117 lines
3 KiB
Go
117 lines
3 KiB
Go
// Package discover provides functions to get metadata for different
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// cloud environments.
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package discover
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import (
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"fmt"
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"log"
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"sort"
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"strings"
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"sync"
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"github.com/hashicorp/go-discover/provider/aws"
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"github.com/hashicorp/go-discover/provider/azure"
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"github.com/hashicorp/go-discover/provider/gce"
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"github.com/hashicorp/go-discover/provider/softlayer"
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)
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// Provider has lookup functions for meta data in a
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// cloud environment.
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type Provider interface {
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// Addrs looks up addresses in the cloud environment according to the
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// configuration provided in args.
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Addrs(args map[string]string, l *log.Logger) ([]string, error)
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// Help provides the configuration help for the command line client.
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Help() string
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}
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// Providers contains all available providers.
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var Providers = map[string]Provider{
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"aws": &aws.Provider{},
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"azure": &azure.Provider{},
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"gce": &gce.Provider{},
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"softlayer": &softlayer.Provider{},
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}
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// Discover looks up metadata in different cloud environments.
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type Discover struct {
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// Providers is the list of address lookup providers.
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// If nil, the default list of providers is used.
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Providers map[string]Provider
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// once is used to initialize the actual list of providers.
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once sync.Once
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}
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// initProviders sets the list of providers to the
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// default list of providers if none are configured.
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func (d *Discover) initProviders() {
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if d.Providers == nil {
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d.Providers = Providers
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}
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}
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// Names returns the names of the configured providers.
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func (d *Discover) Names() []string {
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d.once.Do(d.initProviders)
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var names []string
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for n := range d.Providers {
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names = append(names, n)
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}
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sort.Strings(names)
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return names
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}
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var globalHelp = `The options for discovering ip addresses are provided as a
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single string value in "key=value key=value ..." format where
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the values are URL encoded.
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provider=aws region=eu-west-1 ...
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The options are provider specific and are listed below.
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`
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// Help describes the format of the configuration string for address discovery
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// and the various provider specific options.
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func (d *Discover) Help() string {
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d.once.Do(d.initProviders)
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h := []string{globalHelp}
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for _, name := range d.Names() {
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h = append(h, d.Providers[name].Help())
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}
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return strings.Join(h, "\n")
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}
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// Addrs discovers ip addresses of nodes that match the given filter criteria.
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// The config string must have the format 'provider=xxx key=val key=val ...'
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// where the keys and values are provider specific. The values are URL encoded.
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func (d *Discover) Addrs(cfg string, l *log.Logger) ([]string, error) {
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d.once.Do(d.initProviders)
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args, err := Parse(cfg)
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if err != nil {
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return nil, fmt.Errorf("discover: %s", err)
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}
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name := args["provider"]
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if name == "" {
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return nil, fmt.Errorf("discover: no provider")
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}
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providers := d.Providers
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if providers == nil {
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providers = Providers
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}
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p := providers[name]
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if p == nil {
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return nil, fmt.Errorf("discover: unknown provider " + name)
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}
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l.Printf("[DEBUG] discover: Using provider %q", name)
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return p.Addrs(args, l)
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}
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