Add fetch custom NGINX template from ConfigMap

examples/custom-templates/README.md

@@ -0,0 +1,54 @@
+# Custom Templates
+
+The Ingress controller allows you to customize your templates through a [ConfigMap](https://github.com/nginxinc/kubernetes-ingress/tree/master/examples/customization) via the following keys:
+* `main-template` - Sets the main NGINX configuration template.
+* `ingress-template` - Sets the Ingress NGINX configuration template for an Ingress resource.
+
+## Example
+```yaml
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: nginx-config
+  namespace: nginx-ingress
+data:
+  main-template: |
+    user  nginx;
+    worker_processes  {{.WorkerProcesses}};
+    ...
+        include /etc/nginx/conf.d/*.conf;
+    }
+  ingress-template: |
+    {{range $upstream := .Upstreams}}
+    upstream {{$upstream.Name}} {
+      {{if $upstream.LBMethod }}{{$upstream.LBMethod}};{{end}}
+    ...
+    }{{end}}
+```
+**Note:** the templates are truncated for the clarity of the example.
+
+## Troubleshooting
+* If a custom template contained within the ConfigMap is invalid on startup, the Ingress controller will fail to start, the error will be reported in the Ingress controller logs.
+
+    An example of an error from the logs:
+    ```
+    Error updating NGINX main template: template: nginxTemplate:98: unexpected EOF
+    ```
+
+* If a custom template contained within the ConfigMap is invalid on update, the Ingress controller will not update the NGINX configuration, the error will be reported in the Ingress controller logs and an event with the error will be associated with the ConfigMap.
+
+    An example of an error from the logs:
+    ```
+    Error when updating config from ConfigMap: Invalid nginx configuration detected, not reloading
+    ```
+
+  An example of an event with an error (you can view events associated with the ConfigMap by running `kubectl describe -n nginx-ingress configmap nginx-config`):
+
+    ```
+    Events:
+      Type     Reason            Age                From                      Message
+      ----     ------            ----               ----                      -------
+      Normal   Updated           12s (x2 over 25s)  nginx-ingress-controller  Configuration from nginx-ingress/nginx-config was updated
+      Warning  UpdatedWithError  10s                nginx-ingress-controller  Configuration from nginx-ingress/nginx-config was updated, but not applied: Error when parsing the main template: template: nginxTemplate:98: unexpected EOF
+      Warning  UpdatedWithError  8s                 nginx-ingress-controller  Configuration from nginx-ingress/nginx-config was updated, but not applied: Error when writing main Config
+    ```

examples/customization/README.md

@@ -37,6 +37,8 @@ The table below summarizes all of the options. For some of them, there are examp
 | `nginx.org/server-tokens` | `server-tokens` | Enables or disables the [server_tokens](http://nginx.org/en/docs/http/ngx_http_core_module.html#server_tokens) directive. Additionally, with the NGINX Plus, you can specify a custom string value, including the empty string value, which disables the emission of the “Server” field. | `True`| |
 | N/A | `main-snippets` | Sets a custom snippet in main context. | N/A | |
 | N/A | `http-snippets` | Sets a custom snippet in http context. | N/A | |
+| N/A | `main-template` | Sets the main NGINX configuration template. | By default the template is read from the file in the container. | [Custom Templates](../custom-templates). |
+| N/A | `ingress-template` | Sets the NGINX configuration template for an Ingress resource. | By default the template is read from the file on the container. | [Custom Templates](../custom-templates). |
 | `nginx.org/location-snippets` | `location-snippets` | Sets a custom snippet in location context. | N/A | |
 | `nginx.org/server-snippets` | `server-snippets` | Sets a custom snippet in server context. | N/A | |
 | `nginx.org/lb-method` | `lb-method` | Sets the [load balancing method](https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/#choosing-a-load-balancing-method). To use the round-robin method, specify `"round_robin"`. | `"least_conn"` | |

nginx-controller/controller/controller_test.go

@@ -548,7 +548,7 @@ func getMergableDefaults() (cafeMaster, coffeeMinion, teaMinion extensions.Ingre
 	cafeMasterIngEx, _ := lbc.createIngress(&cafeMaster)
 	ingExMap["default-cafe-master"] = cafeMasterIngEx
 
-	cnf := nginx.NewConfigurator(&nginx.NginxController{}, &nginx.Config{}, &plus.NginxAPIController{})
+	cnf := nginx.NewConfigurator(&nginx.NginxController{}, &nginx.Config{}, &plus.NginxAPIController{}, &nginx.TemplateExecutor{})
 
 	// edit private field ingresses to use in testing
 	pointerVal := reflect.ValueOf(cnf)
@@ -781,7 +781,7 @@ func TestFindProbeForPods(t *testing.T) {
 
 func TestGetServicePortForIngressPort(t *testing.T) {
 	fakeClient := fake.NewSimpleClientset()
-	cnf := nginx.NewConfigurator(&nginx.NginxController{}, &nginx.Config{}, &plus.NginxAPIController{})
+	cnf := nginx.NewConfigurator(&nginx.NginxController{}, &nginx.Config{}, &plus.NginxAPIController{}, &nginx.TemplateExecutor{})
 	lbc := LoadBalancerController{
 		client:       fakeClient,
 		ingressClass: "nginx",

nginx-controller/main.go

@@ -106,6 +106,10 @@ func main() {
 		nginxConfTemplatePath = "nginx-plus.tmpl"
 		nginxIngressTemplatePath = "nginx-plus.ingress.tmpl"
 	}
+	templateExecutor, err := nginx.NewTemplateExecutor(nginxConfTemplatePath, nginxIngressTemplatePath, *healthStatus)
+	if err != nil {
+		glog.Fatalf("Error creating TemplateExecutor: %v", err)
+	}
 	ngxc, _ := nginx.NewNginxController("/etc/nginx/", local, *healthStatus, nginxConfTemplatePath, nginxIngressTemplatePath)
 
 	if *defaultServerSecret != "" {
@@ -150,9 +154,26 @@ func main() {
 				cfg.MainServerSSLDHParam = fileName
 			}
 		}
+		if cfg.MainTemplate != nil {
+			err = templateExecutor.UpdateMainTemplate(cfg.MainTemplate)
+			if err != nil {
+				glog.Fatalf("Error updating NGINX main template: %v", err)
+			}
+		}
+		if cfg.IngressTemplate != nil {
+			err = templateExecutor.UpdateIngressTemplate(cfg.IngressTemplate)
+			if err != nil {
+				glog.Fatalf("Error updating ingress template: %v", err)
+			}
+		}
 	}
+
 	ngxConfig := nginx.GenerateNginxMainConfig(cfg)
-	ngxc.UpdateMainConfigFile(ngxConfig)
+	content, err := templateExecutor.ExecuteMainConfigTemplate(ngxConfig)
+	if err != nil {
+		glog.Fatalf("Error generating NGINX main config: %v", err)
+	}
+	ngxc.UpdateMainConfigFile(content)
 
 	nginxDone := make(chan error, 1)
 	ngxc.Start(nginxDone)
@@ -166,7 +187,7 @@ func main() {
 		}
 	}
 
-	cnf := nginx.NewConfigurator(ngxc, cfg, nginxAPI)
+	cnf := nginx.NewConfigurator(ngxc, cfg, nginxAPI, templateExecutor)
 	lbc := controller.NewLoadBalancerController(kubeClient, 30*time.Second, *watchNamespace, cnf, *nginxConfigMaps, *defaultServerSecret, *nginxPlus, *ingressClass, *useIngressClassOnly)
 	go handleTermination(lbc, ngxc, nginxDone)
 	lbc.Run()

nginx-controller/nginx/config.go

@@ -60,6 +60,9 @@ type Config struct {
 	MainServerSSLDHParam             string
 	MainServerSSLDHParamFileContent  *string
 
+	MainTemplate    *string
+	IngressTemplate *string
+
 	JWTRealm    string
 	JWTKey      string
 	JWTToken    string
@@ -337,5 +340,11 @@ func ParseConfigMap(cfgm *api_v1.ConfigMap, nginxPlus bool) *Config {
 	if failTimeout, exists := cfgm.Data["fail-timeout"]; exists {
 		cfg.FailTimeout = failTimeout
 	}
+	if mainTemplate, exists := cfgm.Data["main-template"]; exists {
+		cfg.MainTemplate = &mainTemplate
+	}
+	if ingressTemplate, exists := cfgm.Data["ingress-template"]; exists {
+		cfg.IngressTemplate = &ingressTemplate
+	}
 	return cfg
 }

nginx-controller/nginx/configurator.go

@@ -27,19 +27,21 @@ const JWTKeyAnnotation = "nginx.com/jwt-key"
 
 // Configurator transforms an Ingress resource into NGINX Configuration
 type Configurator struct {
-	nginx     *NginxController
-	config    *Config
-	nginxAPI  *plus.NginxAPIController
-	ingresses map[string]*IngressEx
+	nginx            *NginxController
+	config           *Config
+	nginxAPI         *plus.NginxAPIController
+	ingresses        map[string]*IngressEx
+	templateExecutor *TemplateExecutor
 }
 
 // NewConfigurator creates a new Configurator
-func NewConfigurator(nginx *NginxController, config *Config, nginxAPI *plus.NginxAPIController) *Configurator {
+func NewConfigurator(nginx *NginxController, config *Config, nginxAPI *plus.NginxAPIController, templateExecutor *TemplateExecutor) *Configurator {
 	cnf := Configurator{
-		nginx:     nginx,
-		config:    config,
-		nginxAPI:  nginxAPI,
-		ingresses: make(map[string]*IngressEx),
+		nginx:            nginx,
+		config:           config,
+		nginxAPI:         nginxAPI,
+		ingresses:        make(map[string]*IngressEx),
+		templateExecutor: templateExecutor,
 	}
 
 	return &cnf
@@ -60,12 +62,17 @@ func (cnf *Configurator) AddOrUpdateIngress(ingEx *IngressEx) error {
 	return nil
 }
 
-func (cnf *Configurator) addOrUpdateIngress(ingEx *IngressEx) {
+func (cnf *Configurator) addOrUpdateIngress(ingEx *IngressEx) error {
 	pems, jwtKeyFileName := cnf.updateSecrets(ingEx)
 	nginxCfg := cnf.generateNginxCfg(ingEx, pems, jwtKeyFileName)
 	name := objectMetaToFileName(&ingEx.Ingress.ObjectMeta)
-	cnf.nginx.AddOrUpdateIngress(name, nginxCfg)
+	content, err := cnf.templateExecutor.ExecuteIngressConfigTemplate(&nginxCfg)
+	if err != nil {
+		return fmt.Errorf("Error generating Ingress Config %v: %v", name, err)
+	}
+	cnf.nginx.UpdateIngressConfigFile(name, content)
 	cnf.ingresses[name] = ingEx
+	return nil
 }
 
 // AddOrUpdateMergableIngress adds or updates NGINX configuration for the Ingress resources with Mergeable Types
@@ -78,11 +85,16 @@ func (cnf *Configurator) AddOrUpdateMergableIngress(mergeableIngs *MergeableIngr
 	return nil
 }
 
-func (cnf *Configurator) addOrUpdateMergableIngress(mergeableIngs *MergeableIngresses) {
+func (cnf *Configurator) addOrUpdateMergableIngress(mergeableIngs *MergeableIngresses) error {
 	nginxCfg := cnf.generateNginxCfgForMergeableIngresses(mergeableIngs)
 	name := objectMetaToFileName(&mergeableIngs.Master.Ingress.ObjectMeta)
-	cnf.nginx.AddOrUpdateIngress(name, nginxCfg)
+	content, err := cnf.templateExecutor.ExecuteIngressConfigTemplate(&nginxCfg)
+	if err != nil {
+		return fmt.Errorf("Error generating Ingress Config %v: %v", name, err)
+	}
+	cnf.nginx.UpdateIngressConfigFile(name, content)
 	cnf.ingresses[name] = mergeableIngs.Master
+	return nil
 }
 
 func (cnf *Configurator) generateNginxCfgForMergeableIngresses(mergeableIngs *MergeableIngresses) IngressNginxConfig {
@@ -1047,15 +1059,37 @@ func (cnf *Configurator) UpdateConfig(config *Config, ingExes []*IngressEx, merg
 		}
 		config.MainServerSSLDHParam = fileName
 	}
+
+	if config.MainTemplate != nil {
+		err := cnf.templateExecutor.UpdateMainTemplate(config.MainTemplate)
+		if err != nil {
+			return fmt.Errorf("Error when parsing the main template: %v", err)
+		}
+	}
+	if config.IngressTemplate != nil {
+		err := cnf.templateExecutor.UpdateIngressTemplate(config.IngressTemplate)
+		if err != nil {
+			return fmt.Errorf("Error when parsing the ingress template: %v", err)
+		}
+	}
+
 	mainCfg := GenerateNginxMainConfig(config)
-	cnf.nginx.UpdateMainConfigFile(mainCfg)
 
-	for _, ingEx := range ingExes {
-		cnf.addOrUpdateIngress(ingEx)
+	mainCfgContent, err := cnf.templateExecutor.ExecuteMainConfigTemplate(mainCfg)
+	if err != nil {
+		return fmt.Errorf("Error when writing main Config")
 	}
+	cnf.nginx.UpdateMainConfigFile(mainCfgContent)
 
+	for _, ingEx := range ingExes {
+		if err := cnf.addOrUpdateIngress(ingEx); err != nil {
+			return err
+		}
+	}
 	for _, mergeableIng := range mergeableIngs {
-		cnf.addOrUpdateMergableIngress(mergeableIng)
+		if err := cnf.addOrUpdateMergableIngress(mergeableIng); err != nil {
+			return err
+		}
 	}
 
 	if err := cnf.nginx.Reload(); err != nil {