Fixed tags on mesos_task metrics.

Tagging values by executor_id can create quite a lot data series
in InfluxDB so we should stick to framework_id and server.

plugins/inputs/mesos/README.md

@@ -37,6 +37,9 @@ For more information, please check the [Mesos Observability Metrics](http://meso
   # ]
   ## Include mesos tasks statistics, default is false
   # slave_tasks = true
+  ## Should tags in slave task metrics be normalized? This will remove UUIDs from
+  ## task_id tag so we don't generate milions of series in InfluxDB, default is false
+  # slave_tasks_normalize = true
 ```
 
 By default this plugin is not configured to gather metrics from mesos. Since a mesos cluster can be deployed in numerous ways it does not provide any default
@@ -238,10 +241,6 @@ Mesos slave metric groups
 Mesos tasks metric groups
 
 - executor_id
-- executor_name
-- framework_id
-- source
-- statistics
 - cpus_limit
 - cpus_system_time_secs
 - cpus_user_time_secs
@@ -272,7 +271,6 @@ Mesos tasks metric groups
 - Tasks measurements have the following tags:
     - server
     - framework_id
-	- task_id
 
 ### Example Output:
 ```
@@ -299,13 +297,7 @@ master/messages_deactivate_framework=0 ...
 
 Meoso tasks metrics (if enabled):
 ```
-mesos-tasks,host=172.17.8.102,server=172.17.8.101,framework_id=e3060235-c4ed-4765-9d36-784e3beca07f-0000,task_id=hello-world.e4b5b497-2ccd-11e6-a659-0242fb222ce2
+> mesos_tasks,framework_id=20151016-120318-1243483658-5050-6139-0000,host=localhost,server=mesos-1
-cpus_limit=0.2,cpus_system_time_secs=142.49,cpus_user_time_secs=388.14,
+cpus_limit=0.2,cpus_system_time_secs=84.04,cpus_user_time_secs=1161,executor_id="some_app.5d9f3cf8-6b19-11e6-8d24-0242f3fd597e",
-mem_anon_bytes=359129088,mem_cache_bytes=3964928,
+mem_limit_bytes=348127232,mem_rss_bytes=310820864,timestamp=1472572204.22177 1472572204000000000...
-mem_critical_pressure_counter=0,mem_file_bytes=3964928,
-mem_limit_bytes=767557632,mem_low_pressure_counter=0,
-mem_mapped_file_bytes=114688,mem_medium_pressure_counter=0,
-mem_rss_bytes=359129088,mem_swap_bytes=0,mem_total_bytes=363094016,
-mem_total_memsw_bytes=363094016,mem_unevictable_bytes=0,
-timestamp=1465486052.70525 1465486053052811792...
 ```

plugins/inputs/mesos/mesos.go

@@ -459,7 +459,6 @@ func (m *Mesos) gatherSlaveTaskMetrics(address string, defaultPort string, acc t
 	}
 
 	for _, task := range metrics {
-		tags["task_id"] = task.ExecutorID
 		tags["framework_id"] = task.FrameworkID
 
 		jf := jsonparser.JSONFlattener{}
@@ -468,7 +467,9 @@ func (m *Mesos) gatherSlaveTaskMetrics(address string, defaultPort string, acc t
 		if err != nil {
 			return err
 		}
+
 		timestamp := time.Unix(int64(jf.Fields["timestamp"].(float64)), 0)
+		jf.Fields["executor_id"] = task.ExecutorID
 
 		acc.AddFields("mesos_tasks", jf.Fields, tags, timestamp)
 	}

plugins/inputs/mesos/mesos_test.go

@@ -9,7 +9,6 @@ import (
 	"os"
 	"testing"
 
-	jsonparser "github.com/influxdata/telegraf/plugins/parsers/json"
 	"github.com/influxdata/telegraf/testutil"
 )
 
@@ -217,10 +216,10 @@ func generateMetrics() {
 	}
 
 	slaveTaskMetrics = map[string]interface{}{
-		"executor_id":   fmt.Sprintf("task_%s", randUUID()),
+		"executor_id":   fmt.Sprintf("task_name.%s", randUUID()),
 		"executor_name": "Some task description",
 		"framework_id":  randUUID(),
-		"source":        fmt.Sprintf("task_source_%s", randUUID()),
+		"source":        fmt.Sprintf("task_source.%s", randUUID()),
 		"statistics": map[string]interface{}{
 			"cpus_limit":                    rand.Float64(),
 			"cpus_system_time_secs":         rand.Float64(),
@@ -338,17 +337,17 @@ func TestMesosSlave(t *testing.T) {
 
 	acc.AssertContainsFields(t, "mesos", slaveMetrics)
 
-	jf := jsonparser.JSONFlattener{}
+	expectedFields := make(map[string]interface{}, len(slaveTaskMetrics["statistics"].(map[string]interface{}))+1)
-	err = jf.FlattenJSON("", slaveTaskMetrics)
+	for k, v := range slaveTaskMetrics["statistics"].(map[string]interface{}) {
-
+		expectedFields[k] = v
-	if err != nil {
-		t.Errorf(err.Error())
 	}
+	expectedFields["executor_id"] = slaveTaskMetrics["executor_id"]
 
-	acc.AssertContainsFields(
+	acc.AssertContainsTaggedFields(
 		t,
 		"mesos_tasks",
-		slaveTaskMetrics["statistics"].(map[string]interface{}))
+		expectedFields,
+		map[string]string{"server": "127.0.0.1", "framework_id": slaveTaskMetrics["framework_id"].(string)})
 }
 
 func TestSlaveFilter(t *testing.T) {