Avoid concurrently status check + Go modules (#9)

* Migrate to go modules

* initial check async + prevent multiple checks on database

.gitignore

@@ -0,0 +1 @@
+coverage.txt

.travis.yml

@@ -3,7 +3,7 @@ go:
 - 1.11
 go_import_path: github.com/StudioSol/balancer
 install:
-  - make dependency
+  - make upgrade
 script:
   - make test
 after_success:

Makefile

@@ -1,7 +1,16 @@
-dependency:
-	go get github.com/smartystreets/goconvey/convey
-	go get gopkg.in/DATA-DOG/go-sqlmock.v1
+export GO111MODULE=on
 
+all: deps build
+install: 
+	go install
+build: 
+	go build
+clean: 
+	go clean
+deps: 
+	go build -v ./...
+upgrade: 
+	go get -u
 test:
 	echo "" > coverage.txt
 	for d in $(shell go list ./...); do \

balancer.go

@@ -74,18 +74,9 @@ func (b *Balancer) serversUP() Servers {
 	return serversUP
 }
 
-func (b *Balancer) initChecks() {
-	for i := range b.servers {
-		b.servers[i].CheckHealth(b.traceOn, b.logger)
-	}
-}
-
-func (b *Balancer) startChecks() {
-	concurrence.Every(time.Duration(b.config.CheckInterval)*time.Second, func(time.Time) bool {
-		b.servers.eachASYNC(func(index int, server *Server) {
-			server.CheckHealth(b.traceOn, b.logger)
-		})
-		return true
+func (b *Balancer) check() {
+	b.servers.eachASYNC(func(index int, server *Server) {
+		server.CheckHealth(b.traceOn, b.logger)
 	})
 }
 
@@ -136,9 +127,12 @@ func New(config *Config) *Balancer {
 		traceOn: config.TraceOn,
 	}
 
-	balancer.initChecks()
+	balancer.check()
 	if config.StartCheck {
-		balancer.startChecks()
+		concurrence.Every(time.Duration(config.CheckInterval)*time.Second, func(time.Time) bool {
+			balancer.check()
+			return true
+		})
 	}
 
 	return balancer

go.mod

@@ -0,0 +1,22 @@
+module github.com/StudioSol/balancer
+
+require (
+	github.com/DATA-DOG/go-sqlmock v1.3.3
+	github.com/go-gorp/gorp v2.0.0+incompatible
+	github.com/go-sql-driver/mysql v1.4.1
+	github.com/golang/protobuf v1.3.1
+	github.com/gopherjs/gopherjs v0.0.0-20190309154008-847fc94819f9 // indirect
+	github.com/lib/pq v1.0.0
+	github.com/mattn/go-sqlite3 v1.10.0
+	github.com/onsi/ginkgo v1.8.0
+	github.com/onsi/gomega v1.5.0
+	github.com/smartystreets/assertions v0.0.0-20190215210624-980c5ac6f3ac // indirect
+	github.com/smartystreets/goconvey v0.0.0-20190306220146-200a235640ff
+	github.com/ziutek/mymysql v0.0.0-20160623123511-8787d5581eb6
+	golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c // indirect
+	golang.org/x/net v0.0.0-20190327091125-710a502c58a2 // indirect
+	golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6 // indirect
+	golang.org/x/sys v0.0.0-20190322080309-f49334f85ddc
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127
+	gopkg.in/yaml.v2 v2.2.2
+)

go.sum

@@ -0,0 +1,52 @@
+github.com/DATA-DOG/go-sqlmock v1.3.3 h1:CWUqKXe0s8A2z6qCgkP4Kru7wC11YoAnoupUKFDnH08=
+github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/go-gorp/gorp v0.0.0-20160222073440-6a3c8a87d045 h1:3GTkiN2MUTTkojMsGMOhq1epHEorIAPSFOcaFOGnLjo=
+github.com/go-gorp/gorp v0.0.0-20160222073440-6a3c8a87d045/go.mod h1:7IfkAQnO7jfT/9IQ3R9wL1dFhukN6aQxzKTHnkxzA/E=
+github.com/go-gorp/gorp v2.0.0+incompatible h1:dIQPsBtl6/H1MjVseWuWPXa7ET4p6Dve4j3Hg+UjqYw=
+github.com/go-gorp/gorp v2.0.0+incompatible/go.mod h1:7IfkAQnO7jfT/9IQ3R9wL1dFhukN6aQxzKTHnkxzA/E=
+github.com/go-sql-driver/mysql v0.0.0-20160602001021-3654d25ec346/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
+github.com/go-sql-driver/mysql v1.4.1/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
+github.com/golang/protobuf v0.0.0-20160712193813-874264fbbb43/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
+github.com/gopherjs/gopherjs v0.0.0-20190309154008-847fc94819f9/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
+github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
+github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7C0MuV77Wo=
+github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
+github.com/lib/pq v0.0.0-20160623220637-4dd446efc176/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/mattn/go-sqlite3 v0.0.0-20160514122348-38ee283dabf1/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
+github.com/mattn/go-sqlite3 v1.10.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
+github.com/onsi/ginkgo v0.0.0-20160713133600-01a0bc330e32/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/ginkgo v1.8.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/gomega v0.0.0-20160713044445-9574b2d94c03/go.mod h1:C1qb7wdrVGGVU+Z6iS04AVkA3Q65CEZX59MT0QO5uiA=
+github.com/onsi/gomega v1.5.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM=
+github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
+github.com/smartystreets/assertions v0.0.0-20190215210624-980c5ac6f3ac h1:wbW+Bybf9pXxnCFAOWZTqkRjAc7rAIwo2e1ArUhiHxg=
+github.com/smartystreets/assertions v0.0.0-20190215210624-980c5ac6f3ac/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
+github.com/smartystreets/goconvey v0.0.0-20190306220146-200a235640ff h1:86HlEv0yBCry9syNuylzqznKXDK11p6D0DT596yNMys=
+github.com/smartystreets/goconvey v0.0.0-20190306220146-200a235640ff/go.mod h1:KSQcGKpxUMHk3nbYzs/tIBAM2iDooCn0BmttHOJEbLs=
+github.com/ziutek/mymysql v0.0.0-20160623123511-8787d5581eb6/go.mod h1:LMSpPZ6DbqWFxNCHW77HeMg9I646SAhApZ/wKdgO/C0=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190327091125-710a502c58a2/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20160712235641-b518c298ac9d/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190322080309-f49334f85ddc/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20160105164936-4f90aeace3a2/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
+gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
+gopkg.in/yaml.v2 v2.0.0-20160301204022-a83829b6f129/go.mod h1:JAlM8MvJe8wmxCU4Bli9HhUf9+ttbYbLASfIpnQbh74=
+gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

server.go

@@ -20,6 +20,7 @@ type Server struct {
 	connection            *gorp.DbMap
 	replicationConnection *gorp.DbMap
 	traceOn               bool
+	isChecking            bool
 }
 
 // GetName returns server's name
@@ -68,6 +69,16 @@ func (s *Server) connect(dsn string, traceOn bool, logger Logger) (*gorp.DbMap,
 func (s *Server) CheckHealth(traceOn bool, logger Logger) {
 	var secondsBehindMaster, openConnections, runningConnections *int
 
+	// prevent concurrently checks on same server (slow queries/network)
+	if s.isChecking {
+		return
+	}
+
+	s.isChecking = true
+	defer func() {
+		s.isChecking = false
+	}()
+
 	if err := s.connectIfNecessary(traceOn, logger); err != nil {
 		s.health.setDown(
 			err, secondsBehindMaster, openConnections, runningConnections,
@@ -76,28 +87,33 @@ func (s *Server) CheckHealth(traceOn bool, logger Logger) {
 	}
 
 	slaveStatusResult, err := s.rawQuery("SHOW SLAVE STATUS", logger)
-	if err == nil {
-		rawSecondsBehindMaster := strings.TrimSpace(slaveStatusResult["Seconds_Behind_Master"])
-		if rawSecondsBehindMaster == "" || strings.ToLower(rawSecondsBehindMaster) == "null" {
-			s.health.setDown(
-				fmt.Errorf("empty or null value for Seconds_Behind_Master returned from MySQL: %s", err),
-				secondsBehindMaster, openConnections, runningConnections,
-			)
-			return
-		}
+	if err != nil {
+		s.health.setDown(
+			err, secondsBehindMaster, openConnections, runningConnections,
+		)
+		return
+	}
 
-		tmp, err := strconv.Atoi(rawSecondsBehindMaster)
-		if err != nil {
-			s.health.setDown(
-				fmt.Errorf("unexpected value for Seconds_Behind_Master returned from MySQL (conversion error): %s", err),
-				secondsBehindMaster, openConnections, runningConnections,
-			)
-			return
-		}
+	rawSecondsBehindMaster := strings.TrimSpace(slaveStatusResult["Seconds_Behind_Master"])
+	if rawSecondsBehindMaster == "" || strings.ToLower(rawSecondsBehindMaster) == "null" {
+		s.health.setDown(
+			fmt.Errorf("empty or null value for Seconds_Behind_Master returned from MySQL: %s", err),
+			secondsBehindMaster, openConnections, runningConnections,
+		)
+		return
+	}
 
-		secondsBehindMaster = &tmp
+	tmp, err := strconv.Atoi(rawSecondsBehindMaster)
+	if err != nil {
+		s.health.setDown(
+			fmt.Errorf("unexpected value for Seconds_Behind_Master returned from MySQL (conversion error): %s", err),
+			secondsBehindMaster, openConnections, runningConnections,
+		)
+		return
 	}
 
+	secondsBehindMaster = &tmp
+
 	threadsConnectedResult, err := s.rawQuery("SHOW STATUS LIKE 'Threads_connected'", logger)
 	if err != nil {
 		s.health.setDown(

server_test.go

@@ -7,9 +7,9 @@ import (
 	"regexp"
 	"testing"
 
+	sqlmock "github.com/DATA-DOG/go-sqlmock"
 	"github.com/go-gorp/gorp"
 	. "github.com/smartystreets/goconvey/convey"
-	"gopkg.in/DATA-DOG/go-sqlmock.v1"
 )
 
 type LoggerMock struct {