Interface update, per-method Contexts.

service/taskqueue/interface.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 taskqueue
 
-// Interface is the full interface to the Task Queue service.
-type Interface interface {
-        Add(task *Task, queueName string) error
-        Delete(task *Task, queueName string) error
+import (
+        "github.com/luci/luci-go/common/errors"
 
-        AddMulti(tasks []*Task, queueName string) error
-        DeleteMulti(tasks []*Task, queueName string) error
+        "golang.org/x/net/context"
+)
 
-        // NOTE(riannucci): No support for pull taskqueues. We're not planning on
-        // making pull-queue clients which RUN in appengine (e.g. they'd all be
-        // external REST consumers). If someone needs this, it will need to be added
-        // here and in RawInterface. The theory is that a good lease API might look
-        // like:
-        //
-        //   func Lease(queueName, tag string, batchSize int, duration time.Time, cb func(*Task, error<-))
-        //
-        // Which blocks and calls cb for each task obtained. Lease would then do all
-        // necessary backoff negotiation with the backend. The callback could execute
-        // synchronously (stuffing an error into the chan or panicing if it fails), or
-        // asynchronously (dispatching a goroutine which will then populate the error
-        // channel if needed). If it operates asynchronously, it has the option of
-        // processing multiple work items at a time.
-        //
-        // Lease would also take care of calling ModifyLease as necessary to ensure
-        // that each call to cb would have 'duration' amount of time to work on the
-        // task, as well as releasing as many leased tasks as it can on a failure.
+// Add adds the specified task(s) to the specified task queue.
+//
+// If only one task is provided its error will be returned directly. If more
+// than one task is provided, an errors.MultiError will be returned in the
+// event of an error, with a given error index corresponding to the error
+// encountered when processing the task at that index.
+func Add(c context.Context, queueName string, tasks ...*Task) error {
+        lme := errors.NewLazyMultiError(len(tasks))
+        i := 0
+        err := Raw(c).AddMulti(tasks, queueName, func(t *Task, err error) {
+                if !lme.Assign(i, err) {
+                        *tasks[i] = *t
+                }
+                i++
+        })
+        if err == nil {
+                err = lme.Get()
+                if len(tasks) == 1 {
+                        err = errors.SingleError(err)
+                }
+        }
+        return err
+}
 
-        Purge(queueName string) error
+// Delete deletes a task from the task queue.
+//
+// If only one task is provided its error will be returned directly. If more
+// than one task is provided, an errors.MultiError will be returned in the
+// event of an error, with a given error index corresponding to the error
+// encountered when processing the task at that index.
+func Delete(c context.Context, queueName string, tasks ...*Task) error {
+        lme := errors.NewLazyMultiError(len(tasks))
+        i := 0
+        err := Raw(c).DeleteMulti(tasks, queueName, func(err error) {
+                lme.Assign(i, err)
+                i++
+        })
+        if err == nil {
+                err = lme.Get()
+                if len(tasks) == 1 {
+                        err = errors.SingleError(err)
+                }
+        }
+        return err
+}
 
-        Stats(queueNames ...string) ([]Statistics, error)
+// NOTE(riannucci): No support for pull taskqueues. We're not planning on
+// making pull-queue clients which RUN in appengine (e.g. they'd all be
+// external REST consumers). If someone needs this, it will need to be added
+// here and in RawInterface. The theory is that a good lease API might look
+// like:
+//
+//   func Lease(queueName, tag string, batchSize int, duration time.Time, cb func(*Task, error<-))
+//
+// Which blocks and calls cb for each task obtained. Lease would then do all
+// necessary backoff negotiation with the backend. The callback could execute
+// synchronously (stuffing an error into the chan or panicing if it fails), or
+// asynchronously (dispatching a goroutine which will then populate the error
+// channel if needed). If it operates asynchronously, it has the option of
+// processing multiple work items at a time.
+//
+// Lease would also take care of calling ModifyLease as necessary to ensure
+// that each call to cb would have 'duration' amount of time to work on the
+// task, as well as releasing as many leased tasks as it can on a failure.
 
-        Testable() Testable
+// Purge purges all tasks form the named queue.
+func Purge(c context.Context, queueName string) error {
+        return Raw(c).Purge(queueName)
+}
 
-        Raw() RawInterface
+// Stats returns Statistics instances for each of the named task queues.
+//
+// If only one task is provided its error will be returned directly. If more
+// than one task is provided, an errors.MultiError will be returned in the
+// event of an error, with a given error index corresponding to the error
+// encountered when processing the task at that index.
+func Stats(c context.Context, queueNames ...string) ([]Statistics, error) {
+        ret := make([]Statistics, len(queueNames))
+        lme := errors.NewLazyMultiError(len(queueNames))
+        i := 0
+        err := Raw(c).Stats(queueNames, func(s *Statistics, err error) {
+                if !lme.Assign(i, err) {
+                        ret[i] = *s
+                }
+                i++
+        })
+        if err == nil {
+                err = lme.Get()
+                if len(queueNames) == 1 {
+                        err = errors.SingleError(err)
+                }
+        }
+        return ret, err
 }
+
+// GetTestable returns a Testable for the current task queue service in c, or
+// nil if it does not offer one.
+func GetTestable(c context.Context) Testable {
+        return Raw(c).GetTestable()
+}