Add Nginx Plus API input (#4837)

plugins/inputs/nginx_plus_api/nginx_plus_api.go

@@ -0,0 +1,115 @@
+package nginx_plus_api
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+type NginxPlusApi struct {
+	Urls []string
+
+	ApiVersion int64
+
+	client *http.Client
+
+	ResponseTimeout internal.Duration
+}
+
+const (
+	// Default settings
+	defaultApiVersion = 3
+
+	// Paths
+	processesPath   = "processes"
+	connectionsPath = "connections"
+	sslPath         = "ssl"
+
+	httpRequestsPath    = "http/requests"
+	httpServerZonesPath = "http/server_zones"
+	httpUpstreamsPath   = "http/upstreams"
+	httpCachesPath      = "http/caches"
+
+	streamServerZonesPath = "stream/server_zones"
+	streamUpstreamsPath   = "stream/upstreams"
+)
+
+var sampleConfig = `
+  ## An array of API URI to gather stats.
+  urls = ["http://localhost/api"]
+
+  # Nginx API version, default: 3
+  # api_version = 3
+
+  # HTTP response timeout (default: 5s)
+  response_timeout = "5s"
+`
+
+func (n *NginxPlusApi) SampleConfig() string {
+	return sampleConfig
+}
+
+func (n *NginxPlusApi) Description() string {
+	return "Read Nginx Plus Api documentation"
+}
+
+func (n *NginxPlusApi) Gather(acc telegraf.Accumulator) error {
+	var wg sync.WaitGroup
+
+	// Create an HTTP client that is re-used for each
+	// collection interval
+
+	if n.ApiVersion == 0 {
+		n.ApiVersion = defaultApiVersion
+	}
+
+	if n.client == nil {
+		client, err := n.createHttpClient()
+		if err != nil {
+			return err
+		}
+		n.client = client
+	}
+
+	for _, u := range n.Urls {
+		addr, err := url.Parse(u)
+		if err != nil {
+			acc.AddError(fmt.Errorf("Unable to parse address '%s': %s", u, err))
+			continue
+		}
+
+		wg.Add(1)
+		go func(addr *url.URL) {
+			defer wg.Done()
+			n.gatherMetrics(addr, acc)
+		}(addr)
+	}
+
+	wg.Wait()
+	return nil
+}
+
+func (n *NginxPlusApi) createHttpClient() (*http.Client, error) {
+	if n.ResponseTimeout.Duration < time.Second {
+		n.ResponseTimeout.Duration = time.Second * 5
+	}
+
+	client := &http.Client{
+		Transport: &http.Transport{},
+		Timeout:   n.ResponseTimeout.Duration,
+	}
+
+	return client, nil
+}
+
+func init() {
+	inputs.Add("nginx_plus_api", func() telegraf.Input {
+		return &NginxPlusApi{}
+	})
+}