118 lines
3.7 KiB
Go
118 lines
3.7 KiB
Go
// Copyright 2020 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 discovery
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import (
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"context"
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"reflect"
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"github.com/go-kit/log"
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"github.com/prometheus/common/config"
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"github.com/prometheus/prometheus/discovery/targetgroup"
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)
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// Discoverer provides information about target groups. It maintains a set
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// of sources from which TargetGroups can originate. Whenever a discovery provider
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// detects a potential change, it sends the TargetGroup through its channel.
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//
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// Discoverer does not know if an actual change happened.
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// It does guarantee that it sends the new TargetGroup whenever a change happens.
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//
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// Discoverers should initially send a full set of all discoverable TargetGroups.
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type Discoverer interface {
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// Run hands a channel to the discovery provider (Consul, DNS, etc.) through which
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// it can send updated target groups. It must return when the context is canceled.
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// It should not close the update channel on returning.
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Run(ctx context.Context, up chan<- []*targetgroup.Group)
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}
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// DiscovererOptions provides options for a Discoverer.
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type DiscovererOptions struct {
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Logger log.Logger
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}
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// A Config provides the configuration and constructor for a Discoverer.
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type Config interface {
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// Name returns the name of the discovery mechanism.
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Name() string
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// NewDiscoverer returns a Discoverer for the Config
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// with the given DiscovererOptions.
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NewDiscoverer(DiscovererOptions) (Discoverer, error)
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}
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// Configs is a slice of Config values that uses custom YAML marshaling and unmarshaling
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// to represent itself as a mapping of the Config values grouped by their types.
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type Configs []Config
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// SetDirectory joins any relative file paths with dir.
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func (c *Configs) SetDirectory(dir string) {
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for _, c := range *c {
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if v, ok := c.(config.DirectorySetter); ok {
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v.SetDirectory(dir)
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}
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}
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}
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// UnmarshalYAML implements yaml.Unmarshaler.
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func (c *Configs) UnmarshalYAML(unmarshal func(interface{}) error) error {
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cfgTyp := getConfigType(configsType)
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cfgPtr := reflect.New(cfgTyp)
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cfgVal := cfgPtr.Elem()
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if err := unmarshal(cfgPtr.Interface()); err != nil {
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return replaceYAMLTypeError(err, cfgTyp, configsType)
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}
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var err error
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*c, err = readConfigs(cfgVal, 0)
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return err
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}
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// MarshalYAML implements yaml.Marshaler.
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func (c Configs) MarshalYAML() (interface{}, error) {
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cfgTyp := getConfigType(configsType)
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cfgPtr := reflect.New(cfgTyp)
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cfgVal := cfgPtr.Elem()
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if err := writeConfigs(cfgVal, c); err != nil {
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return nil, err
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}
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return cfgPtr.Interface(), nil
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}
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// A StaticConfig is a Config that provides a static list of targets.
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type StaticConfig []*targetgroup.Group
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// Name returns the name of the service discovery mechanism.
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func (StaticConfig) Name() string { return "static" }
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// NewDiscoverer returns a Discoverer for the Config.
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func (c StaticConfig) NewDiscoverer(DiscovererOptions) (Discoverer, error) {
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return staticDiscoverer(c), nil
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}
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type staticDiscoverer []*targetgroup.Group
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func (c staticDiscoverer) Run(ctx context.Context, up chan<- []*targetgroup.Group) {
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// TODO: existing implementation closes up chan, but documentation explicitly forbids it...?
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defer close(up)
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select {
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case <-ctx.Done():
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case up <- c:
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}
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}
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