Rename expvar plugin -> influxdbjson

plugins/all/all.go

@@ -7,9 +7,9 @@ import (
 	_ "github.com/influxdb/telegraf/plugins/disque"
 	_ "github.com/influxdb/telegraf/plugins/elasticsearch"
 	_ "github.com/influxdb/telegraf/plugins/exec"
-	_ "github.com/influxdb/telegraf/plugins/expvar"
 	_ "github.com/influxdb/telegraf/plugins/haproxy"
 	_ "github.com/influxdb/telegraf/plugins/httpjson"
+	_ "github.com/influxdb/telegraf/plugins/influxdbjson"
 	_ "github.com/influxdb/telegraf/plugins/jolokia"
 	_ "github.com/influxdb/telegraf/plugins/kafka_consumer"
 	_ "github.com/influxdb/telegraf/plugins/leofs"

plugins/influxdbjson/README.md

@@ -1,12 +1,11 @@
-# expvar plugin
+# influxdbjson plugin
 
-The expvar plugin collects InfluxDB-style expvar data from JSON endpoints.
+The influxdbjson plugin collects InfluxDB-formatted data from JSON endpoints.
 
 With a configuration of:
 
 ```toml
-[plugins.expvar]
+[[plugins.influxdbjson]]
-  [[plugins.expvar.services]]
 	name = "produce"
 	urls = [
 		"http://127.0.0.1:8086/debug/vars",
@@ -59,10 +58,10 @@ And if 192.168.2.1 responds like so:
 Then the collected metrics will be:
 
 ```
-expvar_produce_fruit,expvar_url='http://127.0.0.1:8086/debug/vars',kind='apple' inventory=371.0,sold=112.0
+influxdbjson_produce_fruit,influxdbjson_url='http://127.0.0.1:8086/debug/vars',kind='apple' inventory=371.0,sold=112.0
-expvar_produce_fruit,expvar_url='http://127.0.0.1:8086/debug/vars',kind='banana' inventory=1000.0,sold=403.0
+influxdbjson_produce_fruit,influxdbjson_url='http://127.0.0.1:8086/debug/vars',kind='banana' inventory=1000.0,sold=403.0
 
-expvar_produce_transactions,expvar_url='http://192.168.2.1:8086/debug/vars' total=100.0,balance=184.75
+influxdbjson_produce_transactions,influxdbjson_url='http://192.168.2.1:8086/debug/vars' total=100.0,balance=184.75
 ```
 
 There are two important details to note about the collected metrics:

plugins/influxdbjson/influxdb_json.go

@@ -1,4 +1,4 @@
-package expvar
+package influxdbjson
 
 import (
 	"encoding/json"
@@ -10,54 +10,61 @@ import (
 	"github.com/influxdb/telegraf/plugins"
 )
 
-var sampleConfig = `
+type InfluxDBJSON struct {
-  # Specify services via an array of tables
-  [[plugins.expvar.services]]
-    # Name for the service being polled
-    name = "influxdb"
-
-    # Multiple URLs from which to read expvars
-    urls = [
-      "http://localhost:8086/debug/vars"
-    ]
-`
-
-type Expvar struct {
-	Services []Service
-}
-
-type Service struct {
 	Name string
 	URLs []string `toml:"urls"`
 }
 
-func (*Expvar) Description() string {
+func (*InfluxDBJSON) Description() string {
-	return "Read InfluxDB-style expvar metrics from one or more HTTP endpoints"
+	return "Read InfluxDB-formatted JSON metrics from one or more HTTP endpoints"
 }
 
-func (*Expvar) SampleConfig() string {
+func (*InfluxDBJSON) SampleConfig() string {
-	return sampleConfig
+	return `
+  # Reads InfluxDB-formatted JSON from given URLs. For example,
+	# monitoring a URL which responded with a JSON object formatted like this:
+	#
+  #   {
+  #     "(ignored_key)": {
+  #       "name": "connections",
+  #       "tags": {
+  #         "host": "foo"
+  #       },
+  #       "values": {
+  #         "avg_ms": 1.234,
+  #       }
+  #     }
+  #   }
+  #
+	# with configuration of { name = "server", urls = ["http://127.0.0.1:8086/x"] }
+  #
+	# Would result in this recorded metric:
+	#
+  #   influxdbjson_server_connections,influxdbjson_url='http://127.0.0.1:8086/x',host='foo' avg_ms=1.234
+  [[plugins.influxdbjson]]
+	# Name to use for measurement
+	name = "influxdb"
+
+	# Multiple URLs from which to read InfluxDB-formatted JSON
+	urls = [
+		"http://localhost:8086/debug/vars"
+	]
+`
 }
 
-func (e *Expvar) Gather(acc plugins.Accumulator) error {
+func (i *InfluxDBJSON) Gather(acc plugins.Accumulator) error {
 	var wg sync.WaitGroup
 
-	totalURLs := 0
+	errorChannel := make(chan error, len(i.URLs))
-	for _, service := range e.Services {
-		totalURLs += len(service.URLs)
-	}
-	errorChannel := make(chan error, totalURLs)
 
-	for _, service := range e.Services {
+	for _, u := range i.URLs {
-		for _, u := range service.URLs {
 		wg.Add(1)
-			go func(service Service, url string) {
+		go func(url string) {
 			defer wg.Done()
-				if err := e.gatherURL(acc, service, url); err != nil {
+			if err := i.gatherURL(acc, url); err != nil {
 				errorChannel <- err
 			}
-			}(service, u)
+		}(u)
-		}
 	}
 
 	wg.Wait()
@@ -84,14 +91,12 @@ type point struct {
 // Gathers data from a particular URL
 // Parameters:
 //     acc    : The telegraf Accumulator to use
-//     service: the service being queried
 //     url    : endpoint to send request to
 //
 // Returns:
 //     error: Any error that may have occurred
-func (e *Expvar) gatherURL(
+func (i *InfluxDBJSON) gatherURL(
 	acc plugins.Accumulator,
-	service Service,
 	url string,
 ) error {
 	resp, err := http.Get(url)
@@ -107,7 +112,7 @@ func (e *Expvar) gatherURL(
 	if t, err := dec.Token(); err != nil {
 		return err
 	} else if t != json.Delim('{') {
-		return errors.New("expvars must be a JSON object")
+		return errors.New("document root must be a JSON object")
 	}
 
 	// Loop through rest of object
@@ -117,7 +122,7 @@ func (e *Expvar) gatherURL(
 			break
 		}
 
-		// Read in a string key. We actually don't care about the top-level keys
+		// Read in a string key. We don't do anything with the top-level keys, so it's discarded.
 		_, err := dec.Token()
 		if err != nil {
 			return err
@@ -131,14 +136,16 @@ func (e *Expvar) gatherURL(
 			continue
 		}
 
+		// If the object was a point, but was not fully initialized, ignore it and move on.
 		if p.Name == "" || p.Tags == nil || p.Values == nil || len(p.Values) == 0 {
 			continue
 		}
 
-		p.Tags["expvar_url"] = url
+		// Add a tag to indicate the source of the data.
+		p.Tags["influxdbjson_url"] = url
 
 		acc.AddFields(
-			service.Name+"_"+p.Name,
+			i.Name+"_"+p.Name,
 			p.Values,
 			p.Tags,
 		)
@@ -148,7 +155,7 @@ func (e *Expvar) gatherURL(
 }
 
 func init() {
-	plugins.Add("expvar", func() plugins.Plugin {
+	plugins.Add("influxdbjson", func() plugins.Plugin {
-		return &Expvar{}
+		return &InfluxDBJSON{}
 	})
 }

plugins/influxdbjson/influxdb_json_test.go

@@ -1,10 +1,11 @@
-package expvar
+package influxdbjson_test
 
 import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
+	"github.com/influxdb/telegraf/plugins/influxdbjson"
 	"github.com/influxdb/telegraf/testutil"
 	"github.com/stretchr/testify/require"
 )
@@ -55,7 +56,7 @@ func TestBasic(t *testing.T) {
 }
 `
 	fakeServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if r.URL.Path == "/expvar" {
+		if r.URL.Path == "/endpoint" {
 			_, _ = w.Write([]byte(js))
 		} else {
 			w.WriteHeader(http.StatusNotFound)
@@ -63,17 +64,13 @@ func TestBasic(t *testing.T) {
 	}))
 	defer fakeServer.Close()
 
-	expvar := &Expvar{
+	plugin := &influxdbjson.InfluxDBJSON{
-		Services: []Service{
-			{
 		Name: "test",
-				URLs: []string{fakeServer.URL + "/expvar"},
+		URLs: []string{fakeServer.URL + "/endpoint"},
-			},
-		},
 	}
 
 	var acc testutil.Accumulator
-	require.NoError(t, expvar.Gather(&acc))
+	require.NoError(t, plugin.Gather(&acc))
 
 	require.Len(t, acc.Points, 2)
 	require.NoError(t, acc.ValidateTaggedFieldsValue(
@@ -88,7 +85,7 @@ func TestBasic(t *testing.T) {
 		},
 		map[string]string{
 			"id":               "ex1",
-			"expvar_url": fakeServer.URL + "/expvar",
+			"influxdbjson_url": fakeServer.URL + "/endpoint",
 		},
 	))
 	require.NoError(t, acc.ValidateTaggedFieldsValue(
@@ -98,7 +95,7 @@ func TestBasic(t *testing.T) {
 		},
 		map[string]string{
 			"id":               "ex2",
-			"expvar_url": fakeServer.URL + "/expvar",
+			"influxdbjson_url": fakeServer.URL + "/endpoint",
 		},
 	))
 }