open-consul/watch/funcs.go

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package watch
import (
"fmt"
"github.com/armon/consul-api"
)
// 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{}) (WatchFunc, error)
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// watchFuncFactory maps each type to a factory function
var watchFuncFactory map[string]watchFactory
func init() {
watchFuncFactory = map[string]watchFactory{
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"key": keyWatch,
"keyprefix": keyPrefixWatch,
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"services": servicesWatch,
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"nodes": nodesWatch,
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"service": serviceWatch,
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"checks": checksWatch,
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"event": eventWatch,
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}
}
// keyWatch is used to return a key watching function
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func keyWatch(params map[string]interface{}) (WatchFunc, error) {
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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 *WatchPlan) (uint64, interface{}, error) {
kv := p.client.KV()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
pair, meta, err := kv.Get(key, &opts)
if err != nil {
return 0, nil, err
}
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if pair == nil {
return meta.LastIndex, nil, err
}
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return meta.LastIndex, pair, err
}
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{}) (WatchFunc, error) {
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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 *WatchPlan) (uint64, interface{}, error) {
kv := p.client.KV()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
pairs, meta, err := kv.List(prefix, &opts)
if err != nil {
return 0, nil, err
}
return meta.LastIndex, pairs, err
}
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{}) (WatchFunc, error) {
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fn := func(p *WatchPlan) (uint64, interface{}, error) {
catalog := p.client.Catalog()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
services, meta, err := catalog.Services(&opts)
if err != nil {
return 0, nil, err
}
return meta.LastIndex, services, err
}
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{}) (WatchFunc, error) {
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fn := func(p *WatchPlan) (uint64, interface{}, error) {
catalog := p.client.Catalog()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
nodes, meta, err := catalog.Nodes(&opts)
if err != nil {
return 0, nil, err
}
return meta.LastIndex, nodes, err
}
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{}) (WatchFunc, error) {
var service, tag 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 := assignValue(params, "tag", &tag); err != nil {
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 *WatchPlan) (uint64, interface{}, error) {
health := p.client.Health()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
nodes, meta, err := health.Service(service, tag, passingOnly, &opts)
if err != nil {
return 0, nil, err
}
return meta.LastIndex, nodes, err
}
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{}) (WatchFunc, error) {
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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 *WatchPlan) (uint64, interface{}, error) {
health := p.client.Health()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
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 0, nil, err
}
return meta.LastIndex, checks, err
}
return fn, nil
}
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// eventWatch is used to watch for events, optionally filtering on name
func eventWatch(params map[string]interface{}) (WatchFunc, error) {
var name string
if err := assignValue(params, "name", &name); err != nil {
return nil, err
}
fn := func(p *WatchPlan) (uint64, interface{}, error) {
event := p.client.Event()
opts := consulapi.QueryOptions{WaitIndex: p.lastIndex}
events, meta, err := event.List(name, &opts)
if err != nil {
return 0, nil, err
}
// Prune to only the new events
for i := 0; i < len(events); i++ {
if event.IDToIndex(events[i].ID) == p.lastIndex {
events = events[i+1:]
break
}
}
return meta.LastIndex, events, err
}
return fn, nil
}