From b2df1c375afc44c39cfb16833da906ad966a939a Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" <matt.proud@gmail.com>
Date: Fri, 25 Jan 2013 13:45:21 +0100
Subject: [PATCH] A few parameterizations.

---
 main.go             | 14 +++++++++-----
 retrieval/target.go |  6 ++++--
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/main.go b/main.go
index d57f228149..3cdd142ba4 100644
--- a/main.go
+++ b/main.go
@@ -32,8 +32,11 @@ import (
 
 // Commandline flags.
 var (
-	configFile         = flag.String("configFile", "prometheus.conf", "Prometheus configuration file name.")
-	metricsStoragePath = flag.String("metricsStoragePath", "/tmp/metrics", "Base path for metrics storage.")
+	configFile                   = flag.String("configFile", "prometheus.conf", "Prometheus configuration file name.")
+	metricsStoragePath           = flag.String("metricsStoragePath", "/tmp/metrics", "Base path for metrics storage.")
+	scrapeResultsQueueCapacity   = flag.Int("scrapeResultsQueueCapacity", 4096, "The size of the scrape results queue.")
+	ruleResultsQueueCapacity     = flag.Int("ruleResultsQueueCapacity", 4096, "The size of the rule results queue.")
+	concurrentRetrievalAllowance = flag.Int("concurrentRetrievalAllowance", 15, "The number of concurrent metrics retrieval requests allowed.")
 )
 
 func main() {
@@ -59,12 +62,13 @@ func main() {
 
 	defer persistence.Close()
 
-	scrapeResults := make(chan format.Result, 4096)
+	// Queue depth will need to be exposed
+	scrapeResults := make(chan format.Result, *scrapeResultsQueueCapacity)
 
-	targetManager := retrieval.NewTargetManager(scrapeResults, 1)
+	targetManager := retrieval.NewTargetManager(scrapeResults, *concurrentRetrievalAllowance)
 	targetManager.AddTargetsFromConfig(conf)
 
-	ruleResults := make(chan *rules.Result, 4096)
+	ruleResults := make(chan *rules.Result, *ruleResultsQueueCapacity)
 
 	ast.SetPersistence(persistence, nil)
 	ruleManager := rules.NewRuleManager(ruleResults, conf.Global.EvaluationInterval)
diff --git a/retrieval/target.go b/retrieval/target.go
index 660e06506a..f6fbe1ff21 100644
--- a/retrieval/target.go
+++ b/retrieval/target.go
@@ -134,6 +134,10 @@ func (t *target) Scrape(earliest time.Time, results chan format.Result) (err err
 	done := make(chan bool)
 
 	request := func() {
+		defer func() {
+			done <- true
+		}()
+
 		resp, err := http.Get(t.Address())
 		if err != nil {
 			return
@@ -157,8 +161,6 @@ func (t *target) Scrape(earliest time.Time, results chan format.Result) (err err
 		if err != nil {
 			return
 		}
-
-		done <- true
 	}
 
 	accumulator := func(d time.Duration) {