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Pass in custom metrics list
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The idea is that a user can pass in a list of metric structs, and
metrics will be appropriated for them based on the metric type.
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Brian Richardson committed Feb 12, 2018
1 parent e26effb commit 8b8a954
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Showing 2 changed files with 178 additions and 59 deletions.
23 changes: 22 additions & 1 deletion example/example.go
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Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,30 @@ import (
func main() {
r := gin.New()

/* // Optional custom metrics list
customMetrics := []*ginprometheus.Metric{
&ginprometheus.Metric{
ID: "1234", // optional string
Name: "test_metric", // required string
Description: "Counter test metric", // required string
Type: "counter", // required string
},
&ginprometheus.Metric{
ID: "1235", // Identifier
Name: "test_metric_2", // Metric Name
Description: "Summary test metric", // Help Description
Type: "summary", // type associated with prometheus collector
},
// Type Options:
// counter, counter_vec, gauge, gauge_vec,
// histogram, histogram_vec, summary, summary_vec
}
p := ginprometheus.NewPrometheus("gin", customMetrics)
*/

p := ginprometheus.NewPrometheus("gin")
p.Use(r)

p.Use(r)
r.GET("/", func(c *gin.Context) {
c.JSON(200, "Hello world!")
})
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214 changes: 156 additions & 58 deletions middleware.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,41 @@ import (

var defaultMetricPath = "/metrics"

// Standard default metrics
// counter, counter_vec, gauge, gauge_vec,
// histogram, histogram_vec, summary, summary_vec
var reqCnt = &Metric{
ID: "reqCnt",
Name: "requests_total",
Description: "How many HTTP requests processed, partitioned by status code and HTTP method.",
Type: "counter_vec",
Args: []string{"code", "method", "handler", "host", "url"}}

var reqDur = &Metric{
ID: "reqDur",
Name: "request_duration_seconds",
Description: "The HTTP request latencies in seconds.",
Type: "summary"}

var resSz = &Metric{
ID: "resSz",
Name: "response_size_bytes",
Description: "The HTTP response sizes in bytes.",
Type: "summary"}

var reqSz = &Metric{
ID: "reqSz",
Name: "request_size_bytes",
Description: "The HTTP request sizes in bytes.",
Type: "summary"}

var standardMetrics = []*Metric{
reqCnt,
reqDur,
resSz,
reqSz,
}

/*
RequestCounterURLLabelMappingFn is a function which can be supplied to the middleware to control
the cardinality of the request counter's "url" label, which might be required in some contexts.
Expand All @@ -37,15 +72,26 @@ which would map "/customer/alice" and "/customer/bob" to their template "/custom
*/
type RequestCounterURLLabelMappingFn func(c *gin.Context) string

// Metric is a definition for the name, description, type, ID, and
// prometheus.Collector type (i.e. CounterVec, Summary, etc) of each metric
type Metric struct {
MetricCollector prometheus.Collector
ID string
Name string
Description string
Type string
Args []string
}

// Prometheus contains the metrics gathered by the instance and its path
type Prometheus struct {
reqCnt *prometheus.CounterVec
reqDur, reqSz, resSz prometheus.Summary
router *gin.Engine
listenAddress string
Ppg PrometheusPushGateway

Ppg PrometheusPushGateway

MetricsList []*Metric
MetricsPath string

ReqCntURLLabelMappingFn RequestCounterURLLabelMappingFn
Expand All @@ -70,14 +116,28 @@ type PrometheusPushGateway struct {
}

// NewPrometheus generates a new set of metrics with a certain subsystem name
func NewPrometheus(subsystem string) *Prometheus {
func NewPrometheus(subsystem string, customMetricsList ...[]*Metric) *Prometheus {

var metricsList []*Metric

if len(customMetricsList) > 1 {
panic("Too many args. NewPrometheus( string, <optional []*Metric> ).")
} else if len(customMetricsList) == 1 {
metricsList = customMetricsList[0]
}

for _, metric := range standardMetrics {
metricsList = append(metricsList, metric)
}

p := &Prometheus{
MetricsList: metricsList,
MetricsPath: defaultMetricPath,
ReqCntURLLabelMappingFn: func(c *gin.Context) string {
return c.Request.URL.String() // i.e. by default do nothing, i.e. return URL as is
},
}

p.registerMetrics(subsystem)

return p
Expand Down Expand Up @@ -168,65 +228,103 @@ func (p *Prometheus) startPushTicker() {
}()
}

func (p *Prometheus) registerMetrics(subsystem string) {

p.reqCnt = prometheus.NewCounterVec(
prometheus.CounterOpts{
Subsystem: subsystem,
Name: "requests_total",
Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
},
[]string{"code", "method", "handler", "host", "url"},
)

if err := prometheus.Register(p.reqCnt); err != nil {
log.Info("reqCnt could not be registered: ", err)
} else {
log.Info("reqCnt registered.")
}

p.reqDur = prometheus.NewSummary(
prometheus.SummaryOpts{
Subsystem: subsystem,
Name: "request_duration_seconds",
Help: "The HTTP request latencies in seconds.",
},
)

if err := prometheus.Register(p.reqDur); err != nil {
log.Info("reqDur could not be registered: ", err)
} else {
log.Info("reqDur registered.")
}

p.reqSz = prometheus.NewSummary(
prometheus.SummaryOpts{
Subsystem: subsystem,
Name: "request_size_bytes",
Help: "The HTTP request sizes in bytes.",
},
)

if err := prometheus.Register(p.reqSz); err != nil {
log.Info("reqSz could not be registered: ", err)
} else {
log.Info("reqSz registered.")
// NewMetric associates prometheus.Collector based on Metric.Type
func NewMetric(m *Metric, subsystem string) prometheus.Collector {
var metric prometheus.Collector
switch m.Type {
case "counter_vec":
metric = prometheus.NewCounterVec(
prometheus.CounterOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
m.Args,
)
case "counter":
metric = prometheus.NewCounter(
prometheus.CounterOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
)
case "gauge_vec":
metric = prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
m.Args,
)
case "gauge":
metric = prometheus.NewGauge(
prometheus.GaugeOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
)
case "histogram_vec":
metric = prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
m.Args,
)
case "histogram":
metric = prometheus.NewHistogram(
prometheus.HistogramOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
)
case "summary_vec":
metric = prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
m.Args,
)
case "summary":
metric = prometheus.NewSummary(
prometheus.SummaryOpts{
Subsystem: subsystem,
Name: m.Name,
Help: m.Description,
},
)
}
return metric
}

p.resSz = prometheus.NewSummary(
prometheus.SummaryOpts{
Subsystem: subsystem,
Name: "response_size_bytes",
Help: "The HTTP response sizes in bytes.",
},
)
func (p *Prometheus) registerMetrics(subsystem string) {

if err := prometheus.Register(p.resSz); err != nil {
log.Info("resSz could not be registered: ", err)
} else {
log.Info("resSz registered.")
for _, metricDef := range p.MetricsList {
metric := NewMetric(metricDef, subsystem)
if err := prometheus.Register(metric); err != nil {
log.Infof("%s could not be registered: ", metricDef.Name, err)
} else {
log.Infof("%s registered.", metricDef.Name)
}
switch metricDef {
case reqCnt:
p.reqCnt = metric.(*prometheus.CounterVec)
case reqDur:
p.reqDur = metric.(prometheus.Summary)
case resSz:
p.resSz = metric.(prometheus.Summary)
case reqSz:
p.reqSz = metric.(prometheus.Summary)
}
metricDef.MetricCollector = metric
}

}

// Use adds the middleware to a gin engine.
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