From 583a63a68f66ad4c954aaec42afa0e9ac101a212 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Sun, 24 Dec 2017 15:05:07 +0100
Subject: [PATCH] refactor: encapsulate pulling in a struct

refs #10
---
 cmd/config_job_control.go | 50 +++++++++++++++++++++++++++------------
 cmd/config_job_local.go   |  4 ++--
 cmd/config_job_pull.go    |  4 ++--
 cmd/replication.go        |  4 ++--
 4 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/cmd/config_job_control.go b/cmd/config_job_control.go
index 7328cfb..ba9ff63 100644
--- a/cmd/config_job_control.go
+++ b/cmd/config_job_control.go
@@ -32,17 +32,6 @@ func (j *ControlJob) JobName() string {
 	return j.Name
 }
 
-func (j *ControlJob) EndpointVersion(w http.ResponseWriter, r *http.Request) {
-	var buf bytes.Buffer
-	err := json.NewEncoder(&buf).Encode(NewZreplVersionInformation())
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		io.WriteString(w, err.Error())
-	} else {
-		io.Copy(w, &buf)
-	}
-}
-
 const (
 	ControlJobEndpointProfile string = "/debug/pprof/profile"
 	ControlJobEndpointVersion string = "/version"
@@ -60,8 +49,11 @@ func (j *ControlJob) JobStart(ctx context.Context) {
 	}
 
 	mux := http.NewServeMux()
-	mux.Handle(ControlJobEndpointProfile, requestLogger{log, pprof.Profile})
-	mux.Handle(ControlJobEndpointVersion, requestLogger{log, j.EndpointVersion})
+	mux.Handle(ControlJobEndpointProfile, requestLogger{log: log, handlerFunc: pprof.Profile})
+	mux.Handle(ControlJobEndpointVersion,
+		requestLogger{log: log, handler: jsonResponder{func() (interface{}, error) {
+			return NewZreplVersionInformation(), nil
+		}}})
 	server := http.Server{Handler: mux}
 
 outer:
@@ -89,14 +81,42 @@ outer:
 
 }
 
+type jsonResponder struct {
+	producer func() (interface{}, error)
+}
+
+func (j jsonResponder) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	res, err := j.producer()
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		io.WriteString(w, err.Error())
+		return
+	}
+	var buf bytes.Buffer
+	err = json.NewEncoder(&buf).Encode(res)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		io.WriteString(w, err.Error())
+	} else {
+		io.Copy(w, &buf)
+	}
+}
+
 type requestLogger struct {
 	log         Logger
-	handlerFunc func(w http.ResponseWriter, r *http.Request)
+	handler     http.Handler
+	handlerFunc http.HandlerFunc
 }
 
 func (l requestLogger) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	log := l.log.WithField("method", r.Method).WithField("url", r.URL)
 	log.Info("start")
-	l.handlerFunc(w, r)
+	if l.handlerFunc != nil {
+		l.handlerFunc(w, r)
+	} else if l.handler != nil {
+		l.handler.ServeHTTP(w, r)
+	} else {
+		log.Error("no handler or handlerFunc configured")
+	}
 	log.Info("finish")
 }
diff --git a/cmd/config_job_local.go b/cmd/config_job_local.go
index c6a7f6d..77bd5a1 100644
--- a/cmd/config_job_local.go
+++ b/cmd/config_job_local.go
@@ -137,8 +137,8 @@ outer:
 		{
 			log := pullCtx.Value(contextKeyLog).(Logger)
 			log.Debug("replicating from lhs to rhs")
-			err := doPull(PullContext{local, log, j.Mapping, j.InitialReplPolicy})
-			if err != nil {
+			puller := Puller{local, log, j.Mapping, j.InitialReplPolicy}
+			if err := puller.doPull(); err != nil {
 				log.WithError(err).Error("error replicating lhs to rhs")
 			}
 			// use a ctx as soon as doPull gains ctx support
diff --git a/cmd/config_job_pull.go b/cmd/config_job_pull.go
index e34f13c..0fb1a2b 100644
--- a/cmd/config_job_pull.go
+++ b/cmd/config_job_pull.go
@@ -120,8 +120,8 @@ start:
 	log.Info("starting pull")
 
 	pullLog := log.WithField(logTaskField, "pull")
-	err = doPull(PullContext{client, pullLog, j.Mapping, j.InitialReplPolicy})
-	if err != nil {
+	puller := Puller{client, pullLog, j.Mapping, j.InitialReplPolicy}
+	if err = puller.doPull(); err != nil {
 		log.WithError(err).Error("error doing pull")
 	}
 
diff --git a/cmd/replication.go b/cmd/replication.go
index 9cd34e1..407415f 100644
--- a/cmd/replication.go
+++ b/cmd/replication.go
@@ -52,14 +52,14 @@ func closeRPCWithTimeout(log Logger, remote rpc.RPCClient, timeout time.Duration
 	return
 }
 
-type PullContext struct {
+type Puller struct {
 	Remote            rpc.RPCClient
 	Log               Logger
 	Mapping           DatasetMapping
 	InitialReplPolicy InitialReplPolicy
 }
 
-func doPull(pull PullContext) (err error) {
+func (pull *Puller) doPull() (err error) {
 
 	remote := pull.Remote
 	log := pull.Log