open-consul/api/watch/funcs.go

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package watch
import (
"context"
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"fmt"
consulapi "github.com/hashicorp/consul/api"
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)
// watchFactory is a function that can create a new WatchFunc
// from a parameter configuration
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type watchFactory func(params map[string]interface{}) (WatcherFunc, error)
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// watchFuncFactory maps each type to a factory function
var watchFuncFactory map[string]watchFactory
func init() {
watchFuncFactory = map[string]watchFactory{
"key": keyWatch,
"keyprefix": keyPrefixWatch,
"services": servicesWatch,
"nodes": nodesWatch,
"service": serviceWatch,
"checks": checksWatch,
"event": eventWatch,
"connect_roots": connectRootsWatch,
"connect_leaf": connectLeafWatch,
"agent_service": agentServiceWatch,
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}
}
// keyWatch is used to return a key watching function
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func keyWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
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var key string
if err := assignValue(params, "key", &key); err != nil {
return nil, err
}
if key == "" {
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return nil, fmt.Errorf("Must specify a single key to watch")
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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kv := p.client.KV()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
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pair, meta, err := kv.Get(key, &opts)
if err != nil {
return nil, nil, err
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}
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if pair == nil {
return WaitIndexVal(meta.LastIndex), nil, err
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}
return WaitIndexVal(meta.LastIndex), pair, err
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}
return fn, nil
}
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// keyPrefixWatch is used to return a key prefix watching function
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func keyPrefixWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
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var prefix string
if err := assignValue(params, "prefix", &prefix); err != nil {
return nil, err
}
if prefix == "" {
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return nil, fmt.Errorf("Must specify a single prefix to watch")
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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kv := p.client.KV()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
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pairs, meta, err := kv.List(prefix, &opts)
if err != nil {
return nil, nil, err
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}
return WaitIndexVal(meta.LastIndex), pairs, err
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}
return fn, nil
}
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// servicesWatch is used to watch the list of available services
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func servicesWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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catalog := p.client.Catalog()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
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services, meta, err := catalog.Services(&opts)
if err != nil {
return nil, nil, err
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}
return WaitIndexVal(meta.LastIndex), services, err
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}
return fn, nil
}
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// nodesWatch is used to watch the list of available nodes
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func nodesWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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catalog := p.client.Catalog()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
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nodes, meta, err := catalog.Nodes(&opts)
if err != nil {
return nil, nil, err
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}
return WaitIndexVal(meta.LastIndex), nodes, err
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}
return fn, nil
}
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// serviceWatch is used to watch a specific service for changes
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func serviceWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
var (
service string
tags []string
)
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if err := assignValue(params, "service", &service); err != nil {
return nil, err
}
if service == "" {
return nil, fmt.Errorf("Must specify a single service to watch")
}
if err := assignValueStringSlice(params, "tag", &tags); err != nil {
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return nil, err
}
passingOnly := false
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if err := assignValueBool(params, "passingonly", &passingOnly); err != nil {
return nil, err
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}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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health := p.client.Health()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
nodes, meta, err := health.ServiceMultipleTags(service, tags, passingOnly, &opts)
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if err != nil {
return nil, nil, err
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}
return WaitIndexVal(meta.LastIndex), nodes, err
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}
return fn, nil
}
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// checksWatch is used to watch a specific checks in a given state
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func checksWatch(params map[string]interface{}) (WatcherFunc, error) {
stale := false
if err := assignValueBool(params, "stale", &stale); err != nil {
return nil, err
}
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var service, state string
if err := assignValue(params, "service", &service); err != nil {
return nil, err
}
if err := assignValue(params, "state", &state); err != nil {
return nil, err
}
if service != "" && state != "" {
return nil, fmt.Errorf("Cannot specify service and state")
}
if service == "" && state == "" {
state = "any"
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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health := p.client.Health()
opts := makeQueryOptionsWithContext(p, stale)
defer p.cancelFunc()
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var checks []*consulapi.HealthCheck
var meta *consulapi.QueryMeta
var err error
if state != "" {
checks, meta, err = health.State(state, &opts)
} else {
checks, meta, err = health.Checks(service, &opts)
}
if err != nil {
return nil, nil, err
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}
return WaitIndexVal(meta.LastIndex), checks, err
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}
return fn, nil
}
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// eventWatch is used to watch for events, optionally filtering on name
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func eventWatch(params map[string]interface{}) (WatcherFunc, error) {
// The stale setting doesn't apply to events.
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var name string
if err := assignValue(params, "name", &name); err != nil {
return nil, err
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
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event := p.client.Event()
opts := makeQueryOptionsWithContext(p, false)
defer p.cancelFunc()
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events, meta, err := event.List(name, &opts)
if err != nil {
return nil, nil, err
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}
// Prune to only the new events
for i := 0; i < len(events); i++ {
if WaitIndexVal(event.IDToIndex(events[i].ID)).Equal(p.lastParamVal) {
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events = events[i+1:]
break
}
}
return WaitIndexVal(meta.LastIndex), events, err
}
return fn, nil
}
// connectRootsWatch is used to watch for changes to Connect Root certificates.
func connectRootsWatch(params map[string]interface{}) (WatcherFunc, error) {
// We don't support stale since roots are cached locally in the agent.
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
agent := p.client.Agent()
opts := makeQueryOptionsWithContext(p, false)
defer p.cancelFunc()
roots, meta, err := agent.ConnectCARoots(&opts)
if err != nil {
return nil, nil, err
}
return WaitIndexVal(meta.LastIndex), roots, err
}
return fn, nil
}
// connectLeafWatch is used to watch for changes to Connect Leaf certificates
// for given local service id.
func connectLeafWatch(params map[string]interface{}) (WatcherFunc, error) {
// We don't support stale since certs are cached locally in the agent.
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var serviceName string
if err := assignValue(params, "service", &serviceName); err != nil {
return nil, err
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
agent := p.client.Agent()
opts := makeQueryOptionsWithContext(p, false)
defer p.cancelFunc()
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leaf, meta, err := agent.ConnectCALeaf(serviceName, &opts)
if err != nil {
return nil, nil, err
}
return WaitIndexVal(meta.LastIndex), leaf, err
}
return fn, nil
}
// agentServiceWatch is used to watch for changes to a single service instance
// on the local agent. Note that this state is agent-local so the watch
// mechanism uses `hash` rather than `index` for deciding whether to block.
func agentServiceWatch(params map[string]interface{}) (WatcherFunc, error) {
// We don't support consistency modes since it's agent local data
var serviceID string
if err := assignValue(params, "service_id", &serviceID); err != nil {
return nil, err
}
fn := func(p *Plan) (BlockingParamVal, interface{}, error) {
agent := p.client.Agent()
opts := makeQueryOptionsWithContext(p, false)
defer p.cancelFunc()
svc, _, err := agent.Service(serviceID, &opts)
if err != nil {
return nil, nil, err
}
// Return string ContentHash since we don't have Raft indexes to block on.
return WaitHashVal(svc.ContentHash), svc, err
}
return fn, nil
}
func makeQueryOptionsWithContext(p *Plan, stale bool) consulapi.QueryOptions {
ctx, cancel := context.WithCancel(context.Background())
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p.setCancelFunc(cancel)
opts := consulapi.QueryOptions{AllowStale: stale}
switch param := p.lastParamVal.(type) {
case WaitIndexVal:
opts.WaitIndex = uint64(param)
case WaitHashVal:
opts.WaitHash = string(param)
}
return *opts.WithContext(ctx)
}