telegraf/plugins/inputs/cassandra/cassandra.go

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package cassandra
import (
"encoding/json"
"errors"
"fmt"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/inputs"
"io/ioutil"
"net/http"
"net/url"
//"reflect"
"strings"
)
type Server struct {
Host string
Username string
Password string
Port string
}
type Metric struct {
Jmx string
}
type JolokiaClient interface {
MakeRequest(req *http.Request) (*http.Response, error)
}
type JolokiaClientImpl struct {
client *http.Client
}
func (c JolokiaClientImpl) MakeRequest(req *http.Request) (*http.Response, error) {
return c.client.Do(req)
}
type Cassandra struct {
jClient JolokiaClient
Context string
Servers []Server
Metrics []Metric
}
type javaMetric struct {
server Server
metric Metric
acc telegraf.Accumulator
}
type cassandraMetric struct {
server Server
metric Metric
acc telegraf.Accumulator
}
type jmxMetric interface {
addTagsFields(out map[string]interface{})
}
func addServerTags(server Server, tags map[string]string) {
if server.Host != "" && server.Host != "localhost" &&
server.Host != "127.0.0.1" {
tags["host"] = server.Host
}
}
func newJavaMetric(server Server, metric Metric,
acc telegraf.Accumulator) *javaMetric {
return &javaMetric{server: server, metric: metric, acc: acc}
}
func newCassandraMetric(server Server, metric Metric,
acc telegraf.Accumulator) *cassandraMetric {
return &cassandraMetric{server: server, metric: metric, acc: acc}
}
func addValuesAsFields(values map[string]interface{}, fields map[string]interface{},
mname string) {
for k, v := range values {
if v != nil {
fields[mname+"_"+k] = v
}
}
}
func parseJmxMetricRequest(mbean string) map[string]string {
tokens := make(map[string]string)
classAndPairs := strings.Split(mbean, ":")
if classAndPairs[0] == "org.apache.cassandra.metrics" {
tokens["class"] = "cassandra"
} else if classAndPairs[0] == "java.lang" {
tokens["class"] = "java"
} else {
return tokens
}
pairs := strings.Split(classAndPairs[1], ",")
for _, pair := range pairs {
p := strings.Split(pair, "=")
tokens[p[0]] = p[1]
}
return tokens
}
func addTokensToTags(tokens map[string]string, tags map[string]string) {
for k, v := range tokens {
if k == "name" {
tags["mname"] = v // name seems to a reserved word in influxdb
} else if k == "class" || k == "type" {
continue // class and type are used in the metric name
} else {
tags[k] = v
}
}
}
func (j javaMetric) addTagsFields(out map[string]interface{}) {
tags := make(map[string]string)
fields := make(map[string]interface{})
a := out["request"].(map[string]interface{})
attribute := a["attribute"].(string)
mbean := a["mbean"].(string)
tokens := parseJmxMetricRequest(mbean)
addTokensToTags(tokens, tags)
addServerTags(j.server, tags)
if _, ok := tags["mname"]; !ok {
//Queries for a single value will not return a "name" tag in the response.
tags["mname"] = attribute
}
if values, ok := out["value"]; ok {
switch t := values.(type) {
case map[string]interface{}:
addValuesAsFields(values.(map[string]interface{}), fields, attribute)
case interface{}:
fields[attribute] = t
}
j.acc.AddFields(tokens["class"]+tokens["type"], fields, tags)
} else {
fmt.Printf("Missing key 'value' in '%s' output response\n%v\n",
j.metric.Jmx, out)
}
}
func addCassandraMetric(mbean string, c cassandraMetric,
values map[string]interface{}) {
tags := make(map[string]string)
fields := make(map[string]interface{})
tokens := parseJmxMetricRequest(mbean)
addTokensToTags(tokens, tags)
addServerTags(c.server, tags)
addValuesAsFields(values, fields, tags["mname"])
c.acc.AddFields(tokens["class"]+tokens["type"], fields, tags)
}
func (c cassandraMetric) addTagsFields(out map[string]interface{}) {
r := out["request"]
tokens := parseJmxMetricRequest(r.(map[string]interface{})["mbean"].(string))
// Requests with wildcards for keyspace or table names will return nested
// maps in the json response
if tokens["type"] == "Table" && (tokens["keyspace"] == "*" ||
tokens["scope"] == "*") {
if valuesMap, ok := out["value"]; ok {
for k, v := range valuesMap.(map[string]interface{}) {
addCassandraMetric(k, c, v.(map[string]interface{}))
}
} else {
fmt.Printf("Missing key 'value' in '%s' output response\n%v\n",
c.metric.Jmx, out)
return
}
} else {
if values, ok := out["value"]; ok {
addCassandraMetric(r.(map[string]interface{})["mbean"].(string),
c, values.(map[string]interface{}))
} else {
fmt.Printf("Missing key 'value' in '%s' output response\n%v\n",
c.metric.Jmx, out)
return
}
}
}
func (j *Cassandra) SampleConfig() string {
return `
# This is the context root used to compose the jolokia url
context = "/jolokia/read"
# List of cassandra servers exposing jolokia read service
[[cassandra.servers]]
# host can be skipped for localhost. host tag will be set to hostname()
host = "192.168.103.2"
port = "8180"
# username = "myuser"
# password = "mypassword"
# List of metrics collected on above servers
# Each metric consists of a jmx path. Pass or drop slice attributes will be
# supported in the future.
# This will collect all heap memory usage metrics from the jvm
[[cassandra..metrics]]
jmx = "/java.lang:type=Memory/HeapMemoryUsage"
# This will collect ReadLatency metrics for all keyspaces and tables.
# "type=Table" in the query works with Cassandra3.0. Older versions might need
# to use "type=ColumnFamily"
[[cassandra..metrics]]
jmx = "/org.apache.cassandra.metrics:type=Table,keyspace=*,scope=*,name=ReadL
atency"
`
}
func (j *Cassandra) Description() string {
return "Read Cassandra metrics through Jolokia"
}
func (j *Cassandra) getAttr(requestUrl *url.URL) (map[string]interface{}, error) {
// Create + send request
req, err := http.NewRequest("GET", requestUrl.String(), nil)
if err != nil {
return nil, err
}
resp, err := j.jClient.MakeRequest(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
// Process response
if resp.StatusCode != http.StatusOK {
err = fmt.Errorf("Response from url \"%s\" has status code %d (%s), expected %d (%s)",
requestUrl,
resp.StatusCode,
http.StatusText(resp.StatusCode),
http.StatusOK,
http.StatusText(http.StatusOK))
return nil, err
}
// read body
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
// Unmarshal json
var jsonOut map[string]interface{}
if err = json.Unmarshal([]byte(body), &jsonOut); err != nil {
return nil, errors.New("Error decoding JSON response")
}
return jsonOut, nil
}
func (c *Cassandra) Gather(acc telegraf.Accumulator) error {
context := c.Context
servers := c.Servers
metrics := c.Metrics
for _, server := range servers {
for _, metric := range metrics {
var m jmxMetric
if strings.HasPrefix(metric.Jmx, "/java.lang:") {
m = newJavaMetric(server, metric, acc)
} else if strings.HasPrefix(metric.Jmx,
"/org.apache.cassandra.metrics:") {
m = newCassandraMetric(server, metric, acc)
}
jmxPath := metric.Jmx
// Prepare URL
requestUrl, err := url.Parse("http://" + server.Host + ":" +
server.Port + context + jmxPath)
fmt.Printf("host %s url %s\n", server.Host, requestUrl)
if err != nil {
return err
}
if server.Username != "" || server.Password != "" {
requestUrl.User = url.UserPassword(server.Username, server.Password)
}
out, err := c.getAttr(requestUrl)
if out["status"] != 200.0 {
fmt.Printf("URL returned with status %v\n", out["status"])
continue
}
m.addTagsFields(out)
}
}
return nil
}
func init() {
inputs.Add("cassandra", func() telegraf.Input {
return &Cassandra{jClient: &JolokiaClientImpl{client: &http.Client{}}}
})
}