Rename Deliver into Gather

Author: beorn7

prometheus/doc.go

@@ -146,7 +146,7 @@
 // So far, everything we did operated on the so-called default registry, as it
 // can be found in the global DefaultRegistry variable. With NewRegistry, you
 // can create a custom registry, or you can even implement the Registerer or
-// Deliverer interfaces yourself. The methods Register and Unregister work in
+// Gatherer interfaces yourself. The methods Register and Unregister work in
 // the same way on a custom registry as the global functions Register and
 // Unregister on the default registry.
 //
@@ -163,10 +163,10 @@
 //
 // HTTP Exposition
 //
-// The Registry implements the Deliverer interface. The caller of the Deliver
-// method can then expose the delivered metrics in some way. Usually, the
-// metrics are served via HTTP on the /metrics endpoint. That's happening in the
-// example above. The tools to expose metrics via HTTP are in the promhttp
+// The Registry implements the Gatherer interface. The caller of the Gather
+// method can then expose the gathered metrics in some way. Usually, the metrics
+// are served via HTTP on the /metrics endpoint. That's happening in the example
+// above. The tools to expose metrics via HTTP are in the promhttp
 // sub-package. (The top-level functions in the prometheus package are
 // deprecated.)
 //

prometheus/examples_test.go

@@ -390,7 +390,7 @@ func ExampleSummaryVec() {
 	reg := prometheus.NewRegistry()
 	reg.MustRegister(temps)
 
-	metricFamilies, err := reg.Deliver()
+	metricFamilies, err := reg.Gather()
 	if err != nil || len(metricFamilies) != 1 {
 		panic("unexpected behavior of custom test registry")
 	}

prometheus/http.go

@@ -56,7 +56,7 @@ func giveBuf(buf *bytes.Buffer) {
 	bufPool.Put(buf)
 }
 
-// Handler returns an HTTP handler for the DefaultDeliverer. It is
+// Handler returns an HTTP handler for the DefaultGatherer. It is
 // already instrumented with InstrumentHandler (using "prometheus" as handler
 // name).
 //
@@ -67,12 +67,12 @@ func Handler() http.Handler {
 	return InstrumentHandler("prometheus", UninstrumentedHandler())
 }
 
-// UninstrumentedHandler returns an HTTP handler for the DefaultDeliverer.
+// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
 //
 // Deprecated: Use promhttp.Handler instead. See there for further documentation.
 func UninstrumentedHandler() http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		mfs, err := DefaultDeliverer.Deliver()
+		mfs, err := DefaultGatherer.Gather()
 		if err != nil {
 			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
 			return

prometheus/process_collector_test.go

@@ -25,7 +25,7 @@ func TestProcessCollector(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	mfs, err := registry.Deliver()
+	mfs, err := registry.Gather()
 	if err != nil {
 		t.Fatal(err)
 	}

prometheus/promhttp/http.go

@@ -22,9 +22,9 @@
 // will also contain tooling to instrument instances of http.Handler and
 // http.RoundTripper.
 //
-// promhttp.Handler acts on the prometheus.DefaultDeliverer. With HandlerFor,
+// promhttp.Handler acts on the prometheus.DefaultGatherer. With HandlerFor,
 // you can create a handler for a custom registry or anything that implements
-// the Deliverer interface. It also allows to create handlers that act
+// the Gatherer interface. It also allows to create handlers that act
 // differently on errors or allow to log errors.
 package promhttp
 
@@ -64,22 +64,22 @@ func giveBuf(buf *bytes.Buffer) {
 	bufPool.Put(buf)
 }
 
-// Handler returns an HTTP handler for the prometheus.DefaultDeliverer. The
+// Handler returns an HTTP handler for the prometheus.DefaultGatherer. The
 // Handler uses the default HandlerOpts, i.e. report the first error as an HTTP
 // error, no error logging, and compression if requested by the client.
 //
-// If you want to create a Handler for the DefaultDeliverer with different
-// HandlerOpts, create it with HandlerFor with prometheus.DefaultDeliverer and
+// If you want to create a Handler for the DefaultGatherer with different
+// HandlerOpts, create it with HandlerFor with prometheus.DefaultGatherer and
 // your desired HandlerOpts.
 func Handler() http.Handler {
-	return HandlerFor(prometheus.DefaultDeliverer, HandlerOpts{})
+	return HandlerFor(prometheus.DefaultGatherer, HandlerOpts{})
 }
 
-// HandlerFor returns an http.Handler for the provided Deliverer. The behavior
+// HandlerFor returns an http.Handler for the provided Gatherer. The behavior
 // ef the Handler is defined by the provided HandlerOpts.
-func HandlerFor(reg prometheus.Deliverer, opts HandlerOpts) http.Handler {
+func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		mfs, err := reg.Deliver()
+		mfs, err := reg.Gather()
 		if err != nil {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error collecting metrics:", err)

prometheus/push/push.go

@@ -44,9 +44,9 @@ import (
 
 const contentTypeHeader = "Content-Type"
 
-// Registry triggers a metric collection by the provided Deliverer (which is
+// Registry triggers a metric collection by the provided Gatherer (which is
 // usually implemented by a prometheus.Registry, thus the name of the function)
-// and pushes all delivered metrics to the Pushgateway specified by url, using
+// and pushes all gathered metrics to the Pushgateway specified by url, using
 // the provided job name and the (optional) further grouping labels (the
 // grouping map may be nil). See the Pushgateway documentation for detailed
 // implications of the job and other grouping labels. Neither the job name nor
@@ -60,18 +60,18 @@ const contentTypeHeader = "Content-Type"
 // Note that all previously pushed metrics with the same job and other grouping
 // labels will be replaced with the metrics pushed by this call. (It uses HTTP
 // method 'PUT' to push to the Pushgateway.)
-func Registry(job string, grouping map[string]string, url string, reg prometheus.Deliverer) error {
+func Registry(job string, grouping map[string]string, url string, reg prometheus.Gatherer) error {
 	return push(job, grouping, url, reg, "PUT")
 }
 
 // RegistryAdd works like Registry, but only previously pushed metrics with the
 // same name (and the same job and other grouping labels) will be replaced. (It
 // uses HTTP method 'POST' to push to the Pushgateway.)
-func RegistryAdd(job string, grouping map[string]string, url string, reg prometheus.Deliverer) error {
+func RegistryAdd(job string, grouping map[string]string, url string, reg prometheus.Gatherer) error {
 	return push(job, grouping, url, reg, "POST")
 }
 
-func push(job string, grouping map[string]string, pushURL string, reg prometheus.Deliverer, method string) error {
+func push(job string, grouping map[string]string, pushURL string, reg prometheus.Gatherer, method string) error {
 	if !strings.Contains(pushURL, "://") {
 		pushURL = "http://" + pushURL
 	}
@@ -94,7 +94,7 @@ func push(job string, grouping map[string]string, pushURL string, reg prometheus
 	}
 	pushURL = fmt.Sprintf("%s/metrics/job/%s", pushURL, strings.Join(urlComponents, "/"))
 
-	mfs, err := reg.Deliver()
+	mfs, err := reg.Gather()
 	if err != nil {
 		return err
 	}
@@ -134,14 +134,14 @@ func push(job string, grouping map[string]string, pushURL string, reg prometheus
 	return nil
 }
 
-// Collectors works like Registry, but it does not use a Deliverer. Instead, it
+// Collectors works like Registry, but it does not use a Gatherer. Instead, it
 // collects from the provided collectors directly. It is a convenient way to
 // push only a few metrics.
 func Collectors(job string, grouping map[string]string, url string, collectors ...prometheus.Collector) error {
 	return pushCollectors(job, grouping, url, "PUT", collectors...)
 }
 
-// AddCollectors works like RegistryAdd, but it does not use a Deliverer.
+// AddCollectors works like RegistryAdd, but it does not use a Gatherer.
 // Instead, it collects from the provided collectors directly. It is a
 // convenient way to push only a few metrics.
 func AddCollectors(job string, grouping map[string]string, url string, collectors ...prometheus.Collector) error {

prometheus/push/push_test.go

@@ -83,7 +83,7 @@ func TestPush(t *testing.T) {
 	reg.MustRegister(metric1)
 	reg.MustRegister(metric2)
 
-	mfs, err := reg.Deliver()
+	mfs, err := reg.Gather()
 	if err != nil {
 		t.Fatal(err)
 	}

prometheus/registry.go

@@ -33,7 +33,7 @@ const (
 )
 
 // DefaultRegistry is a Registry instance that has a ProcessCollector and a
-// GoCollector pre-registered. DefaultRegisterer and DefaultDeliverer are both
+// GoCollector pre-registered. DefaultRegisterer and DefaultGatherer are both
 // pointing to it. A number of convenience functions in this package act on
 // them. This approach to keep a default instance as global state mirrors the
 // approach of other packages in the Go standard library. Note that there are
@@ -43,7 +43,7 @@ const (
 var (
 	DefaultRegistry              = NewRegistry()
 	DefaultRegisterer Registerer = DefaultRegistry
-	DefaultDeliverer  Deliverer  = DefaultRegistry
+	DefaultGatherer   Gatherer   = DefaultRegistry
 )
 
 func init() {
@@ -115,24 +115,23 @@ type Registerer interface {
 	Unregister(Collector) bool
 }
 
-// Deliverer is the interface for the part of a registry in charge of delivering
-// the collected metrics, wich the same general implication as described for the
-// Registerer interface.
-type Deliverer interface {
-	// Deliver collects metrics from registered Collectors and returns them
-	// as lexicographically sorted MetricFamily protobufs. Even if an error
-	// occurs, Deliver attempts to collect as many metrics as
-	// possible. Hence, if a non-nil error is returned, the returned
-	// MetricFamily slice could be nil (in case of a fatal error that
-	// prevented any meaningful metric collection) or contain a number of
-	// MetricFamily protobufs, some of which might be incomplete, and some
-	// might be missing altogether. The returned error (which might be a
-	// multierror.Error) explains the details. In any case, the MetricFamily
-	// protobufs are consistent and valid for Prometheus to ingest (e.g. no
-	// duplicate metrics, no invalid identifiers). In scenarios where
-	// complete collection is critical, the returned MetricFamily protobufs
-	// should be disregarded if the returned error is non-nil.
-	Deliver() ([]*dto.MetricFamily, error)
+// Gatherer is the interface for the part of a registry in charge of gathering
+// the collected metrics into a number of MetricFamilies. The Gatherer interface
+// comes with the same general implication as described for the Registerer
+// interface.
+type Gatherer interface {
+	// Gather calls the Collect method of the registered Collectors and then
+	// gathers the collected metrics into a lexicographically sorted slice
+	// of MetricFamily protobufs. Even if an error occurs, Gather attempts
+	// to gather as many metrics as possible. Hence, if a non-nil error is
+	// returned, the returned MetricFamily slice could be nil (in case of a
+	// fatal error that prevented any meaningful metric collection) or
+	// contain a number of MetricFamily protobufs, some of which might be
+	// incomplete, and some might be missing altogether. The returned error
+	// (which might be a MultiError) explains the details. In scenarios
+	// where complete collection is critical, the returned MetricFamily
+	// protobufs should be disregarded if the returned error is non-nil.
+	Gather() ([]*dto.MetricFamily, error)
 }
 
 // Register registers the provided Collector with the DefaultRegisterer.
@@ -221,10 +220,10 @@ func (err AlreadyRegisteredError) Error() string {
 	return "duplicate metrics collector registration attempted"
 }
 
-// Registry registers Prometheus collectors, collects their metrics, and
-// delivers them for exposition. It implements Registerer and Deliverer. The
-// zero value is not usable. Use NewRegistry or NewPedanticRegistry to create
-// instances.
+// Registry registers Prometheus collectors, collects their metrics, and gathers
+// them into MetricFamilies for exposition. It implements Registerer and
+// Gatherer. The zero value is not usable. Create instances with NewRegistry or
+// NewPedanticRegistry.
 type Registry struct {
 	mtx                       sync.RWMutex
 	collectorsByID            map[uint64]Collector // ID is a hash of the descIDs.
@@ -361,8 +360,8 @@ func (r *Registry) MustRegister(cs ...Collector) {
 	}
 }
 
-// Deliver implements Deliverer.
-func (r *Registry) Deliver() ([]*dto.MetricFamily, error) {
+// Gather implements Gatherer.
+func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	var (
 		metricChan        = make(chan Metric, capMetricChan)
 		metricHashes      = map[uint64]struct{}{}