mirror of
https://github.com/prometheus/prometheus
synced 2024-12-25 16:02:28 +00:00
45506841e6
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
544 lines
17 KiB
Go
544 lines
17 KiB
Go
// Copyright 2015 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 consul
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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"strconv"
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"strings"
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"time"
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"github.com/go-kit/kit/log"
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"github.com/go-kit/kit/log/level"
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consul "github.com/hashicorp/consul/api"
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conntrack "github.com/mwitkow/go-conntrack"
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"github.com/pkg/errors"
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"github.com/prometheus/client_golang/prometheus"
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config_util "github.com/prometheus/common/config"
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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/util/strutil"
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)
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const (
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watchTimeout = 30 * time.Second
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retryInterval = 15 * time.Second
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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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// metaDataLabel is the prefix for the labels mapping to a target's metadata.
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metaDataLabel = model.MetaLabelPrefix + "consul_metadata_"
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// serviceMetaDataLabel is the prefix for the labels mapping to a target's service metadata.
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serviceMetaDataLabel = model.MetaLabelPrefix + "consul_service_metadata_"
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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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// serviceLabel is the name of the label containing the service name.
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serviceLabel = model.MetaLabelPrefix + "consul_service"
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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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// datacenterLabel is the name of the label containing the datacenter ID.
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datacenterLabel = model.MetaLabelPrefix + "consul_dc"
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// taggedAddressesLabel is the prefix for the labels mapping to a target's tagged addresses.
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taggedAddressesLabel = model.MetaLabelPrefix + "consul_tagged_address_"
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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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// Constants for instrumentation.
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namespace = "prometheus"
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)
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var (
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rpcFailuresCount = prometheus.NewCounter(
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prometheus.CounterOpts{
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Namespace: namespace,
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Name: "sd_consul_rpc_failures_total",
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Help: "The number of Consul RPC call failures.",
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})
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rpcDuration = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: namespace,
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Name: "sd_consul_rpc_duration_seconds",
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Help: "The duration of a Consul RPC call in seconds.",
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},
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[]string{"endpoint", "call"},
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)
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// DefaultSDConfig is the default Consul SD configuration.
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DefaultSDConfig = SDConfig{
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TagSeparator: ",",
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Scheme: "http",
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Server: "localhost:8500",
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AllowStale: true,
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RefreshInterval: model.Duration(watchTimeout),
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}
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)
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// SDConfig is the configuration for Consul service discovery.
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type SDConfig struct {
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Server string `yaml:"server,omitempty"`
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Token config_util.Secret `yaml:"token,omitempty"`
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Datacenter string `yaml:"datacenter,omitempty"`
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TagSeparator string `yaml:"tag_separator,omitempty"`
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Scheme string `yaml:"scheme,omitempty"`
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Username string `yaml:"username,omitempty"`
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Password config_util.Secret `yaml:"password,omitempty"`
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// See https://www.consul.io/docs/internals/consensus.html#consistency-modes,
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// stale reads are a lot cheaper and are a necessity if you have >5k targets.
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AllowStale bool `yaml:"allow_stale"`
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// By default use blocking queries (https://www.consul.io/api/index.html#blocking-queries)
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// but allow users to throttle updates if necessary. This can be useful because of "bugs" like
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// https://github.com/hashicorp/consul/issues/3712 which cause an un-necessary
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// amount of requests on consul.
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RefreshInterval model.Duration `yaml:"refresh_interval,omitempty"`
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// See https://www.consul.io/api/catalog.html#list-services
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// The list of services for which targets are discovered.
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// Defaults to all services if empty.
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Services []string `yaml:"services,omitempty"`
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// A list of tags used to filter instances inside a service. Services must contain all tags in the list.
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ServiceTags []string `yaml:"tags,omitempty"`
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// Desired node metadata.
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NodeMeta map[string]string `yaml:"node_meta,omitempty"`
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TLSConfig config_util.TLSConfig `yaml:"tls_config,omitempty"`
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}
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// UnmarshalYAML implements the yaml.Unmarshaler interface.
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func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
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*c = DefaultSDConfig
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type plain SDConfig
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err := unmarshal((*plain)(c))
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if err != nil {
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return err
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}
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if strings.TrimSpace(c.Server) == "" {
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return errors.New("consul SD configuration requires a server address")
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}
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return nil
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}
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func init() {
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prometheus.MustRegister(rpcFailuresCount)
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prometheus.MustRegister(rpcDuration)
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// Initialize metric vectors.
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rpcDuration.WithLabelValues("catalog", "service")
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rpcDuration.WithLabelValues("catalog", "services")
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}
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// Discovery retrieves target information from a Consul server
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// and updates them via watches.
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type Discovery struct {
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client *consul.Client
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clientDatacenter string
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tagSeparator string
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watchedServices []string // Set of services which will be discovered.
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watchedTags []string // Tags used to filter instances of a service.
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watchedNodeMeta map[string]string
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allowStale bool
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refreshInterval time.Duration
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finalizer func()
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logger log.Logger
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}
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// NewDiscovery returns a new Discovery for the given config.
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func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
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if logger == nil {
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logger = log.NewNopLogger()
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}
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tls, err := config_util.NewTLSConfig(&conf.TLSConfig)
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if err != nil {
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return nil, err
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}
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transport := &http.Transport{
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IdleConnTimeout: 5 * time.Duration(conf.RefreshInterval),
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TLSClientConfig: tls,
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DialContext: conntrack.NewDialContextFunc(
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conntrack.DialWithTracing(),
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conntrack.DialWithName("consul_sd"),
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),
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}
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wrapper := &http.Client{
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Transport: transport,
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Timeout: 35 * time.Second,
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}
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clientConf := &consul.Config{
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Address: conf.Server,
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Scheme: conf.Scheme,
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Datacenter: conf.Datacenter,
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Token: string(conf.Token),
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HttpAuth: &consul.HttpBasicAuth{
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Username: conf.Username,
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Password: string(conf.Password),
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},
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HttpClient: wrapper,
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}
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client, err := consul.NewClient(clientConf)
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if err != nil {
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return nil, err
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}
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cd := &Discovery{
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client: client,
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tagSeparator: conf.TagSeparator,
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watchedServices: conf.Services,
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watchedTags: conf.ServiceTags,
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watchedNodeMeta: conf.NodeMeta,
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allowStale: conf.AllowStale,
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refreshInterval: time.Duration(conf.RefreshInterval),
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clientDatacenter: conf.Datacenter,
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finalizer: transport.CloseIdleConnections,
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logger: logger,
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}
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return cd, nil
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}
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// shouldWatch returns whether the service of the given name should be watched.
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func (d *Discovery) shouldWatch(name string, tags []string) bool {
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return d.shouldWatchFromName(name) && d.shouldWatchFromTags(tags)
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}
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// shouldWatch returns whether the service of the given name should be watched based on its name.
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func (d *Discovery) shouldWatchFromName(name string) bool {
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// If there's no fixed set of watched services, we watch everything.
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if len(d.watchedServices) == 0 {
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return true
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}
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for _, sn := range d.watchedServices {
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if sn == name {
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return true
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}
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}
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return false
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}
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// shouldWatch returns whether the service of the given name should be watched based on its tags.
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// This gets called when the user doesn't specify a list of services in order to avoid watching
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// *all* services. Details in https://github.com/prometheus/prometheus/pull/3814
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func (d *Discovery) shouldWatchFromTags(tags []string) bool {
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// If there's no fixed set of watched tags, we watch everything.
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if len(d.watchedTags) == 0 {
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return true
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}
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tagOuter:
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for _, wtag := range d.watchedTags {
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for _, tag := range tags {
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if wtag == tag {
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continue tagOuter
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}
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}
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return false
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}
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return true
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}
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// Get the local datacenter if not specified.
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func (d *Discovery) getDatacenter() error {
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// If the datacenter was not set from clientConf, let's get it from the local Consul agent
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// (Consul default is to use local node's datacenter if one isn't given for a query).
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if d.clientDatacenter != "" {
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return nil
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}
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info, err := d.client.Agent().Self()
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if err != nil {
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level.Error(d.logger).Log("msg", "Error retrieving datacenter name", "err", err)
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rpcFailuresCount.Inc()
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return err
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}
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dc, ok := info["Config"]["Datacenter"].(string)
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if !ok {
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err := errors.Errorf("invalid value '%v' for Config.Datacenter", info["Config"]["Datacenter"])
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level.Error(d.logger).Log("msg", "Error retrieving datacenter name", "err", err)
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return err
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}
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d.clientDatacenter = dc
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return nil
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}
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// Initialize the Discoverer run.
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func (d *Discovery) initialize(ctx context.Context) {
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// Loop until we manage to get the local datacenter.
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for {
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// We have to check the context at least once. The checks during channel sends
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// do not guarantee that.
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select {
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case <-ctx.Done():
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return
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default:
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}
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// Get the local datacenter first, if necessary.
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err := d.getDatacenter()
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if err != nil {
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time.Sleep(retryInterval)
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continue
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}
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// We are good to go.
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return
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}
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}
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// Run implements the Discoverer interface.
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func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
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if d.finalizer != nil {
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defer d.finalizer()
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}
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d.initialize(ctx)
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if len(d.watchedServices) == 0 || len(d.watchedTags) != 0 {
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// We need to watch the catalog.
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ticker := time.NewTicker(d.refreshInterval)
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// Watched services and their cancellation functions.
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services := make(map[string]func())
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var lastIndex uint64
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for {
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select {
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case <-ctx.Done():
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ticker.Stop()
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return
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default:
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d.watchServices(ctx, ch, &lastIndex, services)
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<-ticker.C
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}
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}
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} else {
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// We only have fully defined services.
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for _, name := range d.watchedServices {
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d.watchService(ctx, ch, name)
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}
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<-ctx.Done()
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}
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}
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// Watch the catalog for new services we would like to watch. This is called only
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// when we don't know yet the names of the services and need to ask Consul the
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// entire list of services.
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func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.Group, lastIndex *uint64, services map[string]func()) {
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catalog := d.client.Catalog()
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level.Debug(d.logger).Log("msg", "Watching services", "tags", d.watchedTags)
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t0 := time.Now()
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opts := &consul.QueryOptions{
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WaitIndex: *lastIndex,
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WaitTime: watchTimeout,
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AllowStale: d.allowStale,
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NodeMeta: d.watchedNodeMeta,
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}
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srvs, meta, err := catalog.Services(opts.WithContext(ctx))
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elapsed := time.Since(t0)
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rpcDuration.WithLabelValues("catalog", "services").Observe(elapsed.Seconds())
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if err != nil {
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level.Error(d.logger).Log("msg", "Error refreshing service list", "err", err)
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rpcFailuresCount.Inc()
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time.Sleep(retryInterval)
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return
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}
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// If the index equals the previous one, the watch timed out with no update.
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if meta.LastIndex == *lastIndex {
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return
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}
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*lastIndex = meta.LastIndex
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// Check for new services.
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for name := range srvs {
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// catalog.Service() returns a map of service name to tags, we can use that to watch
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// only the services that have the tag we are looking for (if specified).
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// In the future consul will also support server side for service metadata.
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// https://github.com/hashicorp/consul/issues/1107
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if !d.shouldWatch(name, srvs[name]) {
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continue
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}
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if _, ok := services[name]; ok {
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continue // We are already watching the service.
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}
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wctx, cancel := context.WithCancel(ctx)
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d.watchService(wctx, ch, name)
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services[name] = cancel
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}
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// Check for removed services.
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for name, cancel := range services {
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if _, ok := srvs[name]; !ok {
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// Call the watch cancellation function.
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cancel()
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delete(services, name)
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// Send clearing target group.
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select {
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case <-ctx.Done():
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return
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case ch <- []*targetgroup.Group{{Source: name}}:
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}
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}
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}
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}
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// consulService contains data belonging to the same service.
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type consulService struct {
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name string
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tags []string
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labels model.LabelSet
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discovery *Discovery
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client *consul.Client
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tagSeparator string
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logger log.Logger
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}
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// Start watching a service.
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func (d *Discovery) watchService(ctx context.Context, ch chan<- []*targetgroup.Group, name string) {
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srv := &consulService{
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discovery: d,
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client: d.client,
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name: name,
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tags: d.watchedTags,
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labels: model.LabelSet{
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serviceLabel: model.LabelValue(name),
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datacenterLabel: model.LabelValue(d.clientDatacenter),
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},
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tagSeparator: d.tagSeparator,
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logger: d.logger,
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}
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go func() {
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ticker := time.NewTicker(d.refreshInterval)
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var lastIndex uint64
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catalog := srv.client.Catalog()
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for {
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select {
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case <-ctx.Done():
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ticker.Stop()
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return
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default:
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srv.watch(ctx, ch, catalog, &lastIndex)
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select {
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case <-ticker.C:
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case <-ctx.Done():
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}
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}
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}
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}()
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}
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// Get updates for a service.
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func (srv *consulService) watch(ctx context.Context, ch chan<- []*targetgroup.Group, catalog *consul.Catalog, lastIndex *uint64) {
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level.Debug(srv.logger).Log("msg", "Watching service", "service", srv.name, "tags", srv.tags)
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t0 := time.Now()
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opts := &consul.QueryOptions{
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WaitIndex: *lastIndex,
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WaitTime: watchTimeout,
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AllowStale: srv.discovery.allowStale,
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NodeMeta: srv.discovery.watchedNodeMeta,
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}
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nodes, meta, err := catalog.ServiceMultipleTags(srv.name, srv.tags, opts.WithContext(ctx))
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elapsed := time.Since(t0)
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rpcDuration.WithLabelValues("catalog", "service").Observe(elapsed.Seconds())
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// Check the context before in order to exit early.
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select {
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case <-ctx.Done():
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return
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default:
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// Continue.
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}
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if err != nil {
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level.Error(srv.logger).Log("msg", "Error refreshing service", "service", srv.name, "tags", srv.tags, "err", err)
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rpcFailuresCount.Inc()
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time.Sleep(retryInterval)
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return
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}
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// If the index equals the previous one, the watch timed out with no update.
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if meta.LastIndex == *lastIndex {
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return
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}
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*lastIndex = meta.LastIndex
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tgroup := targetgroup.Group{
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Source: srv.name,
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Labels: srv.labels,
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Targets: make([]model.LabelSet, 0, len(nodes)),
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}
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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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var tags = srv.tagSeparator + strings.Join(node.ServiceTags, srv.tagSeparator) + srv.tagSeparator
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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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labels := model.LabelSet{
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model.AddressLabel: model.LabelValue(addr),
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addressLabel: model.LabelValue(node.Address),
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nodeLabel: model.LabelValue(node.Node),
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tagsLabel: model.LabelValue(tags),
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serviceAddressLabel: model.LabelValue(node.ServiceAddress),
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servicePortLabel: model.LabelValue(strconv.Itoa(node.ServicePort)),
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serviceIDLabel: model.LabelValue(node.ServiceID),
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}
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|
|
// Add all key/value pairs from the node's metadata as their own labels.
|
|
for k, v := range node.NodeMeta {
|
|
name := strutil.SanitizeLabelName(k)
|
|
labels[metaDataLabel+model.LabelName(name)] = model.LabelValue(v)
|
|
}
|
|
|
|
// Add all key/value pairs from the service's metadata as their own labels.
|
|
for k, v := range node.ServiceMeta {
|
|
name := strutil.SanitizeLabelName(k)
|
|
labels[serviceMetaDataLabel+model.LabelName(name)] = model.LabelValue(v)
|
|
}
|
|
|
|
// Add all key/value pairs from the service's tagged addresses as their own labels.
|
|
for k, v := range node.TaggedAddresses {
|
|
name := strutil.SanitizeLabelName(k)
|
|
labels[taggedAddressesLabel+model.LabelName(name)] = model.LabelValue(v)
|
|
}
|
|
|
|
tgroup.Targets = append(tgroup.Targets, labels)
|
|
}
|
|
|
|
select {
|
|
case <-ctx.Done():
|
|
case ch <- []*targetgroup.Group{&tgroup}:
|
|
}
|
|
}
|