100 lines
2.5 KiB
Go
100 lines
2.5 KiB
Go
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// Copyright © 2023 Roberto Hidalgo <event-gateway@un.rob.mx>
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// SPDX-License-Identifier: Apache-2.0
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package config
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import (
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// "fmt"
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// "os"
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// "os/signal"
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// "syscall"
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"context"
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"encoding/json"
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"fmt"
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"strings"
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"time"
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"git.rob.mx/nidito/chinampa/pkg/logger"
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"github.com/cenkalti/backoff"
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"github.com/hashicorp/consul/api"
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)
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var clogger = logger.Sub("event-gateway.config.consul")
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type Consul struct {
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Prefix string
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client *api.Client
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lastIndex uint64
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cancel context.CancelFunc
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registry chan []*Listener
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}
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func NewConsul(prefix string) (Loader, error) {
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cfg := api.DefaultConfig()
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client, err := api.NewClient(cfg)
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if err != nil {
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return nil, fmt.Errorf("could not initialize Consul configuration client loader: %s", err)
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}
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return &Consul{Prefix: prefix, client: client}, nil
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}
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var _ Loader = &Consul{}
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func (c *Consul) String() string {
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return fmt.Sprintf("ConsulLoader at %s", c.Prefix)
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}
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func (c *Consul) Load() (res []*Listener, err error) {
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opts := &api.QueryOptions{WaitIndex: c.lastIndex, WaitTime: 10 * time.Minute}
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clogger.Debugf("Querying kv at %s", c.Prefix)
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pairs, meta, err := c.client.KV().List(c.Prefix, opts)
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if err != nil {
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return res, fmt.Errorf("failed querying consul for config: %s", err)
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}
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clogger.Debugf("Querying ok: %+v, %d items found", meta.LastIndex, len(pairs))
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c.lastIndex = meta.LastIndex
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for _, p := range pairs {
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l := &Listener{ID: strings.TrimPrefix(p.Key, c.Prefix+"/")}
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clogger.Tracef("decoding config for %s", l.ID)
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if err := json.Unmarshal(p.Value, l); err != nil {
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return res, fmt.Errorf("could not decode config for %s/%s:%s", c.Prefix, p.Key, err)
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}
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clogger.Tracef("decoded config for %s", l.ID)
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res = append(res, l)
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}
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return res, nil
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}
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func (c *Consul) fetch() error {
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clogger.Info("Watch expired, reloading consul configuration")
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res, err := c.Load()
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if err != nil {
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return err
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}
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clogger.Info("Reloaded consul configuration")
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c.registry <- res
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return nil
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}
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func (c *Consul) Watch(reg chan []*Listener) {
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clogger.Infof("Starting config watch for %s", c.Prefix)
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bgctx, cancel := context.WithCancel(context.Background())
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c.cancel = cancel
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c.registry = reg
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ctx := backoff.WithContext(backoff.NewExponentialBackOff(), bgctx)
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onUpdateError := func(err error, cooldown time.Duration) {
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clogger.Errorf("%s. Retrying in %vs", err, cooldown.Truncate(time.Second))
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}
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go func() {
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for {
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if err := backoff.RetryNotify(c.fetch, ctx, onUpdateError); err != nil {
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continue
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}
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}
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}()
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}
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