fix(coderd): exclude sub-agents from workspace health calculation

mafredri · mafredri · commit 3e94111ae4c8 · 2025-12-04T12:13:15.000Z
Previously, when a devcontainer was rebuilding, its sub-agent would
become temporarily disconnected, causing the workspace to show as
unhealthy. This was confusing because the workspace itself was fine.

Sub-agents (agents with a ParentID) are now excluded from the workspace
health calculation. Their health is managed by their parent agent, and
temporary disconnections during devcontainer rebuilds should not affect
the overall workspace health status.
diff --git a/coderd/workspaces.go b/coderd/workspaces.go
@@ -2598,6 +2598,13 @@ func convertWorkspace(
 	failingAgents := []uuid.UUID{}
 	for _, resource := range workspaceBuild.Resources {
 		for _, agent := range resource.Agents {
+			// Sub-agents (e.g., devcontainer agents) are excluded from the
+			// workspace health calculation. Their health is managed by
+			// their parent agent, and temporary disconnections during
+			// devcontainer rebuilds should not affect workspace health.
+			if agent.ParentID.Valid {
+				continue
+			}
 			if !agent.Health.Healthy {
 				failingAgents = append(failingAgents, agent.ID)
 			}
diff --git a/coderd/workspaces_test.go b/coderd/workspaces_test.go
@@ -346,6 +346,82 @@ func TestWorkspace(t *testing.T) {
 			assert.False(t, agent2.Health.Healthy)
 			assert.NotEmpty(t, agent2.Health.Reason)
 		})
+
+		t.Run("Sub-agent excluded", func(t *testing.T) {
+			t.Parallel()
+			// This test verifies that sub-agents (e.g., devcontainer agents)
+			// are excluded from the workspace health calculation. When a
+			// devcontainer is rebuilding, the sub-agent may be temporarily
+			// disconnected, but this should not make the workspace unhealthy.
+			client, db := coderdtest.NewWithDatabase(t, &coderdtest.Options{IncludeProvisionerDaemon: true})
+			user := coderdtest.CreateFirstUser(t, client)
+			version := coderdtest.CreateTemplateVersion(t, client, user.OrganizationID, &echo.Responses{
+				Parse: echo.ParseComplete,
+				ProvisionApply: []*proto.Response{{
+					Type: &proto.Response_Apply{
+						Apply: &proto.ApplyComplete{
+							Resources: []*proto.Resource{{
+								Name: "some",
+								Type: "example",
+								Agents: []*proto.Agent{{
+									Id:   uuid.NewString(),
+									Name: "parent",
+									Auth: &proto.Agent_Token{},
+								}},
+							}},
+						},
+					},
+				}},
+			})
+			coderdtest.AwaitTemplateVersionJobCompleted(t, client, version.ID)
+			template := coderdtest.CreateTemplate(t, client, user.OrganizationID, version.ID)
+			workspace := coderdtest.CreateWorkspace(t, client, template.ID)
+			coderdtest.AwaitWorkspaceBuildJobCompleted(t, client, workspace.LatestBuild.ID)
+
+			ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitLong)
+			defer cancel()
+
+			// Get the workspace and parent agent.
+			workspace, err := client.Workspace(ctx, workspace.ID)
+			require.NoError(t, err)
+			parentAgent := workspace.LatestBuild.Resources[0].Agents[0]
+			require.True(t, parentAgent.Health.Healthy, "parent agent should be healthy initially")
+
+			// Create a sub-agent with a short connection timeout so it becomes
+			// unhealthy quickly (simulating a devcontainer rebuild scenario).
+			//nolint:gocritic // This is a test, we need to insert a sub-agent directly.
+			subAgent := dbgen.WorkspaceAgent(t, db, database.WorkspaceAgent{
+				ParentID:                 uuid.NullUUID{Valid: true, UUID: parentAgent.ID},
+				ResourceID:               parentAgent.ResourceID,
+				Name:                     "subagent",
+				ConnectionTimeoutSeconds: 1,
+			})
+
+			// Wait for the sub-agent to become unhealthy due to timeout.
+			var subAgentUnhealthy bool
+			require.Eventually(t, func() bool {
+				workspace, err = client.Workspace(ctx, workspace.ID)
+				if err != nil {
+					return false
+				}
+				for _, res := range workspace.LatestBuild.Resources {
+					for _, agent := range res.Agents {
+						if agent.ID == subAgent.ID && !agent.Health.Healthy {
+							subAgentUnhealthy = true
+							return true
+						}
+					}
+				}
+				return false
+			}, testutil.WaitShort, testutil.IntervalFast, "sub-agent should become unhealthy")
+
+			require.True(t, subAgentUnhealthy, "sub-agent should be unhealthy")
+
+			// Verify that the workspace is still healthy because sub-agents
+			// are excluded from the health calculation.
+			assert.True(t, workspace.Health.Healthy, "workspace should be healthy despite unhealthy sub-agent")
+			assert.Empty(t, workspace.Health.FailingAgents, "failing agents should not include sub-agent")
+		})
 	})
 
 	t.Run("Archived", func(t *testing.T) {
