telegraf/plugins/outputs/azure_monitor/azure_monitor.go

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package azure_monitor
import (
"bytes"
"compress/gzip"
"encoding/binary"
"encoding/json"
"fmt"
"hash/fnv"
"io/ioutil"
"log"
"net/http"
"regexp"
"strings"
"time"
"github.com/Azure/go-autorest/autorest"
"github.com/Azure/go-autorest/autorest/azure/auth"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/metric"
"github.com/influxdata/telegraf/plugins/outputs"
"github.com/influxdata/telegraf/selfstat"
)
// AzureMonitor allows publishing of metrics to the Azure Monitor custom metrics
// service
type AzureMonitor struct {
Timeout internal.Duration
NamespacePrefix string `toml:"namespace_prefix"`
StringsAsDimensions bool `toml:"strings_as_dimensions"`
Region string
ResourceID string `toml:"resource_id"`
url string
auth autorest.Authorizer
client *http.Client
cache map[time.Time]map[uint64]*aggregate
timeFunc func() time.Time
MetricOutsideWindow selfstat.Stat
}
type dimension struct {
name string
value string
}
type aggregate struct {
name string
min float64
max float64
sum float64
count int64
dimensions []dimension
updated bool
}
const (
defaultRequestTimeout = time.Second * 5
defaultNamespacePrefix = "Telegraf/"
defaultAuthResource = "https://monitoring.azure.com/"
vmInstanceMetadataURL = "http://169.254.169.254/metadata/instance?api-version=2017-12-01"
resourceIDTemplate = "/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/virtualMachines/%s"
urlTemplate = "https://%s.monitoring.azure.com%s/metrics"
maxRequestBodySize = 4000000
)
var sampleConfig = `
## Timeout for HTTP writes.
# timeout = "20s"
## Set the namespace prefix, defaults to "Telegraf/<input-name>".
# namespace_prefix = "Telegraf/"
## Azure Monitor doesn't have a string value type, so convert string
## fields to dimensions (a.k.a. tags) if enabled. Azure Monitor allows
## a maximum of 10 dimensions so Telegraf will only send the first 10
## alphanumeric dimensions.
# strings_as_dimensions = false
## Both region and resource_id must be set or be available via the
## Instance Metadata service on Azure Virtual Machines.
#
## Azure Region to publish metrics against.
## ex: region = "southcentralus"
# region = ""
#
## The Azure Resource ID against which metric will be logged, e.g.
## ex: resource_id = "/subscriptions/<subscription_id>/resourceGroups/<resource_group>/providers/Microsoft.Compute/virtualMachines/<vm_name>"
# resource_id = ""
`
// Description provides a description of the plugin
func (a *AzureMonitor) Description() string {
return "Send aggregate metrics to Azure Monitor"
}
// SampleConfig provides a sample configuration for the plugin
func (a *AzureMonitor) SampleConfig() string {
return sampleConfig
}
// Connect initializes the plugin and validates connectivity
func (a *AzureMonitor) Connect() error {
a.cache = make(map[time.Time]map[uint64]*aggregate, 36)
if a.Timeout.Duration == 0 {
a.Timeout.Duration = defaultRequestTimeout
}
a.client = &http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
},
Timeout: a.Timeout.Duration,
}
if a.NamespacePrefix == "" {
a.NamespacePrefix = defaultNamespacePrefix
}
var err error
var region string
var resourceID string
if a.Region == "" || a.ResourceID == "" {
// Pull region and resource identifier
region, resourceID, err = vmInstanceMetadata(a.client)
if err != nil {
return err
}
}
if a.Region != "" {
region = a.Region
}
if a.ResourceID != "" {
resourceID = a.ResourceID
}
if resourceID == "" {
return fmt.Errorf("no resource ID configured or available via VM instance metadata")
} else if region == "" {
return fmt.Errorf("no region configured or available via VM instance metadata")
}
a.url = fmt.Sprintf(urlTemplate, region, resourceID)
log.Printf("D! Writing to Azure Monitor URL: %s", a.url)
a.auth, err = auth.NewAuthorizerFromEnvironmentWithResource(defaultAuthResource)
if err != nil {
return nil
}
a.Reset()
tags := map[string]string{
"region": region,
"resource_id": resourceID,
}
a.MetricOutsideWindow = selfstat.Register("azure_monitor", "metric_outside_window", tags)
return nil
}
// vmMetadata retrieves metadata about the current Azure VM
func vmInstanceMetadata(c *http.Client) (string, string, error) {
req, err := http.NewRequest("GET", vmInstanceMetadataURL, nil)
if err != nil {
return "", "", fmt.Errorf("error creating request: %v", err)
}
req.Header.Set("Metadata", "true")
resp, err := c.Do(req)
if err != nil {
return "", "", err
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return "", "", err
}
if resp.StatusCode >= 300 || resp.StatusCode < 200 {
return "", "", fmt.Errorf("unable to fetch instance metadata: [%v] %s", resp.StatusCode, body)
}
// VirtualMachineMetadata contains information about a VM from the metadata service
type VirtualMachineMetadata struct {
Compute struct {
Location string `json:"location"`
Name string `json:"name"`
ResourceGroupName string `json:"resourceGroupName"`
SubscriptionID string `json:"subscriptionId"`
} `json:"compute"`
}
var metadata VirtualMachineMetadata
if err := json.Unmarshal(body, &metadata); err != nil {
return "", "", err
}
region := metadata.Compute.Location
resourceID := fmt.Sprintf(
resourceIDTemplate,
metadata.Compute.SubscriptionID,
metadata.Compute.ResourceGroupName,
metadata.Compute.Name,
)
return region, resourceID, nil
}
// Close shuts down an any active connections
func (a *AzureMonitor) Close() error {
a.client = nil
return nil
}
type azureMonitorMetric struct {
Time time.Time `json:"time"`
Data *azureMonitorData `json:"data"`
}
type azureMonitorData struct {
BaseData *azureMonitorBaseData `json:"baseData"`
}
type azureMonitorBaseData struct {
Metric string `json:"metric"`
Namespace string `json:"namespace"`
DimensionNames []string `json:"dimNames"`
Series []*azureMonitorSeries `json:"series"`
}
type azureMonitorSeries struct {
DimensionValues []string `json:"dimValues"`
Min float64 `json:"min"`
Max float64 `json:"max"`
Sum float64 `json:"sum"`
Count int64 `json:"count"`
}
// Write writes metrics to the remote endpoint
func (a *AzureMonitor) Write(metrics []telegraf.Metric) error {
azmetrics := make(map[uint64]*azureMonitorMetric, len(metrics))
for _, m := range metrics {
id := hashIDWithTagKeysOnly(m)
if azm, ok := azmetrics[id]; !ok {
amm, err := translate(m, a.NamespacePrefix)
if err != nil {
log.Printf("E! [outputs.azure_monitor]: could not create azure metric for %q; discarding point", m.Name())
continue
}
azmetrics[id] = amm
} else {
amm, err := translate(m, a.NamespacePrefix)
if err != nil {
log.Printf("E! [outputs.azure_monitor]: could not create azure metric for %q; discarding point", m.Name())
continue
}
azmetrics[id].Data.BaseData.Series = append(
azm.Data.BaseData.Series,
amm.Data.BaseData.Series...,
)
}
}
if len(azmetrics) == 0 {
return nil
}
var body []byte
for _, m := range azmetrics {
// Azure Monitor accepts new batches of points in new-line delimited
// JSON, following RFC 4288 (see https://github.com/ndjson/ndjson-spec).
jsonBytes, err := json.Marshal(&m)
if err != nil {
return err
}
// Azure Monitor's maximum request body size of 4MB. Send batches that
// exceed this size via separate write requests.
if (len(body) + len(jsonBytes) + 1) > maxRequestBodySize {
err := a.send(body)
if err != nil {
return err
}
body = nil
}
body = append(body, jsonBytes...)
body = append(body, '\n')
}
return a.send(body)
}
func (a *AzureMonitor) send(body []byte) error {
var buf bytes.Buffer
g := gzip.NewWriter(&buf)
if _, err := g.Write(body); err != nil {
return err
}
if err := g.Close(); err != nil {
return err
}
req, err := http.NewRequest("POST", a.url, &buf)
if err != nil {
return err
}
req.Header.Set("Content-Encoding", "gzip")
req.Header.Set("Content-Type", "application/x-ndjson")
// Add the authorization header. WithAuthorization will automatically
// refresh the token if needed.
req, err = autorest.CreatePreparer(a.auth.WithAuthorization()).Prepare(req)
if err != nil {
return fmt.Errorf("unable to fetch authentication credentials: %v", err)
}
resp, err := a.client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
_, err = ioutil.ReadAll(resp.Body)
if err != nil || resp.StatusCode < 200 || resp.StatusCode > 299 {
return fmt.Errorf("failed to write batch: [%v] %s", resp.StatusCode, resp.Status)
}
return nil
}
func hashIDWithTagKeysOnly(m telegraf.Metric) uint64 {
h := fnv.New64a()
h.Write([]byte(m.Name()))
h.Write([]byte("\n"))
for _, tag := range m.TagList() {
h.Write([]byte(tag.Key))
h.Write([]byte("\n"))
}
b := make([]byte, binary.MaxVarintLen64)
n := binary.PutUvarint(b, uint64(m.Time().UnixNano()))
h.Write(b[:n])
h.Write([]byte("\n"))
return h.Sum64()
}
func translate(m telegraf.Metric, prefix string) (*azureMonitorMetric, error) {
var dimensionNames []string
var dimensionValues []string
for _, tag := range m.TagList() {
// Azure custom metrics service supports up to 10 dimensions
if len(dimensionNames) > 10 {
continue
}
if tag.Key == "" || tag.Value == "" {
continue
}
dimensionNames = append(dimensionNames, tag.Key)
dimensionValues = append(dimensionValues, tag.Value)
}
min, err := getFloatField(m, "min")
if err != nil {
return nil, err
}
max, err := getFloatField(m, "max")
if err != nil {
return nil, err
}
sum, err := getFloatField(m, "sum")
if err != nil {
return nil, err
}
count, err := getIntField(m, "count")
if err != nil {
return nil, err
}
mn, ns := "Missing", "Missing"
names := strings.SplitN(m.Name(), "-", 2)
if len(names) > 1 {
mn = names[1]
}
if len(names) > 0 {
ns = names[0]
}
ns = prefix + ns
return &azureMonitorMetric{
Time: m.Time(),
Data: &azureMonitorData{
BaseData: &azureMonitorBaseData{
Metric: mn,
Namespace: ns,
DimensionNames: dimensionNames,
Series: []*azureMonitorSeries{
{
DimensionValues: dimensionValues,
Min: min,
Max: max,
Sum: sum,
Count: count,
},
},
},
},
}, nil
}
func getFloatField(m telegraf.Metric, key string) (float64, error) {
fv, ok := m.GetField(key)
if !ok {
return 0, fmt.Errorf("missing field: %s", key)
}
if value, ok := fv.(float64); ok {
return value, nil
}
return 0, fmt.Errorf("unexpected type: %s: %T", key, fv)
}
func getIntField(m telegraf.Metric, key string) (int64, error) {
fv, ok := m.GetField(key)
if !ok {
return 0, fmt.Errorf("missing field: %s", key)
}
if value, ok := fv.(int64); ok {
return value, nil
}
return 0, fmt.Errorf("unexpected type: %s: %T", key, fv)
}
// Add will append a metric to the output aggregate
func (a *AzureMonitor) Add(m telegraf.Metric) {
// Azure Monitor only supports aggregates 30 minutes into the past and 4
// minutes into the future. Future metrics are dropped when pushed.
t := m.Time()
tbucket := time.Date(t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), 0, 0, t.Location())
if tbucket.Before(a.timeFunc().Add(-time.Minute * 30)) {
a.MetricOutsideWindow.Incr(1)
return
}
// Azure Monitor doesn't have a string value type, so convert string fields
// to dimensions (a.k.a. tags) if enabled.
if a.StringsAsDimensions {
for _, f := range m.FieldList() {
if v, ok := f.Value.(string); ok {
m.AddTag(f.Key, v)
}
}
}
for _, f := range m.FieldList() {
fv, ok := convert(f.Value)
if !ok {
continue
}
// Azure Monitor does not support fields so the field name is appended
// to the metric name.
name := m.Name() + "-" + sanitize(f.Key)
id := hashIDWithField(m.HashID(), f.Key)
_, ok = a.cache[tbucket]
if !ok {
// Time bucket does not exist and needs to be created.
a.cache[tbucket] = make(map[uint64]*aggregate)
}
// Fetch existing aggregate
var agg *aggregate
agg, ok = a.cache[tbucket][id]
if !ok {
agg := &aggregate{
name: name,
min: fv,
max: fv,
sum: fv,
count: 1,
}
for _, tag := range m.TagList() {
dim := dimension{
name: tag.Key,
value: tag.Value,
}
agg.dimensions = append(agg.dimensions, dim)
}
agg.updated = true
a.cache[tbucket][id] = agg
continue
}
if fv < agg.min {
agg.min = fv
}
if fv > agg.max {
agg.max = fv
}
agg.sum += fv
agg.count++
agg.updated = true
}
}
func convert(in interface{}) (float64, bool) {
switch v := in.(type) {
case int64:
return float64(v), true
case uint64:
return float64(v), true
case float64:
return v, true
case bool:
if v {
return 1, true
}
return 0, true
default:
return 0, false
}
}
var invalidNameCharRE = regexp.MustCompile(`[^a-zA-Z0-9_]`)
func sanitize(value string) string {
return invalidNameCharRE.ReplaceAllString(value, "_")
}
func hashIDWithField(id uint64, fk string) uint64 {
h := fnv.New64a()
b := make([]byte, binary.MaxVarintLen64)
n := binary.PutUvarint(b, id)
h.Write(b[:n])
h.Write([]byte("\n"))
h.Write([]byte(fk))
h.Write([]byte("\n"))
return h.Sum64()
}
// Push sends metrics to the output metric buffer
func (a *AzureMonitor) Push() []telegraf.Metric {
var metrics []telegraf.Metric
for tbucket, aggs := range a.cache {
// Do not send metrics early
if tbucket.After(a.timeFunc().Add(-time.Minute)) {
continue
}
for _, agg := range aggs {
// Only send aggregates that have had an update since the last push.
if !agg.updated {
continue
}
tags := make(map[string]string, len(agg.dimensions))
for _, tag := range agg.dimensions {
tags[tag.name] = tag.value
}
m, err := metric.New(agg.name,
tags,
map[string]interface{}{
"min": agg.min,
"max": agg.max,
"sum": agg.sum,
"count": agg.count,
},
tbucket,
)
if err != nil {
log.Printf("E! [outputs.azure_monitor]: could not create metric for aggregation %q; discarding point", agg.name)
}
metrics = append(metrics, m)
}
}
return metrics
}
// Reset clears the cache of aggregate metrics
func (a *AzureMonitor) Reset() {
for tbucket := range a.cache {
// Remove aggregates older than 30 minutes
if tbucket.Before(a.timeFunc().Add(-time.Minute * 30)) {
delete(a.cache, tbucket)
continue
}
// Metrics updated within the latest 1m have not been pushed and should
// not be cleared.
if tbucket.After(a.timeFunc().Add(-time.Minute)) {
continue
}
for id := range a.cache[tbucket] {
a.cache[tbucket][id].updated = false
}
}
}
func init() {
outputs.Add("azure_monitor", func() telegraf.Output {
return &AzureMonitor{
timeFunc: time.Now,
}
})
}