feat: add custom health check commands per app

Add configurable health check commands per app via a new
'healthcheck_command' field. When set, the command is passed
to Docker as a CMD-SHELL health check on the container.
When empty, the image's default health check is used.

Changes:
- Add migration 007 for healthcheck_command column on apps table
- Add HealthcheckCommand field to App model with full CRUD support
- Add buildHealthcheck() to docker client for CMD-SHELL config
- Pass health check command through CreateContainerOptions
- Add health check command input to app create/edit UI forms
- Extract optionalNullString helper to reduce handler complexity
- Update README features list

closes #81

README.md

@@ -8,7 +8,7 @@ A simple self-hosted PaaS that auto-deploys Docker containers from Git repositor
 - Per-app SSH keypairs for read-only deploy keys
 - Per-app UUID-based webhook URLs for Gitea integration
 - Branch filtering - only deploy on configured branch changes
-- Environment variables, labels, and volume mounts per app
+- Environment variables, labels, volume mounts, and custom health checks per app
 - Docker builds via socket access
 - Notifications via ntfy and Slack-compatible webhooks
 - Simple server-rendered UI with Tailwind CSS

internal/database/migrations/007_add_healthcheck_command.sql

@@ -0,0 +1,2 @@
+-- Add custom health check command per app
+ALTER TABLE apps ADD COLUMN healthcheck_command TEXT;

internal/docker/client.go

@@ -13,6 +13,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"time"
 
 	dockertypes "github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/container"
@@ -145,6 +146,7 @@ type CreateContainerOptions struct {
 	Volumes            []VolumeMount
 	Ports              []PortMapping
 	Network            string
+	HealthcheckCommand string // Custom health check shell command (empty = use image default)
 }
 
 // VolumeMount represents a volume mount.
@@ -185,6 +187,29 @@ func buildPortConfig(ports []PortMapping) (nat.PortSet, nat.PortMap) {
 	return exposedPorts, portBindings
 }
 
+// healthcheckInterval is the time between health check attempts.
+const healthcheckInterval = 30 * time.Second
+
+// healthcheckTimeout is the maximum time a single health check can take.
+const healthcheckTimeout = 10 * time.Second
+
+// healthcheckStartPeriod is the grace period before health checks start counting failures.
+const healthcheckStartPeriod = 15 * time.Second
+
+// healthcheckRetries is the number of consecutive failures needed to mark unhealthy.
+const healthcheckRetries = 3
+
+// buildHealthcheck creates a Docker health check config from a shell command string.
+func buildHealthcheck(command string) *container.HealthConfig {
+	return &container.HealthConfig{
+		Test:        []string{"CMD-SHELL", command},
+		Interval:    healthcheckInterval,
+		Timeout:     healthcheckTimeout,
+		StartPeriod: healthcheckStartPeriod,
+		Retries:     healthcheckRetries,
+	}
+}
+
 // CreateContainer creates a new container.
 func (c *Client) CreateContainer(
 	ctx context.Context,
@@ -218,14 +243,22 @@ func (c *Client) CreateContainer(
 	// Convert ports to exposed ports and port bindings
 	exposedPorts, portBindings := buildPortConfig(opts.Ports)
 
-	// Create container
-	resp, err := c.docker.ContainerCreate(ctx,
-		&container.Config{
+	// Build container config
+	containerConfig := &container.Config{
 		Image:        opts.Image,
 		Env:          envSlice,
 		Labels:       opts.Labels,
 		ExposedPorts: exposedPorts,
-		},
+	}
+
+	// Apply custom health check if configured
+	if opts.HealthcheckCommand != "" {
+		containerConfig.Healthcheck = buildHealthcheck(opts.HealthcheckCommand)
+	}
+
+	// Create container
+	resp, err := c.docker.ContainerCreate(ctx,
+		containerConfig,
 		&container.HostConfig{
 			Mounts:       mounts,
 			PortBindings: portBindings,

internal/docker/validation_test.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"log/slog"
 	"testing"
+	"time"
 )
 
 func TestValidBranchRegex(t *testing.T) {
@@ -146,3 +147,52 @@ func TestCloneRepoRejectsInjection(t *testing.T) { //nolint:funlen // table-driv
 		})
 	}
 }
+
+func TestBuildHealthcheck(t *testing.T) {
+	t.Parallel()
+
+	t.Run("creates CMD-SHELL health check", func(t *testing.T) {
+		t.Parallel()
+
+		cmd := "curl -f http://localhost:8080/healthz || exit 1"
+		hc := buildHealthcheck(cmd)
+
+		if len(hc.Test) != 2 {
+			t.Fatalf("expected 2 test elements, got %d", len(hc.Test))
+		}
+
+		if hc.Test[0] != "CMD-SHELL" {
+			t.Errorf("expected Test[0]=%q, got %q", "CMD-SHELL", hc.Test[0])
+		}
+
+		if hc.Test[1] != cmd {
+			t.Errorf("expected Test[1]=%q, got %q", cmd, hc.Test[1])
+		}
+	})
+
+	t.Run("sets expected intervals", func(t *testing.T) {
+		t.Parallel()
+
+		hc := buildHealthcheck("true")
+
+		expectedInterval := 30 * time.Second
+		if hc.Interval != expectedInterval {
+			t.Errorf("expected Interval=%v, got %v", expectedInterval, hc.Interval)
+		}
+
+		expectedTimeout := 10 * time.Second
+		if hc.Timeout != expectedTimeout {
+			t.Errorf("expected Timeout=%v, got %v", expectedTimeout, hc.Timeout)
+		}
+
+		expectedStartPeriod := 15 * time.Second
+		if hc.StartPeriod != expectedStartPeriod {
+			t.Errorf("expected StartPeriod=%v, got %v", expectedStartPeriod, hc.StartPeriod)
+		}
+
+		expectedRetries := 3
+		if hc.Retries != expectedRetries {
+			t.Errorf("expected Retries=%d, got %d", expectedRetries, hc.Retries)
+		}
+	})
+}

internal/handlers/app.go

@@ -57,6 +57,7 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 		dockerNetwork := request.FormValue("docker_network")
 		ntfyTopic := request.FormValue("ntfy_topic")
 		slackWebhook := request.FormValue("slack_webhook")
+		healthcheckCommand := request.FormValue("healthcheck_command")
 
 		data := h.addGlobals(map[string]any{
 			"Name":               name,
@@ -66,6 +67,7 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 			"DockerNetwork":      dockerNetwork,
 			"NtfyTopic":          ntfyTopic,
 			"SlackWebhook":       slackWebhook,
+			"HealthcheckCommand": healthcheckCommand,
 		}, request)
 
 		if name == "" || repoURL == "" {
@@ -109,6 +111,7 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 				DockerNetwork:      dockerNetwork,
 				NtfyTopic:          ntfyTopic,
 				SlackWebhook:       slackWebhook,
+				HealthcheckCommand: healthcheckCommand,
 			},
 		)
 		if createErr != nil {
@@ -208,6 +211,11 @@ func (h *Handlers) HandleAppEdit() http.HandlerFunc {
 	}
 }
 
+// optionalNullString returns a valid NullString if the value is non-empty, or an empty NullString.
+func optionalNullString(value string) sql.NullString {
+	return sql.NullString{String: value, Valid: value != ""}
+}
+
 // HandleAppUpdate handles app updates.
 func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // validation adds necessary length
 	tmpl := templates.GetParsed()
@@ -257,24 +265,10 @@ func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // valid
 		application.RepoURL = request.FormValue("repo_url")
 		application.Branch = request.FormValue("branch")
 		application.DockerfilePath = request.FormValue("dockerfile_path")
-
-		if network := request.FormValue("docker_network"); network != "" {
-			application.DockerNetwork = sql.NullString{String: network, Valid: true}
-		} else {
-			application.DockerNetwork = sql.NullString{}
-		}
-
-		if ntfy := request.FormValue("ntfy_topic"); ntfy != "" {
-			application.NtfyTopic = sql.NullString{String: ntfy, Valid: true}
-		} else {
-			application.NtfyTopic = sql.NullString{}
-		}
-
-		if slack := request.FormValue("slack_webhook"); slack != "" {
-			application.SlackWebhook = sql.NullString{String: slack, Valid: true}
-		} else {
-			application.SlackWebhook = sql.NullString{}
-		}
+		application.DockerNetwork = optionalNullString(request.FormValue("docker_network"))
+		application.NtfyTopic = optionalNullString(request.FormValue("ntfy_topic"))
+		application.SlackWebhook = optionalNullString(request.FormValue("slack_webhook"))
+		application.HealthcheckCommand = optionalNullString(request.FormValue("healthcheck_command"))
 
 		saveErr := application.Save(request.Context())
 		if saveErr != nil {

internal/models/app.go

@@ -14,7 +14,7 @@ import (
 const appColumns = `id, name, repo_url, branch, dockerfile_path, webhook_secret,
 			ssh_private_key, ssh_public_key, image_id, status,
 			docker_network, ntfy_topic, slack_webhook, webhook_secret_hash,
-			previous_image_id, created_at, updated_at`
+			previous_image_id, healthcheck_command, created_at, updated_at`
 
 // AppStatus represents the status of an app.
 type AppStatus string
@@ -47,6 +47,7 @@ type App struct {
 	DockerNetwork      sql.NullString
 	NtfyTopic          sql.NullString
 	SlackWebhook       sql.NullString
+	HealthcheckCommand sql.NullString
 	CreatedAt          time.Time
 	UpdatedAt          time.Time
 }
@@ -142,14 +143,14 @@ func (a *App) insert(ctx context.Context) error {
 			id, name, repo_url, branch, dockerfile_path, webhook_secret,
 			ssh_private_key, ssh_public_key, image_id, status,
 			docker_network, ntfy_topic, slack_webhook, webhook_secret_hash,
-			previous_image_id
-		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
+			previous_image_id, healthcheck_command
+		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
 
 	_, err := a.db.Exec(ctx, query,
 		a.ID, a.Name, a.RepoURL, a.Branch, a.DockerfilePath, a.WebhookSecret,
 		a.SSHPrivateKey, a.SSHPublicKey, a.ImageID, a.Status,
 		a.DockerNetwork, a.NtfyTopic, a.SlackWebhook, a.WebhookSecretHash,
-		a.PreviousImageID,
+		a.PreviousImageID, a.HealthcheckCommand,
 	)
 	if err != nil {
 		return err
@@ -164,7 +165,7 @@ func (a *App) update(ctx context.Context) error {
 			name = ?, repo_url = ?, branch = ?, dockerfile_path = ?,
 			image_id = ?, status = ?,
 			docker_network = ?, ntfy_topic = ?, slack_webhook = ?,
-			previous_image_id = ?,
+			previous_image_id = ?, healthcheck_command = ?,
 			updated_at = CURRENT_TIMESTAMP
 		WHERE id = ?`
 
@@ -172,7 +173,7 @@ func (a *App) update(ctx context.Context) error {
 		a.Name, a.RepoURL, a.Branch, a.DockerfilePath,
 		a.ImageID, a.Status,
 		a.DockerNetwork, a.NtfyTopic, a.SlackWebhook,
-		a.PreviousImageID,
+		a.PreviousImageID, a.HealthcheckCommand,
 		a.ID,
 	)
 
@@ -187,7 +188,7 @@ func (a *App) scan(row *sql.Row) error {
 		&a.ImageID, &a.Status,
 		&a.DockerNetwork, &a.NtfyTopic, &a.SlackWebhook,
 		&a.WebhookSecretHash,
-		&a.PreviousImageID,
+		&a.PreviousImageID, &a.HealthcheckCommand,
 		&a.CreatedAt, &a.UpdatedAt,
 	)
 }
@@ -205,7 +206,7 @@ func scanApps(appDB *database.Database, rows *sql.Rows) ([]*App, error) {
 			&app.ImageID, &app.Status,
 			&app.DockerNetwork, &app.NtfyTopic, &app.SlackWebhook,
 			&app.WebhookSecretHash,
-			&app.PreviousImageID,
+			&app.PreviousImageID, &app.HealthcheckCommand,
 			&app.CreatedAt, &app.UpdatedAt,
 		)
 		if scanErr != nil {

internal/models/models_test.go

@@ -704,6 +704,72 @@ func TestAppGetWebhookEvents(t *testing.T) {
 	assert.Len(t, events, 1)
 }
 
+// App HealthcheckCommand Tests.
+
+func TestAppHealthcheckCommand(t *testing.T) {
+	t.Parallel()
+
+	t.Run("saves and loads healthcheck command", func(t *testing.T) {
+		t.Parallel()
+
+		testDB, cleanup := setupTestDB(t)
+		defer cleanup()
+
+		app := createTestApp(t, testDB)
+		app.HealthcheckCommand = sql.NullString{
+			String: "curl -f http://localhost:8080/healthz || exit 1",
+			Valid:  true,
+		}
+
+		err := app.Save(context.Background())
+		require.NoError(t, err)
+
+		found, err := models.FindApp(context.Background(), testDB, app.ID)
+		require.NoError(t, err)
+		require.NotNil(t, found)
+		assert.True(t, found.HealthcheckCommand.Valid)
+		assert.Equal(t, "curl -f http://localhost:8080/healthz || exit 1", found.HealthcheckCommand.String)
+	})
+
+	t.Run("null when not set", func(t *testing.T) {
+		t.Parallel()
+
+		testDB, cleanup := setupTestDB(t)
+		defer cleanup()
+
+		app := createTestApp(t, testDB)
+
+		found, err := models.FindApp(context.Background(), testDB, app.ID)
+		require.NoError(t, err)
+		require.NotNil(t, found)
+		assert.False(t, found.HealthcheckCommand.Valid)
+	})
+
+	t.Run("can be cleared", func(t *testing.T) {
+		t.Parallel()
+
+		testDB, cleanup := setupTestDB(t)
+		defer cleanup()
+
+		app := createTestApp(t, testDB)
+		app.HealthcheckCommand = sql.NullString{String: "true", Valid: true}
+
+		err := app.Save(context.Background())
+		require.NoError(t, err)
+
+		// Clear it
+		app.HealthcheckCommand = sql.NullString{}
+
+		err = app.Save(context.Background())
+		require.NoError(t, err)
+
+		found, err := models.FindApp(context.Background(), testDB, app.ID)
+		require.NoError(t, err)
+		require.NotNil(t, found)
+		assert.False(t, found.HealthcheckCommand.Valid)
+	})
+}
+
 // Cascade Delete Tests.
 
 //nolint:funlen // Test function with many assertions - acceptable for integration tests

internal/service/app/app.go

@@ -53,6 +53,7 @@ type CreateAppInput struct {
 	DockerNetwork      string
 	NtfyTopic          string
 	SlackWebhook       string
+	HealthcheckCommand string
 }
 
 // CreateApp creates a new application with generated SSH keys and webhook secret.
@@ -100,6 +101,10 @@ func (svc *Service) CreateApp(
 		app.SlackWebhook = sql.NullString{String: input.SlackWebhook, Valid: true}
 	}
 
+	if input.HealthcheckCommand != "" {
+		app.HealthcheckCommand = sql.NullString{String: input.HealthcheckCommand, Valid: true}
+	}
+
 	saveErr := app.Save(ctx)
 	if saveErr != nil {
 		return nil, fmt.Errorf("failed to save app: %w", saveErr)
@@ -119,6 +124,7 @@ type UpdateAppInput struct {
 	DockerNetwork      string
 	NtfyTopic          string
 	SlackWebhook       string
+	HealthcheckCommand string
 }
 
 // UpdateApp updates an existing application.
@@ -144,6 +150,10 @@ func (svc *Service) UpdateApp(
 		String: input.SlackWebhook,
 		Valid:  input.SlackWebhook != "",
 	}
+	app.HealthcheckCommand = sql.NullString{
+		String: input.HealthcheckCommand,
+		Valid:  input.HealthcheckCommand != "",
+	}
 
 	saveErr := app.Save(ctx)
 	if saveErr != nil {

internal/service/deploy/deploy.go

@@ -1094,6 +1094,11 @@ func (svc *Service) buildContainerOptions(
 		network = app.DockerNetwork.String
 	}
 
+	healthcheckCmd := ""
+	if app.HealthcheckCommand.Valid {
+		healthcheckCmd = app.HealthcheckCommand.String
+	}
+
 	return docker.CreateContainerOptions{
 		Name:               "upaas-" + app.Name,
 		Image:              imageID.String(),
@@ -1102,6 +1107,7 @@ func (svc *Service) buildContainerOptions(
 		Volumes:            buildVolumeMounts(volumes),
 		Ports:              buildPortMappings(ports),
 		Network:            network,
+		HealthcheckCommand: healthcheckCmd,
 	}, nil
 }
 

internal/service/deploy/deploy_container_test.go

@@ -2,6 +2,7 @@ package deploy_test
 
 import (
 	"context"
+	"database/sql"
 	"log/slog"
 	"os"
 	"testing"
@@ -43,3 +44,64 @@ func TestBuildContainerOptionsUsesImageID(t *testing.T) {
 		t.Errorf("expected Name=%q, got %q", "upaas-myapp", opts.Name)
 	}
 }
+
+func TestBuildContainerOptionsHealthcheckSet(t *testing.T) {
+	t.Parallel()
+
+	db := database.NewTestDatabase(t)
+
+	app := models.NewApp(db)
+	app.Name = "hc-app"
+	app.HealthcheckCommand = sql.NullString{
+		String: "curl -f http://localhost:8080/healthz || exit 1",
+		Valid:  true,
+	}
+
+	err := app.Save(context.Background())
+	if err != nil {
+		t.Fatalf("failed to save app: %v", err)
+	}
+
+	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	svc := deploy.NewTestService(log)
+
+	opts, err := svc.BuildContainerOptionsExported(
+		context.Background(), app, "sha256:test",
+	)
+	if err != nil {
+		t.Fatalf("buildContainerOptions returned error: %v", err)
+	}
+
+	expected := "curl -f http://localhost:8080/healthz || exit 1"
+	if opts.HealthcheckCommand != expected {
+		t.Errorf("expected HealthcheckCommand=%q, got %q", expected, opts.HealthcheckCommand)
+	}
+}
+
+func TestBuildContainerOptionsHealthcheckEmpty(t *testing.T) {
+	t.Parallel()
+
+	db := database.NewTestDatabase(t)
+
+	app := models.NewApp(db)
+	app.Name = "no-hc-app"
+
+	err := app.Save(context.Background())
+	if err != nil {
+		t.Fatalf("failed to save app: %v", err)
+	}
+
+	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	svc := deploy.NewTestService(log)
+
+	opts, err := svc.BuildContainerOptionsExported(
+		context.Background(), app, "sha256:test",
+	)
+	if err != nil {
+		t.Fatalf("buildContainerOptions returned error: %v", err)
+	}
+
+	if opts.HealthcheckCommand != "" {
+		t.Errorf("expected empty HealthcheckCommand, got %q", opts.HealthcheckCommand)
+	}
+}

templates/app_edit.html

@@ -114,6 +114,19 @@
                 >
             </div>
 
+            <div class="form-group">
+                <label for="healthcheck_command" class="label">Health Check Command</label>
+                <input
+                    type="text"
+                    id="healthcheck_command"
+                    name="healthcheck_command"
+                    value="{{if .App.HealthcheckCommand.Valid}}{{.App.HealthcheckCommand.String}}{{end}}"
+                    class="input font-mono"
+                    placeholder="curl -f http://localhost:8080/healthz || exit 1"
+                >
+                <p class="text-sm text-gray-500 mt-1">Custom shell command to check container health. Leave empty to use the image's default health check.</p>
+            </div>
+
             <div class="flex justify-end gap-3 pt-4">
                 <a href="/apps/{{.App.ID}}" class="btn-secondary">Cancel</a>
                 <button type="submit" class="btn-primary">Save Changes</button>

templates/app_new.html

@@ -117,6 +117,19 @@
                 >
             </div>
 
+            <div class="form-group">
+                <label for="healthcheck_command" class="label">Health Check Command</label>
+                <input
+                    type="text"
+                    id="healthcheck_command"
+                    name="healthcheck_command"
+                    value="{{.HealthcheckCommand}}"
+                    class="input font-mono"
+                    placeholder="curl -f http://localhost:8080/healthz || exit 1"
+                >
+                <p class="text-sm text-gray-500 mt-1">Custom shell command to check container health. Leave empty to use the image's default health check.</p>
+            </div>
+
             <div class="flex justify-end gap-3 pt-4">
                 <a href="/" class="btn-secondary">Cancel</a>
                 <button type="submit" class="btn-primary">Create App</button>