Merge pull request #23 from MatinRh/master

ElasticSearch support

README.md

@@ -16,6 +16,7 @@ It also supports **timeout** so it can wait for a particular time and then fail.
 * Redis
 * RabbitMQ
 * Memcached
+* ElasticSearch
 
 ## Install
 You can download the latest [release](https://github.com/ph4r5h4d/wait4it/releases), or you can build it yourself.
@@ -98,6 +99,11 @@ Check a Memcached instance
 ./wait4it -type=memcached -h=127.0.0.1 -p=11211 -t=60
 ```
 
+Check ElasticSearch instance
+```bash
+./wait4it -type=elasticsearch -h=http://127.0.0.1 -p=9200 -t=60
+```
+
 ### Docker
 You can run this `wait4it` inside a docker container, and it's possible to run this container as init container inside
 K8s and Openshift.  
@@ -153,6 +159,11 @@ Check a Memcached instance
 docker run ph4r5h4d/wait4it -type=memcached -h=127.0.0.1 -p=11211
 ```
 
+Check a ElasticSearch instance
+```bash
+docker run ph4r5h4d/wait4it -type=elasticsearch -h=http://127.0.0.1 -p=9200
+```
+
 ## Notes
 #### Configuration
 * note that environment variables have higher priority than command-line arguments. 
@@ -178,4 +189,8 @@ This means if you define both `W4IT_TYPE` and `-type`, the application takes the
 * this version can only check one host within Redis cluster, using multiple hosts to check cluster status for Redis will be added in the next version.
 
 #### Memcached check
-* for the moment multiple hosts and cluster check is not supported.
+* for the moment multiple hosts and cluster checks are not supported.
+
+#### ElasticSearch
+* for the moment multiple hosts and cluster checks are not supported.
+* as you know, username/password authentication mechanism is only supported along with the X-Pack extension and if the X-Pack extension wasn't activated, filling username/password won't have any effect. According to these reasons, username/password isn't required.

cmd/check-cmd.go

@@ -36,7 +36,7 @@ func RunCheck(c model.CheckContext) {
 	time.Sleep(time.Duration(c.Config.Timeout) * time.Second)
 	done <- true
 
-	fmt.Print("failed")
+	fmt.Println("failed")
 	os.Exit(1)
 }
 

cmd/check-module-list.go

@@ -7,17 +7,19 @@ import (
 	"wait4it/PostgreSQLChecker"
 	"wait4it/RedisChecker"
 	"wait4it/TcpChecker"
+	"wait4it/elasticsearch"
 	"wait4it/httpChecker"
 	"wait4it/rabbitmq"
 )
 
 var cm = map[string]interface{}{
-	"tcp":      &TcpChecker.Tcp{},
-	"mysql":    &MySQLChecker.MySQLConnection{},
-	"postgres": &PostgreSQLChecker.PostgresSQLConnection{},
-	"http":     &httpChecker.HttpCheck{},
-	"mongo":    &MongoDbChecker.MongoDbConnection{},
-	"redis":    &RedisChecker.RedisConnection{},
-	"rabbitmq": &rabbitmq.RabbitChecker{},
-  "memcached": &MemcachedChecker.MemcachedConnection{},
+	"tcp":           &TcpChecker.Tcp{},
+	"mysql":         &MySQLChecker.MySQLConnection{},
+	"postgres":      &PostgreSQLChecker.PostgresSQLConnection{},
+	"http":          &httpChecker.HttpCheck{},
+	"mongo":         &MongoDbChecker.MongoDbConnection{},
+	"redis":         &RedisChecker.RedisConnection{},
+	"rabbitmq":      &rabbitmq.RabbitChecker{},
+	"memcached":     &MemcachedChecker.MemcachedConnection{},
+	"elasticsearch": &elasticsearch.ElasticSearchChecker{},
 }

cmd/output.std.go

@@ -7,13 +7,13 @@ import (
 
 func wStdOut(r bool) {
 	if r {
-		_, _ = fmt.Fprint(os.Stdout, "succeed")
+		_, _ = fmt.Fprintln(os.Stdout, "succeed")
 		os.Exit(0)
 	} else {
 		_, _ = fmt.Fprint(os.Stdout, ".")
 	}
 }
 
 func wStdErr(a ...interface{}) {
-	_, _ = fmt.Fprint(os.Stderr, a...)
+	_, _ = fmt.Fprintln(os.Stderr, a...)
 }

elasticsearch/elasticsearchchecker.go

@@ -0,0 +1,60 @@
+package elasticsearch
+
+import (
+	"errors"
+	"strconv"
+	"wait4it/model"
+
+	elasticsearch "github.com/elastic/go-elasticsearch/v8"
+)
+
+type ElasticSearchChecker struct {
+	Host     string
+	Port     int
+	Username string
+	Password string
+}
+
+func (esc *ElasticSearchChecker) BuildContext(cx model.CheckContext) {
+	esc.Host = cx.Host
+	esc.Port = cx.Port
+	esc.Username = cx.Username
+	esc.Password = cx.Password
+}
+
+func (esc *ElasticSearchChecker) Validate() error {
+	if len(esc.Host) == 0 {
+		return errors.New("Host can't be empty")
+	}
+
+	if esc.Port < 1 || esc.Port > 65535 {
+		return errors.New("Invalid port range for ElasticSearch")
+	}
+
+	return nil
+}
+
+func (esc *ElasticSearchChecker) Check() (bool, bool, error) {
+	cfg := elasticsearch.Config{
+		Addresses: []string{
+			esc.BuildConnectionString(),
+		},
+		Username: esc.Username,
+		Password: esc.Password,
+	}
+
+	es, err := elasticsearch.NewClient(cfg)
+	if err != nil {
+		return false, true, err
+	}
+
+	if _, err := es.Ping(); err != nil {
+		return false, false, err
+	}
+
+	return true, true, nil
+}
+
+func (esc *ElasticSearchChecker) BuildConnectionString() string {
+	return esc.Host + ":" + strconv.Itoa(esc.Port)
+}

go.mod

@@ -4,6 +4,7 @@ go 1.15
 
 require (
 	github.com/bradfitz/gomemcache v0.0.0-20190913173617-a41fca850d0b
+	github.com/elastic/go-elasticsearch/v8 v8.0.0-20201007143536-4b4020669208
 	github.com/go-redis/redis/v8 v8.0.0-beta.8
 	github.com/go-sql-driver/mysql v1.5.0
 	github.com/lib/pq v1.3.0

go.sum

@@ -16,6 +16,9 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/elastic/go-elasticsearch v0.0.0 h1:Pd5fqOuBxKxv83b0+xOAJDAkziWYwFinWnBO0y+TZaA=
+github.com/elastic/go-elasticsearch/v8 v8.0.0-20201007143536-4b4020669208 h1:e7eoyubUAsH05vn5eMkgMPQO6E+B+CT7yxWbLSQe2xU=
+github.com/elastic/go-elasticsearch/v8 v8.0.0-20201007143536-4b4020669208/go.mod h1:xe9a/L2aeOgFKKgrO3ibQTnMdpAeL0GC+5/HpGScSa4=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=