From 0d5e5a2fbede19338e77d2d5e903dfe927d4d2ce Mon Sep 17 00:00:00 2001
From: Anton Novojilov <andy@essentialkaos.com>
Date: Wed, 23 Dec 2015 00:04:35 +0100
Subject: [PATCH] Added collector feature + Added changelog

---
 changelog.md | 10 +++++++
 librato.go   | 80 ++++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 81 insertions(+), 9 deletions(-)
 create mode 100644 changelog.md

diff --git a/changelog.md b/changelog.md
new file mode 100644
index 0000000..7029f5d
--- /dev/null
+++ b/changelog.md
@@ -0,0 +1,10 @@
+## Changelog
+
+#### v1.1
+
+* Added `Collector` for collecting metrics for some period
+* Some minor improvements
+
+#### v1
+
+Initial public release
diff --git a/librato.go b/librato.go
index b91b7af..74283d4 100644
--- a/librato.go
+++ b/librato.go
@@ -22,7 +22,8 @@ import (
 
 // ////////////////////////////////////////////////////////////////////////////////// //
 
-const VERSION = "1.0"
+// VERSION contains current version of librato package and used as part of User-Agent
+const VERSION = "1.1"
 
 // ////////////////////////////////////////////////////////////////////////////////// //
 
@@ -54,6 +55,16 @@ type Metrics struct {
 	ErrorHandler func(errs []error)
 }
 
+// Collector struct
+type Collector struct {
+	period          time.Duration
+	lastSendingDate int64
+	collectFunc     func() []Measurement
+
+	// Function executed if we have errors while sending data to Librato
+	ErrorHandler func(errs []error)
+}
+
 // Gauge struct
 type Gauge struct {
 
@@ -251,6 +262,24 @@ func NewMetrics(period time.Duration, maxQueueSize int) (*Metrics, error) {
 	return metrics, nil
 }
 
+// NewCollector create new metrics struct for async metrics collecting and sending
+func NewCollector(period time.Duration, collectFunc func() []Measurement) *Collector {
+	collector := &Collector{
+		period:          period,
+		lastSendingDate: -1,
+		collectFunc:     collectFunc,
+	}
+
+	if sources == nil {
+		sources = make([]DataSource, 0)
+		go sendingLoop()
+	}
+
+	sources = append(sources, collector)
+
+	return collector
+}
+
 // AddMetric synchronously send metric to librato
 func AddMetric(m Measurement) []error {
 	err := m.Validate()
@@ -343,7 +372,30 @@ func (mt *Metrics) Send() []error {
 
 	mt.lastSendingDate = time.Now().Unix()
 
-	return mt.sendData()
+	data := convertMeasurementSlice(mt.queue)
+
+	mt.queue = make([]Measurement, 0)
+
+	return execRequest(req.POST, APIEndpoint+"/v1/metrics/", data)
+}
+
+// Send sends metrics data to Librato service
+func (cl *Collector) Send() []error {
+	if Mail == "" || Token == "" {
+		return []error{errors.New("Access credentials is not set")}
+	}
+
+	ms := cl.collectFunc()
+
+	if ms == nil || len(ms) == 0 {
+		return []error{}
+	}
+
+	cl.lastSendingDate = time.Now().Unix()
+
+	data := convertMeasurementSlice(ms)
+
+	return execRequest(req.POST, APIEndpoint+"/v1/metrics/", data)
 }
 
 // ////////////////////////////////////////////////////////////////////////////////// //
@@ -379,13 +431,23 @@ func (mt *Metrics) execErrorHandler(errs []error) {
 	mt.ErrorHandler(errs)
 }
 
-// sendData send json encoded metrics data to Librato service
-func (mt *Metrics) sendData() []error {
-	data := convertQueue(mt.queue)
+// getPeriod return sending period
+func (cl *Collector) getPeriod() time.Duration {
+	return cl.period
+}
 
-	mt.queue = make([]Measurement, 0)
+// getLastSendingDate return last sending date
+func (cl *Collector) getLastSendingDate() int64 {
+	return cl.lastSendingDate
+}
 
-	return execRequest(req.POST, APIEndpoint+"/v1/metrics/", data)
+// execErrorHandler exec error handler if present
+func (cl *Collector) execErrorHandler(errs []error) {
+	if cl.ErrorHandler == nil {
+		return
+	}
+
+	cl.ErrorHandler(errs)
 }
 
 // ////////////////////////////////////////////////////////////////////////////////// //
@@ -428,9 +490,9 @@ func sendingLoop() {
 	}
 }
 
-// convertQueue convert slice with measurements to struct
+// convertMeasurementSlice convert slice with measurements to struct
 // with counters and gauges slices
-func convertQueue(queue []Measurement) *mesData {
+func convertMeasurementSlice(queue []Measurement) *mesData {
 	result := &mesData{}
 
 	now := time.Now().Unix()