mirror of https://github.com/prometheus/prometheus
281 lines
9.3 KiB
Go
281 lines
9.3 KiB
Go
// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"context"
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"encoding/json"
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"fmt"
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"io"
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"net"
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"net/http"
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"os"
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"strconv"
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"strings"
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"time"
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"github.com/alecthomas/kingpin/v2"
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"github.com/go-kit/log"
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"github.com/go-kit/log/level"
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"github.com/prometheus/common/model"
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"github.com/prometheus/prometheus/discovery/targetgroup"
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"github.com/prometheus/prometheus/documentation/examples/custom-sd/adapter"
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"github.com/prometheus/prometheus/util/strutil"
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)
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var (
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a = kingpin.New("sd adapter usage", "Tool to generate file_sd target files for unimplemented SD mechanisms.")
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outputFile = a.Flag("output.file", "Output file for file_sd compatible file.").Default("custom_sd.json").String()
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listenAddress = a.Flag("listen.address", "The address the Consul HTTP API is listening on for requests.").Default("localhost:8500").String()
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logger log.Logger
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// addressLabel is the name for the label containing a target's address.
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addressLabel = model.MetaLabelPrefix + "consul_address"
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// nodeLabel is the name for the label containing a target's node name.
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nodeLabel = model.MetaLabelPrefix + "consul_node"
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// tagsLabel is the name of the label containing the tags assigned to the target.
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tagsLabel = model.MetaLabelPrefix + "consul_tags"
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// serviceAddressLabel is the name of the label containing the (optional) service address.
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serviceAddressLabel = model.MetaLabelPrefix + "consul_service_address"
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// servicePortLabel is the name of the label containing the service port.
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servicePortLabel = model.MetaLabelPrefix + "consul_service_port"
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// serviceIDLabel is the name of the label containing the service ID.
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serviceIDLabel = model.MetaLabelPrefix + "consul_service_id"
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)
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// CatalogService is copied from https://github.com/hashicorp/consul/blob/master/api/catalog.go
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// this struct represents the response from a /service/<service-name> request.
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// Consul License: https://github.com/hashicorp/consul/blob/master/LICENSE
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type CatalogService struct {
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ID string
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Node string
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Address string
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Datacenter string
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TaggedAddresses map[string]string
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NodeMeta map[string]string
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ServiceID string
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ServiceName string
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ServiceAddress string
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ServiceTags []string
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ServicePort int
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ServiceEnableTagOverride bool
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CreateIndex uint64
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ModifyIndex uint64
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}
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// Note: create a config struct for your custom SD type here.
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type sdConfig struct {
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Address string
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TagSeparator string
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RefreshInterval int
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}
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// Note: This is the struct with your implementation of the Discoverer interface (see Run function).
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// Discovery retrieves target information from a Consul server and updates them via watches.
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type discovery struct {
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address string
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refreshInterval int
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tagSeparator string
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logger log.Logger
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oldSourceList map[string]bool
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}
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func (d *discovery) parseServiceNodes(resp *http.Response, name string) (*targetgroup.Group, error) {
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var nodes []*CatalogService
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tgroup := targetgroup.Group{
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Source: name,
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Labels: make(model.LabelSet),
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}
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defer func() {
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io.Copy(io.Discard, resp.Body)
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resp.Body.Close()
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}()
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b, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, err
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}
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err = json.Unmarshal(b, &nodes)
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if err != nil {
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return &tgroup, err
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}
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tgroup.Targets = make([]model.LabelSet, 0, len(nodes))
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for _, node := range nodes {
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// We surround the separated list with the separator as well. This way regular expressions
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// in relabeling rules don't have to consider tag positions.
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tags := "," + strings.Join(node.ServiceTags, ",") + ","
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// If the service address is not empty it should be used instead of the node address
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// since the service may be registered remotely through a different node.
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var addr string
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if node.ServiceAddress != "" {
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addr = net.JoinHostPort(node.ServiceAddress, fmt.Sprintf("%d", node.ServicePort))
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} else {
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addr = net.JoinHostPort(node.Address, fmt.Sprintf("%d", node.ServicePort))
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}
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target := model.LabelSet{model.AddressLabel: model.LabelValue(addr)}
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labels := model.LabelSet{
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model.AddressLabel: model.LabelValue(addr),
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model.LabelName(addressLabel): model.LabelValue(node.Address),
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model.LabelName(nodeLabel): model.LabelValue(node.Node),
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model.LabelName(tagsLabel): model.LabelValue(tags),
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model.LabelName(serviceAddressLabel): model.LabelValue(node.ServiceAddress),
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model.LabelName(servicePortLabel): model.LabelValue(strconv.Itoa(node.ServicePort)),
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model.LabelName(serviceIDLabel): model.LabelValue(node.ServiceID),
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}
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tgroup.Labels = labels
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// Add all key/value pairs from the node's metadata as their own labels.
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for k, v := range node.NodeMeta {
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name := strutil.SanitizeLabelName(k)
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tgroup.Labels[model.LabelName(model.MetaLabelPrefix+name)] = model.LabelValue(v)
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}
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tgroup.Targets = append(tgroup.Targets, target)
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}
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return &tgroup, nil
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}
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// Note: you must implement this function for your discovery implementation as part of the
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// Discoverer interface. Here you should query your SD for it's list of known targets, determine
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// which of those targets you care about (for example, which of Consuls known services do you want
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// to scrape for metrics), and then send those targets as a target.TargetGroup to the ch channel.
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func (d *discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
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for c := time.Tick(time.Duration(d.refreshInterval) * time.Second); ; {
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var srvs map[string][]string
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resp, err := http.Get(fmt.Sprintf("http://%s/v1/catalog/services", d.address))
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if err != nil {
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level.Error(d.logger).Log("msg", "Error getting services list", "err", err)
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time.Sleep(time.Duration(d.refreshInterval) * time.Second)
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continue
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}
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b, err := io.ReadAll(resp.Body)
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io.Copy(io.Discard, resp.Body)
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resp.Body.Close()
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if err != nil {
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level.Error(d.logger).Log("msg", "Error reading services list", "err", err)
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time.Sleep(time.Duration(d.refreshInterval) * time.Second)
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continue
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}
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err = json.Unmarshal(b, &srvs)
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resp.Body.Close()
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if err != nil {
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level.Error(d.logger).Log("msg", "Error parsing services list", "err", err)
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time.Sleep(time.Duration(d.refreshInterval) * time.Second)
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continue
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}
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var tgs []*targetgroup.Group
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// Note that we treat errors when querying specific consul services as fatal for this
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// iteration of the time.Tick loop. It's better to have some stale targets than an incomplete
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// list of targets simply because there may have been a timeout. If the service is actually
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// gone as far as consul is concerned, that will be picked up during the next iteration of
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// the outer loop.
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newSourceList := make(map[string]bool)
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for name := range srvs {
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if name == "consul" {
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continue
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}
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resp, err := http.Get(fmt.Sprintf("http://%s/v1/catalog/service/%s", d.address, name))
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if err != nil {
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level.Error(d.logger).Log("msg", "Error getting services nodes", "service", name, "err", err)
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break
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}
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tg, err := d.parseServiceNodes(resp, name)
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if err != nil {
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level.Error(d.logger).Log("msg", "Error parsing services nodes", "service", name, "err", err)
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break
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}
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tgs = append(tgs, tg)
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newSourceList[tg.Source] = true
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}
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// When targetGroup disappear, send an update with empty targetList.
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for key := range d.oldSourceList {
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if !newSourceList[key] {
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tgs = append(tgs, &targetgroup.Group{
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Source: key,
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})
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}
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}
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d.oldSourceList = newSourceList
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if err == nil {
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// We're returning all Consul services as a single targetgroup.
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ch <- tgs
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}
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// Wait for ticker or exit when ctx is closed.
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select {
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case <-c:
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continue
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case <-ctx.Done():
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return
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}
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}
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}
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func newDiscovery(conf sdConfig) (*discovery, error) {
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cd := &discovery{
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address: conf.Address,
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refreshInterval: conf.RefreshInterval,
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tagSeparator: conf.TagSeparator,
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logger: logger,
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oldSourceList: make(map[string]bool),
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}
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return cd, nil
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}
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func main() {
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a.HelpFlag.Short('h')
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_, err := a.Parse(os.Args[1:])
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if err != nil {
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fmt.Println("err: ", err)
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return
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}
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logger = log.NewSyncLogger(log.NewLogfmtLogger(os.Stdout))
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logger = log.With(logger, "ts", log.DefaultTimestampUTC, "caller", log.DefaultCaller)
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ctx := context.Background()
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// NOTE: create an instance of your new SD implementation here.
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cfg := sdConfig{
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TagSeparator: ",",
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Address: *listenAddress,
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RefreshInterval: 30,
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}
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disc, err := newDiscovery(cfg)
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if err != nil {
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fmt.Println("err: ", err)
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}
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if err != nil {
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level.Error(logger).Log("msg", "failed to create discovery metrics", "err", err)
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os.Exit(1)
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}
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sdAdapter := adapter.NewAdapter(ctx, *outputFile, "exampleSD", disc, logger)
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sdAdapter.Run()
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<-ctx.Done()
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}
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