[errors] de-specialize Transient in favor of Tags.

server/settings/settings.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 // Package settings implements storage for infrequently changing global
 // settings.
 //
 // Settings are represented as (key, value) pairs, where value is JSON
 // serializable struct. Settings are cached internally in the process memory to
 // avoid hitting the storage all the time.
 package settings
 
 import (
         "encoding/json"
         "errors"
         "reflect"
         "sync"
         "time"
 
         "golang.org/x/net/context"
 
         "github.com/luci/luci-go/common/clock"
         "github.com/luci/luci-go/common/data/caching/lazyslot"
         "github.com/luci/luci-go/common/logging"
         "github.com/luci/luci-go/common/retry"
+        "github.com/luci/luci-go/common/retry/transient"
 )
 
 var (
         // ErrNoSettings can be returned by Get and Set on fatal errors.
         ErrNoSettings = errors.New("settings: settings are not available")
 
         // ErrBadType is returned if Get(...) receives unexpected type.
         ErrBadType = errors.New("settings: bad type")
 )
 
@@ skipping 88 matching lines @@
 }
 
 // New creates new Settings object that uses given Storage to fetch and save
 // settings.
 func New(storage Storage) *Settings {
         return &Settings{
                 storage: storage,
                 values: lazyslot.Slot{
                         Timeout: 15 * time.Second, // retry for 15 sec at most
                         Fetcher: func(c context.Context, _ lazyslot.Value) (result lazyslot.Value, err error) {
-                                err = retry.Retry(c, retry.TransientOnly(retry.Default), func() error {
+                                err = retry.Retry(c, transient.Only(retry.Default), func() error {
                                         ctx, _ := clock.WithTimeout(c, 2*time.Second) // trigger a retry after 2 sec RPC timeout
                                         result, err = attemptToFetchSettings(ctx, storage)
                                         return err
                                 }, nil)
                                 if err != nil {
                                         result = lazyslot.Value{}
                                 }
                                 return
                         },
                 },
@@ skipping 77 matching lines @@
         }
 
         // Log the change. Ignore JSON marshaling errors, they are not essential
         // (and must not happen anyway).
         existingJSON, _ := json.Marshal(existing)
         modifiedJSON, _ := json.Marshal(value)
         logging.Warningf(c, "Settings %q changed from %s to %s by %q", key, existingJSON, modifiedJSON, who)
 
         return s.Set(c, key, value, who, why)
 }