Update to new NGINX Go SDK

Author: Dean-Coakley

.gitignore

@@ -1,2 +1,3 @@
 /build
+.DS_Store
 

Makefile

@@ -1,5 +1,5 @@
 GO_DOCKER_RUN = docker run --rm -v $(shell pwd)/cmd/sync:/go/src/github.com/nginxinc/nginx-asg-sync/cmd/sync -v $(shell pwd)/build:/build -w /go/src/github.com/nginxinc/nginx-asg-sync/cmd/sync
-GOLANG_CONTAINER = golang:1.8
+GOLANG_CONTAINER = golang:1.10
 
 all: amazon centos7 ubuntu-trusty ubuntu-xenial
 

README.md

@@ -1,21 +1,34 @@
 # NGINX Plus Integration with AWS Auto Scaling groups -- nginx-asg-sync
 
-**nginx-asg-sync** allows [NGINX Plus](https://www.nginx.com/products/) to support scaling when load balancing [AWS Auto Scaling groups](http://docs.aws.amazon.com/autoscaling/latest/userguide/WhatIsAutoScaling.html): when the number of instances in an Auto Scaling group changes, nginx-asg-sync adds the new instances to the NGINX Plus configuration and removes the terminated ones.
+**nginx-asg-sync** allows [NGINX Plus](https://www.nginx.com/products/) to discover instances of [AWS Auto Scaling groups](http://docs.aws.amazon.com/autoscaling/latest/userguide/WhatIsAutoScaling.html). When the number of instances in an Auto Scaling group changes, nginx-asg-sync adds the new instances to the NGINX Plus configuration and removes the terminated ones.
 
-More details on this solution are available in the blog post [Load Balancing AWS Auto Scaling Groups with NGINX Plus](https://www.nginx.com/blog/load-balancing-aws-auto-scaling-groups-nginx-plus/).
+## How It Works
+nginx-asg-sync must be installed on the same EC2 instance with NGINX Plus. nginx-asg-sync constantly monitors backend Auto Scaling groups via the AWS Auto Scaling API.
+When it sees that a scaling event has happened, it adds or removes the corresponding backend instances from the NGINX Plus configuration via the NGINX Plus API.
 
-Below you will find instructions on how to use nginx-asg-sync.
+**Note:** nginx-asg-sync does not scale Auto Scaling groups, it only gets the IP addresses of the instances of Auto Scaling groups.
 
-## Contents
+In the example below, NGINX Plus is configured to load balance among the instances of two Auto Scaling groups -- Backend One and Backend Two.
+nginx-asg-sync, running on the same instance as NGINX Plus, ensures that whenever you scale the Auto Scaling groups, the corresponding instances are added (or removed) from the NGINX Plus configuration.
 
-1. [Supported Operating Systems](#supported-operating-systems)
-1. [Setting up Access to the AWS API](#setting-up-access-to-the-aws-api)
-1. [Installation](#installation)
-1. [Configuration](#configuration)
-1. [Usage](#usage)
-1. [Troubleshooting](#troubleshooting)
-1. [Building a Software Package](#building-a-software-package)
-1. [Support](#support)
+![nginx-asg-sync-architecture](https://cdn-1.wp.nginx.com/wp-content/uploads/2017/03/aws-auto-scaling-group-asg-sync.png)
+
+Below you will find documentation on how to use nginx-asg-sync.
+
+## Documentation
+**Note:** the documentation for **the latest stable release** is available via a link in the description of the release. See the [releases page](https://github.com/nginxinc/nginx-asg-sync/releases).
+
+**Contents:**
+- [Supported Operating Systems](#supported-operating-systems)
+- [Setting up Access to the AWS API](#setting-up-access-to-the-aws-api)
+- [Installation](#installation)
+- [Configuration](#configuration)
+  - [NGINX Plus Configuration](#nginx-plus-configuration)
+  - [nginx-asg-sync Configuration](#nginx-asg-sync-configuration)
+- [Usage](#usage)
+- [Troubleshooting](#troubleshooting)
+- [Building a Software Package](#building-a-software-package)
+- [Support](#support)
 
 ## Supported Operating Systems
 
@@ -34,18 +47,14 @@ nginx-asg-sync uses the AWS API to get the list of IP addresses of the instances
 1. [Create an IAM role](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html) and attach the predefined `AmazonEC2ReadOnlyAccess` policy to it. This policy allows read-only access to EC2 APIs.
 1. When you launch the NGINX Plus instance, add this IAM role to the instance.
 
-Alternatively, you can use the `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` environmental variables to provide credentials to nginx-asg-sync.
-
 ## Installation
 
-To install nginx-asg-sync:
-
-1. Download a software package for your OS with the latest version of nginx-asg-sync from the [Releases page](https://github.com/nginxinc/nginx-asg-sync/releases).
-1. Install the package:
-
-  For Amazon Linux or CentOS/RHEL, run: `$ sudo rpm -i <package-name>.rpm`
-
-  For Ubuntu, run: `$ sudo dpkg -i <package-name>.deb`
+1. Get a software package for your OS:
+    * For a stable release, download a package from the [releases page](https://github.com/nginxinc/nginx-asg-sync/releases).
+    * For the latest source code from the master branch, build a software package by following [these instructions](#building-a-software-package).
+2. Install the package:
+    * For Amazon Linux or CentOS/RHEL, run: `$ sudo rpm -i <package-name>.rpm`
+    * For Ubuntu, run: `$ sudo dpkg -i <package-name>.deb`
 
 ## Configuration
 
@@ -54,6 +63,8 @@ As an example, we configure NGINX Plus to load balance two AWS Auto Scaling grou
 * Requests for /backend-one go to Backend One group.
 * Requests for /backend-two go to Backend Two group.
 
+This example corresponds to [the diagram](#how-it-works) at the top of this README.
+
 ### NGINX Plus Configuration
 
 ```nginx
@@ -86,40 +97,28 @@ server {
 server {
     listen 8080;
 
-    root /usr/share/nginx/html;
-
-    location = / {
-        return 302 /status.html;
-    }
-
-    location = /status.html {
-    }
-
-    location /status {
-        access_log off;
-        status;
+    location /api {
+        api write=on;
     }
 
-    location /upstream_conf {
-        upstream_conf;
+    location /dashboard.html {
+      root /usr/share/nginx/html;
     }
 }
 ```
 
 * We declare two upstream groups – **backend-one** and **backend-two**, which correspond to our Auto Scaling groups. However, we do not add any servers to the upstream groups, because the servers will be added by nginx-aws-sync. The `state` directive names the file where the dynamically configurable list of servers is stored, enabling it to persist across restarts of NGINX Plus.
 * We define a virtual server that listens on port 80. NGINX Plus passes requests for **/backend-one** to the instances of the Backend One group, and requests for **/backend-two** to the instances of the Backend Two group.
-* We define a second virtual server listening on port 8080 and configure the NGINX Plus APIs on it, which are required by nginx-asg-sync:
-  * The on-the-fly API is available at **127.0.0.1:8080/upstream_conf**
-  * The status API is available at **127.0.0.1:8080/status**
+* We define a second virtual server listening on port 8080 and configure the NGINX Plus API on it, which is required by nginx-asg-sync:
+  * The API is available at **127.0.0.1:8080/api**
 
 ### nginx-asg-sync Configuration
 
 nginx-asg-sync is configured in the file **aws.yaml** in the **/etc/nginx** folder. For our example, we define the following configuration:
 
 ```yaml
 region: us-west-2
-upstream_conf_endpoint: http://127.0.0.1:8080/upstream_conf
-status_endpoint: http://127.0.0.1:8080/status
+api_endpoint: http://127.0.0.1:8080/api
 sync_interval_in_seconds: 5
 upstreams:
  - name: backend-one
@@ -133,13 +132,13 @@ upstreams:
 ```
 
 * The `region` key defines the AWS region where we deploy NGINX Plus and the Auto Scaling groups.
-* The `upstream_conf` and the `status_endpoint` keys define the NGINX Plus API endpoints.
+* The `api_endpoint` key defines the NGINX Plus API endpoint.
 * The `sync_interval_in_seconds` key defines the synchronization interval: nginx-asg-sync checks for scaling updates every 5 seconds.
 * The `upstreams` key defines the list of upstream groups. For each upstream group we specify:
   * `name` – The name we specified for the upstream block in the NGINX Plus configuration.
   * `autoscaling_group` – The name of the corresponding Auto Scaling group.
   * `port` – The port on which our backend applications are exposed.
-  * `protocol` – The protocol of the traffic NGINX Plus load balances to the backend application, here `http`. If the application uses TCP/UDP, specify `stream` instead.
+  * `kind` – The protocol of the traffic NGINX Plus load balances to the backend application, here `http`. If the application uses TCP/UDP, specify `stream` instead.
 
 ## Usage
 

cmd/sync/config.go

@@ -9,8 +9,7 @@ import (
 
 type config struct {
 	Region                string
-	UpstreamConfEndpont   string        `yaml:"upstream_conf_endpoint"`
-	StatusEndpoint        string        `yaml:"status_endpoint"`
+	APIEndpoint           string        `yaml:"api_endpoint"`
 	SyncIntervalInSeconds time.Duration `yaml:"sync_interval_in_seconds"`
 	Upstreams             []upstream
 }
@@ -58,11 +57,8 @@ func validateConfig(cfg *config) error {
 	if cfg.Region == "" {
 		return fmt.Errorf(errorMsgFormat, "region")
 	}
-	if cfg.UpstreamConfEndpont == "" {
-		return fmt.Errorf(errorMsgFormat, "upstream_conf_endpoint")
-	}
-	if cfg.StatusEndpoint == "" {
-		return fmt.Errorf(errorMsgFormat, "status_endpoint")
+	if cfg.APIEndpoint == "" {
+		return fmt.Errorf(errorMsgFormat, "api_endpoint")
 	}
 	if cfg.SyncIntervalInSeconds == 0 {
 		return fmt.Errorf(intervalErrorMsg)

cmd/sync/config_test.go

@@ -3,8 +3,7 @@ package main
 import "testing"
 
 var validYaml = []byte(`region: us-west-2
-upstream_conf_endpoint: http://127.0.0.1:8080/upstream_conf
-status_endpoint: http://127.0.0.1:8080/status
+api_endpoint: http://127.0.0.1:8080/api
 sync_interval_in_seconds: 5
 upstreams:
   - name: backend1
@@ -33,8 +32,7 @@ func getValidConfig() *config {
 	}
 	cfg := config{
 		Region:                "us-west-2",
-		UpstreamConfEndpont:   "http://127.0.0.1:8080/upstream_conf",
-		StatusEndpoint:        "http://127.0.0.1:8080/status",
+		APIEndpoint:           "http://127.0.0.1:8080/api",
 		SyncIntervalInSeconds: 1,
 		Upstreams:             upstreams,
 	}
@@ -49,14 +47,6 @@ func getInvalidConfigInput() []*testInput {
 	invalidRegionCfg.Region = ""
 	input = append(input, &testInput{invalidRegionCfg, "invalid region"})
 
-	invalidUpstreamConfEndponCfg := getValidConfig()
-	invalidUpstreamConfEndponCfg.UpstreamConfEndpont = ""
-	input = append(input, &testInput{invalidUpstreamConfEndponCfg, "invalid upstream_conf_endpoint"})
-
-	invalidStatusEndpointCfg := getValidConfig()
-	invalidStatusEndpointCfg.StatusEndpoint = ""
-	input = append(input, &testInput{invalidStatusEndpointCfg, "invalid status_endpoint"})
-
 	invalidSyncIntervalInSecondsCfg := getValidConfig()
 	invalidSyncIntervalInSecondsCfg.SyncIntervalInSeconds = 0
 	input = append(input, &testInput{invalidSyncIntervalInSecondsCfg, "invalid sync_interval_in_seconds"})

cmd/sync/main.go

@@ -50,7 +50,9 @@ func main() {
 		os.Exit(10)
 	}
 
-	nginx, err := NewNginxClient(cfg.UpstreamConfEndpont, cfg.StatusEndpoint, connTimeoutInSecs*time.Second)
+	httpClient := &http.Client{Timeout: connTimeoutInSecs * time.Second}
+	nginx, err := NewNginxClient(httpClient, cfg.APIEndpoint)
+
 	if err != nil {
 		log.Printf("Couldn't create NGINX client: %v", err)
 		os.Exit(10)
@@ -60,10 +62,11 @@ func main() {
 
 	for _, ups := range cfg.Upstreams {
 		if ups.Kind == "http" {
-			err = nginx.CheckIfHTTPUpstreamExists(ups.Name)
+			err = nginx.CheckIfUpstreamExists(ups.Name)
 		} else {
 			err = nginx.CheckIfStreamUpstreamExists(ups.Name)
 		}
+
 		if err != nil {
 			log.Printf("Problem with the NGINX configuration: %v", err)
 			os.Exit(10)
@@ -81,33 +84,53 @@ func main() {
 	signal.Notify(sigterm, syscall.SIGTERM)
 
 	for {
-		for _, ups := range cfg.Upstreams {
-			ips, err := awsClient.GetPrivateIPsOfInstancesOfAutoscalingGroup(ups.AutoscalingGroup)
+		for _, upstream := range cfg.Upstreams {
+			ips, err := awsClient.GetPrivateIPsOfInstancesOfAutoscalingGroup(upstream.AutoscalingGroup)
 			if err != nil {
-				log.Printf("Couldn't get the IP addresses of instances of the Auto Scaling group %v: %v", ups.AutoscalingGroup, err)
+				log.Printf("Couldn't get the IP addresses of instances of the Auto Scaling group %v: %v", upstream.AutoscalingGroup, err)
 				continue
 			}
 
-			var backends []string
-			for _, ip := range ips {
-				backend := fmt.Sprintf("%v:%v", ip, ups.Port)
-				backends = append(backends, backend)
-			}
-
-			var added, removed []string
-
-			if ups.Kind == "http" {
-				added, removed, err = nginx.UpdateHTTPServers(ups.Name, backends)
+			if upstream.Kind == "http" {
+				var upsServers []UpstreamServer
+				for _, ip := range ips {
+					backend := fmt.Sprintf("%v:%v", ip, upstream.Port)
+					upsServers = append(upsServers, UpstreamServer{
+						Server:   backend,
+						MaxFails: 1,
+					})
+				}
+
+				added, removed, err := nginx.UpdateHTTPServers(upstream.Name, upsServers)
+				if err != nil {
+					log.Printf("Couldn't update HTTP servers in NGINX: %v", err)
+					continue
+				}
+
+				if len(added) > 0 || len(removed) > 0 {
+					log.Printf("Updated HTTP servers of %v; Added: %v, Removed: %v", upstream, added, removed)
+				}
 			} else {
-				added, removed, err = nginx.UpdateStreamServers(ups.Name, backends)
-			}
-			if err != nil {
-				log.Printf("Couldn't update servers in NGINX: %v", err)
-				continue
-			}
-			if len(removed) > 0 || len(added) > 0 {
-				log.Printf("Upstream: %v has been updated; Added: %v; Removed: %v\n", ups.Name, added, removed)
+				var upsServers []StreamUpstreamServer
+				for _, ip := range ips {
+					backend := fmt.Sprintf("%v:%v", ip, upstream.Port)
+					upsServers = append(upsServers, StreamUpstreamServer{
+						Server:   backend,
+						MaxFails: 1,
+					})
+				}
+
+				added, removed, err := nginx.UpdateStreamServers(upstream.Name, upsServers)
+				if err != nil {
+					log.Printf("Couldn't update Steam servers in NGINX: %v", err)
+					continue
+				}
+
+				if len(added) > 0 || len(removed) > 0 {
+					log.Printf("Updated Stream servers of %v; Added: %v, Removed: %v", upstream, added, removed)
+				}
 			}
+
 		}
 
 		select {