From 624e57d292e653969c0941c86729b7ad1a4274d1 Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" <matt.proud@gmail.com>
Date: Sun, 21 Jul 2013 17:09:48 +0200
Subject: [PATCH 1/3] Enclose artifact generation process into Makefile.

Completely decouple the build process from Travis and other things we
cannot control.
---
 .gitignore                  |  1 +
 .travis.yml                 |  2 +-
 Makefile                    | 55 +++++++++++++++++++++++++++++++++----
 Makefile.TRAVIS             | 31 ---------------------
 examples/delegator/Makefile |  6 ++--
 examples/random/Makefile    |  6 ++--
 examples/simple/Makefile    |  6 ++--
 prometheus/Makefile         | 13 +++++----
 8 files changed, 69 insertions(+), 51 deletions(-)
 delete mode 100644 Makefile.TRAVIS

diff --git a/.gitignore b/.gitignore
index 4482aca..f6fc2e8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,3 +23,4 @@ _testmain.go
 
 *~
 *#
+.build
diff --git a/.travis.yml b/.travis.yml
index 2c7ccd3..afeb72d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,4 +4,4 @@ go:
  - 1.1
 
 script:
- - make -f Makefile.TRAVIS
+ - make -f Makefile
diff --git a/Makefile b/Makefile
index c43f4c3..3ba28b1 100644
--- a/Makefile
+++ b/Makefile
@@ -11,14 +11,53 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-MAKE_ARTIFACTS = search_index
+OS   = $(shell uname)
+ARCH = $(shell uname -m)
+
+BUILD_PATH = $(PWD)/.build
+
+export GO_VERSION = 1.1
+export GOOS 	    = $(subst Darwin,darwin,$(subst Linux,linux,$(OS)))
+export GOARCH		  = $(subst x86_64,amd64,$(ARCH))
+export GOPKG		  = go$(GO_VERSION).$(GOOS)-$(GOARCH).tar.gz
+export GOROOT		  = $(BUILD_PATH)/root/go
+export GOPATH		  = $(BUILD_PATH)/root/gopath
+export GOCC		    = $(GOROOT)/bin/go
+export TMPDIR		  = /tmp
+export GOENV		  = TMPDIR=$(TMPDIR) GOROOT=$(GOROOT) GOPATH=$(GOPATH)
+export GO	        = $(GOENV) $(GOCC)
+export GOFMT		  = $(GOROOT)/bin/gofmt
+
+FULL_GOPATH = $(GOPATH)/src/github.com/prometheus/client_golang
+FULL_GOPATH_BASE = $(GOPATH)/src/github.com/prometheus
+
+MAKE_ARTIFACTS = search_index $(BUILD_PATH)
 
 all: test
 
-build:
+$(BUILD_PATH):
+	mkdir -vp $(BUILD_PATH)
+
+$(BUILD_PATH)/cache: $(BUILD_PATH)
+	mkdir -vp $(BUILD_PATH)/cache
+
+$(BUILD_PATH)/root: $(BUILD_PATH)
+	mkdir -vp $(BUILD_PATH)/root
+
+$(BUILD_PATH)/cache/$(GOPKG): $(BUILD_PATH)/cache
+	curl -o $@ http://go.googlecode.com/files/$(GOPKG)
+
+$(GOCC): $(BUILD_PATH)/root $(BUILD_PATH)/cache/$(GOPKG)
+	tar -C $(BUILD_PATH)/root -xzf $(BUILD_PATH)/cache/$(GOPKG)
+	touch $@
+
+build: source_path dependencies
 	$(MAKE) -C prometheus build
 	$(MAKE) -C examples build
 
+dependencies: source_path $(GOCC)
+	$(GO) get github.com/matttproud/gocheck
+
 test: build
 	$(MAKE) -C prometheus test
 	$(MAKE) -C examples test
@@ -28,18 +67,24 @@ advice: test
 	$(MAKE) -C examples advice
 
 format:
-	find . -iname '*.go' -exec gofmt -w -s=true '{}' ';'
+	find . -iname '*.go' | grep -v './.build/' | xargs -n1 -P1 $(GOFMT) -w -s=true
 
 search_index:
 	godoc -index -write_index -index_files='search_index'
 
+# source_path is responsible for ensuring that the builder has not done anything
+# stupid like working on Prometheus outside of ${GOPATH}.
+source_path:
+	-[ -d "$(FULL_GOPATH)" ] || { mkdir -vp $(FULL_GOPATH_BASE) ; ln -s "$(PWD)" "$(FULL_GOPATH)" ; }
+	[ -d "$(FULL_GOPATH)" ]
+
 documentation: search_index
 	godoc -http=:6060 -index -index_files='search_index'
 
 clean:
 	$(MAKE) -C examples clean
-	rm -f $(MAKE_ARTIFACTS)
+	rm -rf $(MAKE_ARTIFACTS)
 	find . -iname '*~' -exec rm -f '{}' ';'
 	find . -iname '*#' -exec rm -f '{}' ';'
 
-.PHONY: advice build clean documentation format test
+.PHONY: advice build clean documentation format source_path test
diff --git a/Makefile.TRAVIS b/Makefile.TRAVIS
deleted file mode 100644
index 9a6b35b..0000000
--- a/Makefile.TRAVIS
+++ /dev/null
@@ -1,31 +0,0 @@
-# Copyright 2013 Prometheus Team
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-PROMETHEUS_TARGET := "${GOPATH}/src/github.com/prometheus"
-
-all: test
-
-preparation:
-	mkdir -vp $(PROMETHEUS_TARGET)
-	ln -sf "$(PWD)" $(PROMETHEUS_TARGET)
-
-dependencies:
-	go get code.google.com/p/goprotobuf/proto
-	go get github.com/matttproud/gocheck
-	go get github.com/matttproud/golang_protobuf_extensions/ext
-	go get github.com/prometheus/client_model/go
-
-test: dependencies preparation
-	$(MAKE) test
-
-.PHONY: dependencies preparation test
diff --git a/examples/delegator/Makefile b/examples/delegator/Makefile
index c60b94c..2d8ef05 100644
--- a/examples/delegator/Makefile
+++ b/examples/delegator/Makefile
@@ -18,13 +18,13 @@ all: test
 build: delegator
 
 delegator:
-	go build .
+	$(GO) build .
 
 test: build
-	go test . $(GO_TEST_FLAGS)
+	$(GO) test . $(GO_TEST_FLAGS)
 
 advice:
-	go tool vet .
+	$(GO) tool vet .
 
 clean:
 	rm -f $(MAKE_ARTIFACTS)
diff --git a/examples/random/Makefile b/examples/random/Makefile
index c54b305..0d5e48a 100644
--- a/examples/random/Makefile
+++ b/examples/random/Makefile
@@ -18,13 +18,13 @@ all: test
 build: random
 
 random:
-	go build .
+	$(GO) build .
 
 test: build
-	go test . $(GO_TEST_FLAGS)
+	$(GO) test . $(GO_TEST_FLAGS)
 
 advice:
-	go tool vet .
+	$(GO) tool vet .
 
 clean:
 	rm -f $(MAKE_ARTIFACTS)
diff --git a/examples/simple/Makefile b/examples/simple/Makefile
index dba8a98..88526d3 100644
--- a/examples/simple/Makefile
+++ b/examples/simple/Makefile
@@ -18,13 +18,13 @@ all: test
 build: simple
 
 simple:
-	go build .
+	$(GO) build .
 
 test: build
-	go test . $(GO_TEST_FLAGS)
+	$(GO) test . $(GO_TEST_FLAGS)
 
 advice:
-	go tool vet .
+	$(GO) tool vet .
 
 clean:
 	rm -f $(MAKE_ARTIFACTS)
diff --git a/prometheus/Makefile b/prometheus/Makefile
index 85b7b46..4c1e51d 100644
--- a/prometheus/Makefile
+++ b/prometheus/Makefile
@@ -13,13 +13,16 @@
 
 all: test
 
-build:
-	go build ./...
+build: dependencies
+	$(GO) build ./...
+
+dependencies: $(GOCC)
+	$(GO) get -d
 
 test: build
-	go test ./... $(GO_TEST_FLAGS)
+	$(GO) test ./... $(GO_TEST_FLAGS)
 
 advice:
-	go tool vet .
+	$(GO) tool vet .
 
-.PHONY: advice build test
+.PHONY: advice build dependencies test

From a10d055c32ec3ef50b9d1b921975f71b948515bb Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" <matt.proud@gmail.com>
Date: Sun, 21 Jul 2013 17:14:29 +0200
Subject: [PATCH 2/3] Include sample count and sum in Proto output.

---
 prometheus/histogram.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/prometheus/histogram.go b/prometheus/histogram.go
index 85389a2..5a806bb 100644
--- a/prometheus/histogram.go
+++ b/prometheus/histogram.go
@@ -87,6 +87,8 @@ type histogram struct {
 type histogramVector struct {
 	buckets []Bucket
 	labels  map[string]string
+	sum     float64
+	count   uint64
 }
 
 func (h *histogram) Add(labels map[string]string, value float64) {
@@ -124,6 +126,9 @@ func (h *histogram) Add(labels map[string]string, value float64) {
 	}
 
 	histogram.buckets[lastIndex].Add(value)
+
+	histogram.sum += value
+	histogram.count++
 }
 
 func (h *histogram) String() string {
@@ -313,7 +318,10 @@ func (metric *histogram) dumpChildren(f *dto.MetricFamily) {
 	f.Type = dto.MetricType_SUMMARY.Enum()
 
 	for signature, child := range metric.values {
-		c := &dto.Summary{}
+		c := &dto.Summary{
+			SampleSum:   proto.Float64(child.sum),
+			SampleCount: proto.Uint64(child.count),
+		}
 
 		m := &dto.Metric{
 			Summary: c,

From 93130ba5c3bd52e920b7709c12c2a9a7cfb4af70 Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" <matt.proud@gmail.com>
Date: Sun, 21 Jul 2013 17:34:37 +0200
Subject: [PATCH 3/3] Introduce histogram purging support.

---
 prometheus/histogram.go | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/prometheus/histogram.go b/prometheus/histogram.go
index 5a806bb..3d5f9e7 100644
--- a/prometheus/histogram.go
+++ b/prometheus/histogram.go
@@ -13,6 +13,7 @@ import (
 	"math"
 	"strconv"
 	"sync"
+	"time"
 
 	dto "github.com/prometheus/client_model/go"
 
@@ -54,6 +55,7 @@ type HistogramSpecification struct {
 	BucketBuilder         BucketBuilder
 	ReportablePercentiles []float64
 	Starts                []float64
+	PurgeInterval         time.Duration
 }
 
 type Histogram interface {
@@ -82,6 +84,9 @@ type histogram struct {
 	values map[uint64]*histogramVector
 	// These are the percentile values that will be reported on marshalling.
 	reportablePercentiles []float64
+
+	purgeInterval time.Duration
+	lastPurge     time.Time
 }
 
 type histogramVector struct {
@@ -249,6 +254,8 @@ func formatFloat(value float64) string {
 }
 
 func (h *histogram) MarshalJSON() ([]byte, error) {
+	h.Purge()
+
 	h.mutex.RLock()
 	defer h.mutex.RUnlock()
 
@@ -274,10 +281,29 @@ func (h *histogram) MarshalJSON() ([]byte, error) {
 	})
 }
 
+func (h *histogram) Purge() {
+	if h.purgeInterval == 0 {
+		return
+	}
+
+	h.mutex.Lock()
+	defer h.mutex.Unlock()
+	if time.Since(h.lastPurge) < h.purgeInterval {
+		return
+	}
+
+	h.resetAll()
+	h.lastPurge = time.Now()
+}
+
 func (h *histogram) ResetAll() {
 	h.mutex.Lock()
 	defer h.mutex.Unlock()
 
+	h.resetAll()
+}
+
+func (h *histogram) resetAll() {
 	for signature, value := range h.values {
 		for _, bucket := range value.buckets {
 			bucket.Reset()
@@ -294,6 +320,8 @@ func NewHistogram(specification *HistogramSpecification) Histogram {
 		bucketStarts:          specification.Starts,
 		reportablePercentiles: specification.ReportablePercentiles,
 		values:                map[uint64]*histogramVector{},
+		lastPurge:             time.Now(),
+		purgeInterval:         specification.PurgeInterval,
 	}
 
 	return metric
@@ -307,11 +335,14 @@ func NewDefaultHistogram() Histogram {
 			Starts:                LogarithmicSizedBucketsFor(0, 4096),
 			BucketBuilder:         AccumulatingBucketBuilder(EvictAndReplaceWith(10, AverageReducer), 50),
 			ReportablePercentiles: []float64{0.01, 0.05, 0.5, 0.90, 0.99},
+			PurgeInterval:         15 * time.Minute,
 		},
 	)
 }
 
 func (metric *histogram) dumpChildren(f *dto.MetricFamily) {
+	metric.Purge()
+
 	metric.mutex.RLock()
 	defer metric.mutex.RUnlock()