dialer := &coderd.InmemTailnetDialer{
+		CoordPtr:            &coordPtr,
+		Logger:              logger,
+		ClientID:            uuid.UUID{5},
+		DatabaseHealthCheck: fch,
+	}
+	_, err := dialer.Dial(ctx, nil)
+
+	// Then: the error returned reflects the database has failed its healthcheck.
+	require.ErrorIs(t, err, codersdk.ErrDatabaseNotReachable)
+}
+
+type failingHealthcheck struct{}
+
+func (failingHealthcheck) Ping(context.Context) (time.Duration, error) {
+	// Simulate a database connection error.
+	return 0, xerrors.New("oops")
+}
+
 type wrappedListener struct {
 	net.Listener
 	dials int32

diff --git a/coderd/workspaceagents.go b/coderd/workspaceagents.go
@@ -997,6 +997,16 @@ func (api *API) derpMapUpdates(rw http.ResponseWriter, r *http.Request) {
 func (api *API) workspaceAgentClientCoordinate(rw http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 
+	// Ensure the database is reachable before proceeding.
+	_, err := api.Database.Ping(ctx)
+	if err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: codersdk.DatabaseNotReachable,
+			Detail:  err.Error(),
+		})
+		return
+	}
+
 	// This route accepts user API key auth and workspace proxy auth. The moon actor has
 	// full permissions so should be able to pass this authz check.
 	workspace := httpmw.WorkspaceParam(r)

diff --git a/codersdk/database.go b/codersdk/database.go
@@ -0,0 +1,7 @@
+package codersdk
+
+import "golang.org/x/xerrors"
+
+const DatabaseNotReachable = "database not reachable"
+
+var ErrDatabaseNotReachable = xerrors.New(DatabaseNotReachable)
diff --git a/codersdk/workspacesdk/dialer.go b/codersdk/workspacesdk/dialer.go
@@ -11,17 +11,19 @@ import (
 	"golang.org/x/xerrors"
 
 	"cdr.dev/slog"
+	"github.com/coder/websocket"
+
 	"github.com/coder/coder/v2/buildinfo"
 	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/tailnet"
 	"github.com/coder/coder/v2/tailnet/proto"
-	"github.com/coder/websocket"
 )
 
 var permanentErrorStatuses = []int{
-	http.StatusConflict,   // returned if client/agent connections disabled (browser only)
-	http.StatusBadRequest, // returned if API mismatch
-	http.StatusNotFound,   // returned if user doesn't have permission or agent doesn't exist
+	http.StatusConflict,            // returned if client/agent connections disabled (browser only)
+	http.StatusBadRequest,          // returned if API mismatch
+	http.StatusNotFound,            // returned if user doesn't have permission or agent doesn't exist
+	http.StatusInternalServerError, // returned if database is not reachable,
 }
 
 type WebsocketDialer struct {
@@ -89,6 +91,11 @@ func (w *WebsocketDialer) Dial(ctx context.Context, r tailnet.ResumeTokenControl
 						"Ensure your client release version (%s, different than the API version) matches the server release version",
 						buildinfo.Version())
 				}
+
+				if sdkErr.Message == codersdk.DatabaseNotReachable &&
+					sdkErr.StatusCode() == http.StatusInternalServerError {
+					err = xerrors.Errorf("%w: %v", codersdk.ErrDatabaseNotReachable, err)
+				}
 			}
 			w.connected <- err
 			return tailnet.ControlProtocolClients{}, err

diff --git a/codersdk/workspacesdk/workspacesdk_test.go b/codersdk/workspacesdk/workspacesdk_test.go
@@ -1,13 +1,21 @@
 package workspacesdk_test
 
 import (
+	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 	"tailscale.com/tailcfg"
 
+	"github.com/coder/websocket"
+
+	"github.com/coder/coder/v2/coderd/httpapi"
+	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/agentsdk"
+	"github.com/coder/coder/v2/codersdk/workspacesdk"
+	"github.com/coder/coder/v2/testutil"
 )
 
 func TestWorkspaceRewriteDERPMap(t *testing.T) {
@@ -37,3 +45,30 @@ func TestWorkspaceRewriteDERPMap(t *testing.T) {
 	require.Equal(t, "coconuts.org", node.HostName)
 	require.Equal(t, 44558, node.DERPPort)
 }
+
+func TestWorkspaceDialerFailure(t *testing.T) {
+	t.Parallel()
+
+	// Setup.
+	ctx := testutil.Context(t, testutil.WaitShort)
+	logger := testutil.Logger(t)
+
+	// Given: a mock HTTP server which mimicks an unreachable database when calling the coordination endpoint.
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		httpapi.Write(ctx, w, http.StatusInternalServerError, codersdk.Response{
+			Message: codersdk.DatabaseNotReachable,
+			Detail:  "oops",
+		})
+	}))
+	t.Cleanup(srv.Close)
+
+	u, err := url.Parse(srv.URL)
+	require.NoError(t, err)
+
+	// When: calling the coordination endpoint.
+	dialer := workspacesdk.NewWebsocketDialer(logger, u, &websocket.DialOptions{})
+	_, err = dialer.Dial(ctx, nil)
+
+	// Then: an error indicating a database issue is returned, to conditionalize the behavior of the caller.
+	require.ErrorIs(t, err, codersdk.ErrDatabaseNotReachable)
+}
diff --git a/provisionerd/provisionerd.go b/provisionerd/provisionerd.go
@@ -20,12 +20,13 @@ import (
 	"golang.org/x/xerrors"
 
 	"cdr.dev/slog"
+	"github.com/coder/retry"
+
 	"github.com/coder/coder/v2/coderd/tracing"
 	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/provisionerd/proto"
 	"github.com/coder/coder/v2/provisionerd/runner"
 	sdkproto "github.com/coder/coder/v2/provisionersdk/proto"
-	"github.com/coder/retry"
 )
 
 // Dialer represents the function to create a daemon client connection.
@@ -290,7 +291,7 @@ func (p *Server) acquireLoop() {
 	defer p.wg.Done()
 	defer func() { close(p.acquireDoneCh) }()
 	ctx := p.closeContext
-	for {
+	for retrier := retry.New(10*time.Millisecond, 1*time.Second); retrier.Wait(ctx); {
 		if p.acquireExit() {
 			return
 		}
@@ -299,7 +300,17 @@ func (p *Server) acquireLoop() {
 			p.opts.Logger.Debug(ctx, "shut down before client (re) connected")
 			return
 		}
-		p.acquireAndRunOne(client)
+		err := p.acquireAndRunOne(client)
+		if err != nil && ctx.Err() == nil { // Only log if context is not done.
+			// Short-circuit: don't wait for the retry delay to exit, if required.
+			if p.acquireExit() {
+				return
+			}
+			p.opts.Logger.Warn(ctx, "failed to acquire job, retrying", slog.F("delay", fmt.Sprintf("%vms", retrier.Delay.Milliseconds())), slog.Error(err))
+		} else {
+			// Reset the retrier after each successful acquisition.
+			retrier.Reset()
+		}
 	}
 }
 
@@ -318,7 +329,7 @@ func (p *Server) acquireExit() bool {
 	return false
 }
 
-func (p *Server) acquireAndRunOne(client proto.DRPCProvisionerDaemonClient) {
+func (p *Server) acquireAndRunOne(client proto.DRPCProvisionerDaemonClient) error {
 	ctx := p.closeContext
 	p.opts.Logger.Debug(ctx, "start of acquireAndRunOne")
 	job, err := p.acquireGraceful(client)
@@ -327,15 +338,15 @@ func (p *Server) acquireAndRunOne(client proto.DRPCProvisionerDaemonClient) {
 		if errors.Is(err, context.Canceled) ||
 			errors.Is(err, yamux.ErrSessionShutdown) ||
 			errors.Is(err, fasthttputil.ErrInmemoryListenerClosed) {
-			return
+			return err
 		}
 
 		p.opts.Logger.Warn(ctx, "provisionerd was unable to acquire job", slog.Error(err))
-		return
+		return xerrors.Errorf("failed to acquire job: %w", err)
 	}
 	if job.JobId == "" {
 		p.opts.Logger.Debug(ctx, "acquire job successfully canceled")
-		return
+		return nil
 	}
 
 	if len(job.TraceMetadata) > 0 {
@@ -390,9 +401,9 @@ func (p *Server) acquireAndRunOne(client proto.DRPCProvisionerDaemonClient) {
 			Error: fmt.Sprintf("failed to connect to provisioner: %s", resp.Error),
 		})
 		if err != nil {
-			p.opts.Logger.Error(ctx, "provisioner job failed", slog.F("job_id", job.JobId), slog.Error(err))
+			p.opts.Logger.Error(ctx, "failed to report provisioner job failed", slog.F("job_id", job.JobId), slog.Error(err))
 		}
-		return
+		return xerrors.Errorf("failed to report provisioner job failed: %w", err)
 	}
 
 	p.mutex.Lock()
@@ -416,6 +427,7 @@ func (p *Server) acquireAndRunOne(client proto.DRPCProvisionerDaemonClient) {
 	p.mutex.Lock()
 	p.activeJob = nil
 	p.mutex.Unlock()
+	return nil
 }
 
 // acquireGraceful attempts to acquire a job from the server, handling canceling the acquisition if we gracefully shut

diff --git a/site/src/api/typesGenerated.ts b/site/src/api/typesGenerated.ts
diff --git a/tailnet/controllers.go b/tailnet/controllers.go
@@ -2,6 +2,7 @@ package tailnet
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"maps"
@@ -21,11 +22,12 @@ import (
 	"tailscale.com/util/dnsname"
 
 	"cdr.dev/slog"
+	"github.com/coder/quartz"
+	"github.com/coder/retry"
+
 	"github.com/coder/coder/v2/coderd/util/ptr"
 	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/tailnet/proto"
-	"github.com/coder/quartz"
-	"github.com/coder/retry"
 )
 
 // A Controller connects to the tailnet control plane, and then uses the control protocols to
@@ -1381,6 +1383,14 @@ func (c *Controller) Run(ctx context.Context) {
 				if xerrors.Is(err, context.Canceled) || xerrors.Is(err, context.DeadlineExceeded) {
 					return
 				}
+
+				// If the database is unreachable by the control plane, there's not much we can do, so we'll just retry later.
+				if errors.Is(err, codersdk.ErrDatabaseNotReachable) {
+					c.logger.Warn(c.ctx, "control plane lost connection to database, retrying",
+						slog.Error(err), slog.F("delay", fmt.Sprintf("%vms", retrier.Delay.Milliseconds())))
+					continue
+				}
+
 				errF := slog.Error(err)
 				var sdkErr *codersdk.Error
 				if xerrors.As(err, &sdkErr) {