[nginx-ingress-controller]: Add support for conditional log of urls

ingress/controllers/nginx/nginx.tmpl

@@ -70,7 +70,15 @@ http {
         '[$proxy_add_x_forwarded_for] - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" '
         '$request_length $request_time $upstream_addr $upstream_response_length $upstream_response_time $upstream_status';
 
-    access_log /var/log/nginx/access.log upstreaminfo;
+    {{/* map urls that should not appear in access.log */}}
+    {{/* http://nginx.org/en/docs/http/ngx_http_log_module.html#access_log */}}
+    map $request $loggable {
+        {{- range $reqUri := $cfg.skipAccessLogUrls }}
+        {{ $reqUri }} 0;{{ end }}
+        default 1;
+    }
+
+    access_log /var/log/nginx/access.log upstreaminfo if=$loggable;
     error_log  /var/log/nginx/error.log {{ $cfg.errorLogLevel }};
 
     {{ if not (empty .defResolver) }}# Custom dns resolver.

ingress/controllers/nginx/nginx/config/config.go

@@ -162,6 +162,11 @@ type Configuration struct {
 	// http://nginx.org/en/docs/http/ngx_http_core_module.html#server_names_hash_bucket_size
 	ServerNameHashBucketSize int `structs:"server-name-hash-bucket-size,omitempty"`
 
+	// SkipAccessLogURLs sets a list of URLs that should not appear in the NGINX access log
+	// This is useful with urls like `/health` or `health-check` that make "complex" reading the logs
+	// By default this list is empty
+	SkipAccessLogURLs []string `structs:"skip-access-log-urls,-"`
+
 	// Enables or disables the redirect (301) to the HTTPS port
 	SSLRedirect bool `structs:"ssl-redirect,omitempty"`
 
@@ -275,6 +280,7 @@ func NewDefault() Configuration {
 		UseHTTP2:                 true,
 		CustomHTTPErrors:         make([]int, 0),
 		WhitelistSourceRange:     make([]string, 0),
+		SkipAccessLogURLs:        make([]string, 0),
 	}
 
 	if glog.V(5) {

ingress/controllers/nginx/nginx/utils.go

@@ -33,7 +33,8 @@ import (
 )
 
 const (
-	customHTTPErrors = "custom-http-errors"
+	customHTTPErrors  = "custom-http-errors"
+	skipAccessLogUrls = "skip-access-log-urls"
 )
 
 // getDNSServers returns the list of nameservers located in the file /etc/resolv.conf
@@ -110,6 +111,12 @@ func (ngx *Manager) ReadConfig(conf *api.ConfigMap) config.Configuration {
 		}
 	}
 
+	cSkipUrls := make([]string, 0)
+	if val, ok := conf.Data[skipAccessLogUrls]; ok {
+		delete(conf.Data, skipAccessLogUrls)
+		cSkipUrls = strings.Split(val, ",")
+	}
+
 	err = decoder.Decode(conf.Data)
 	if err != nil {
 		glog.Infof("%v", err)
@@ -135,6 +142,7 @@ func (ngx *Manager) ReadConfig(conf *api.ConfigMap) config.Configuration {
 	}
 
 	cfgDefault.CustomHTTPErrors = ngx.filterErrors(cErrors)
+	cfgDefault.SkipAccessLogURLs = cSkipUrls
 	return cfgDefault
 }