feat: add HTTP keep-alive support to HAProxy backend configuration (#108)

* feat: add HTTP keep-alive support to HAProxy backend configuration

* fix(haproxy): gate http-keep-alive on http mode; clean up keep-alive test

Address Copilot review findings on PR #108:

- Only emit `option http-keep-alive` when backend.Mode == "http"; emitting
  it for tcp-mode backends produces an invalid stanza.
- Drop BackendSSL from the keep-alive test (it was generating `verify`
  with an empty value, unrelated to keep-alive). Add a separate test
  asserting the directive is suppressed for tcp-mode backends.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: sarg3nt

gearbox-agent/internal/framework/services/compose/parser.go

@@ -124,6 +124,7 @@ type BackendConfig struct {
 	ACLIP            string      `json:"acl_ip,omitempty"`
 	BackendSSL       bool        `json:"backend_ssl"`
 	BackendSSLVerify string      `json:"backend_ssl_verify"`
+	HTTPKeepAlive    bool        `json:"http_keep_alive"`
 }
 
 // Container represents a container in a Docker Compose service.
@@ -142,7 +143,7 @@ type ComposeFile struct {
 // Service represents a service in a docker-compose.yml file.
 type Service struct {
 	Labels      any            `yaml:"labels"`
-	NetworkMode string                 `yaml:"network_mode"`
+	NetworkMode string         `yaml:"network_mode"`
 	DependsOn   any            `yaml:"depends_on"`
 	Other       map[string]any `yaml:",inline"`
 }
@@ -378,6 +379,7 @@ func (p *Parser) extractBackendConfig(labels map[string]string, appName, service
 		ACLIP:            aclIP,
 		BackendSSL:       labels[LabelPrefix+"backend.ssl"] == "true",
 		BackendSSLVerify: sslVerify,
+		HTTPKeepAlive:    labels[LabelPrefix+"backend.http_keep_alive"] == "true",
 	}
 
 	return config

gearbox-agent/internal/framework/services/compose/parser_test.go

@@ -74,28 +74,27 @@ func TestParseFile_AllLabels(t *testing.T) {
 		t.Fatalf("Failed to create app dir: %v", err)
 	}
 
-	composeContent := `
-services:
-  api:
-    image: api:latest
-    labels:
-      haproxy.enable: "true"
-      haproxy.hostname: "api.example.com"
-      haproxy.backend.server: "api:3000"
-      haproxy.backend.name: "custom_backend"
-      haproxy.backend.mode: "http"
-      haproxy.backend.balance: "leastconn"
-      haproxy.backend.check: "true"
-      haproxy.backend.check.interval: "10s"
-      haproxy.backend.check.fall: "5"
-      haproxy.backend.check.rise: "3"
-      haproxy.ssl.redirect: "true"
-      haproxy.public: "true"
-      haproxy.rate_limit: "200"
-      haproxy.acl.ip: "10.0.0.0/8"
-      haproxy.backend.ssl: "true"
-      haproxy.backend.ssl.verify: "required"
-`
+	composeContent := "services:\n" +
+		"  api:\n" +
+		"    image: api:latest\n" +
+		"    labels:\n" +
+		"      haproxy.enable: \"true\"\n" +
+		"      haproxy.hostname: \"api.example.com\"\n" +
+		"      haproxy.backend.server: \"api:3000\"\n" +
+		"      haproxy.backend.name: \"custom_backend\"\n" +
+		"      haproxy.backend.mode: \"http\"\n" +
+		"      haproxy.backend.balance: \"leastconn\"\n" +
+		"      haproxy.backend.check: \"true\"\n" +
+		"      haproxy.backend.check.interval: \"10s\"\n" +
+		"      haproxy.backend.check.fall: \"5\"\n" +
+		"      haproxy.backend.check.rise: \"3\"\n" +
+		"      haproxy.ssl.redirect: \"true\"\n" +
+		"      haproxy.public: \"true\"\n" +
+		"      haproxy.rate_limit: \"200\"\n" +
+		"      haproxy.acl.ip: \"10.0.0.0/8\"\n" +
+		"      haproxy.backend.ssl: \"true\"\n" +
+		"      haproxy.backend.ssl.verify: \"required\"\n" +
+		"      haproxy.backend.http_keep_alive: \"true\"\n"
 	composePath := filepath.Join(appDir, "docker-compose.yml")
 	if err := os.WriteFile(composePath, []byte(composeContent), 0644); err != nil {
 		t.Fatalf("Failed to write compose file: %v", err)
@@ -151,6 +150,9 @@ services:
 	if b.BackendSSLVerify != "required" {
 		t.Errorf("BackendSSLVerify = %q, want %q", b.BackendSSLVerify, "required")
 	}
+	if !b.HTTPKeepAlive {
+		t.Error("HTTPKeepAlive should be true")
+	}
 }
 
 func TestParseFile_DisabledService(t *testing.T) {
@@ -516,9 +518,9 @@ func TestGetOrDefault(t *testing.T) {
 	}
 
 	tests := []struct {
-		key      string
-		defVal   string
-		want     string
+		key    string
+		defVal string
+		want   string
 	}{
 		{"key1", "default", "value1"},
 		{"key2", "default", "default"}, // Empty string uses default

gearbox-agent/internal/framework/services/haproxy/generator.go

@@ -120,6 +120,9 @@ func (g *Generator) GenerateBackendConfig() string {
 		lines = append(lines, fmt.Sprintf("backend %s", backend.BackendName))
 		lines = append(lines, fmt.Sprintf("  mode %s", backend.Mode))
 		lines = append(lines, fmt.Sprintf("  balance %s", backend.Balance))
+		if backend.HTTPKeepAlive && backend.Mode == "http" {
+			lines = append(lines, "  option http-keep-alive")
+		}
 
 		// Build server options
 		var serverOpts []string

gearbox-agent/internal/framework/services/haproxy/generator_test.go

@@ -322,15 +322,15 @@ func TestGenerator_GenerateBackendConfig_NoCheck(t *testing.T) {
 func TestGenerator_GenerateBackendConfig_TCPMode(t *testing.T) {
 	backends := []compose.BackendConfig{
 		{
-			BackendName: "tcp_backend",
-			Hostname:    "tcp.example.com",
-			Server:      "tcp-server:3306",
-			Mode:        "tcp",
-			Balance:     "leastconn",
-			Check:       true,
+			BackendName:   "tcp_backend",
+			Hostname:      "tcp.example.com",
+			Server:        "tcp-server:3306",
+			Mode:          "tcp",
+			Balance:       "leastconn",
+			Check:         true,
 			CheckInterval: "10s",
-			CheckFall:   "2",
-			CheckRise:   "3",
+			CheckFall:     "2",
+			CheckRise:     "3",
 		},
 	}
 
@@ -459,3 +459,43 @@ func TestGenerator_GenerateBackendConfig_SSLWithRequiredVerify(t *testing.T) {
 		t.Error("GenerateBackendConfig() missing 'verify required' option")
 	}
 }
+
+func TestGenerator_GenerateBackendConfig_HTTPKeepAlive(t *testing.T) {
+	backends := []compose.BackendConfig{
+		{
+			BackendName:   "keepalive_backend",
+			Hostname:      "idrac.example.com",
+			Server:        "10.0.0.6:443",
+			Mode:          "http",
+			Balance:       "roundrobin",
+			HTTPKeepAlive: true,
+		},
+	}
+
+	gen := NewGenerator(backends)
+	config := gen.GenerateBackendConfig()
+
+	if !strings.Contains(config, "option http-keep-alive") {
+		t.Error("GenerateBackendConfig() missing 'option http-keep-alive' directive")
+	}
+}
+
+func TestGenerator_GenerateBackendConfig_HTTPKeepAlive_TCPModeSkipped(t *testing.T) {
+	backends := []compose.BackendConfig{
+		{
+			BackendName:   "keepalive_tcp_backend",
+			Hostname:      "tcp.example.com",
+			Server:        "10.0.0.7:3306",
+			Mode:          "tcp",
+			Balance:       "roundrobin",
+			HTTPKeepAlive: true,
+		},
+	}
+
+	gen := NewGenerator(backends)
+	config := gen.GenerateBackendConfig()
+
+	if strings.Contains(config, "option http-keep-alive") {
+		t.Error("GenerateBackendConfig() emitted 'option http-keep-alive' for tcp-mode backend")
+	}
+}