Add PHPFPM stat

- HTTP status or Socket status
- Collect those metric:
    accepted conn:
    listen queue:
    max listen queue:
    listen queue len:
    idle processes:
    active processes:
    total processes:
    max active processes:
    max children reached:
    slow requests:
- Tag metric with: `host` and `pool` name

Closes #255

plugins/phpfpm/phpfpm_test.go

@@ -0,0 +1,85 @@
+package phpfpm
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/influxdb/telegraf/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"net/http"
+	"net/http/httptest"
+)
+
+func TestPhpFpmGeneratesMetrics(t *testing.T) {
+	//We create a fake server to return test data
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, outputSample)
+	}))
+	defer ts.Close()
+
+	//Now we tested again above server, with our authentication data
+	r := &phpfpm{
+		Urls: []string{ts.URL},
+	}
+
+	var acc testutil.Accumulator
+
+	err := r.Gather(&acc)
+	require.NoError(t, err)
+
+	tags := map[string]string{
+		"url":  ts.Listener.Addr().String(),
+		"pool": "www",
+	}
+	assert.NoError(t, acc.ValidateTaggedValue("accepted_conn", int64(3), tags))
+
+	checkInt := []struct {
+		name  string
+		value int64
+	}{
+		{"accepted_conn", 3},
+		{"listen_queue", 1},
+		{"max_listen_queue", 0},
+		{"listen_queue_len", 0},
+		{"idle_processes", 1},
+		{"active_processes", 1},
+		{"total_processes", 2},
+		{"max_active_processes", 1},
+		{"max_children_reached", 2},
+		{"slow_requests", 1},
+	}
+
+	for _, c := range checkInt {
+		assert.Equal(t, true, acc.CheckValue(c.name, c.value))
+	}
+}
+
+//When not passing server config, we default to localhost
+//We just want to make sure we did request stat from localhost
+func TestHaproxyDefaultGetFromLocalhost(t *testing.T) {
+	r := &phpfpm{}
+
+	var acc testutil.Accumulator
+
+	err := r.Gather(&acc)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "127.0.0.1/status")
+}
+
+const outputSample = `
+pool:                 www
+process manager:      dynamic
+start time:           11/Oct/2015:23:38:51 +0000
+start since:          1991
+accepted conn:        3
+listen queue:         1
+max listen queue:     0
+listen queue len:     0
+idle processes:       1
+active processes:     1
+total processes:      2
+max active processes: 1
+max children reached: 2
+slow requests:        1
+`