X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/50c67a3eee468bcced060d5c868d243dcaff5837..163c8f8750193b791eb62f5a8d73dc44a006b69e:/services/keepstore/pull_worker.go

diff --git a/services/keepstore/pull_worker.go b/services/keepstore/pull_worker.go
index 150b5ca234..42b5d5889d 100644
--- a/services/keepstore/pull_worker.go
+++ b/services/keepstore/pull_worker.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
@@ -9,38 +13,32 @@ import (
 	"time"
 
 	"git.curoverse.com/arvados.git/sdk/go/keepclient"
-
-	log "github.com/Sirupsen/logrus"
 )
 
-// RunPullWorker is used by Keepstore to initiate pull worker channel goroutine.
-//	The channel will process pull list.
-//		For each (next) pull request:
-//			For each locator listed, execute Pull on the server(s) listed
-//			Skip the rest of the servers if no errors
-//		Repeat
-//
+// RunPullWorker receives PullRequests from pullq, invokes
+// PullItemAndProcess on each one. After each PR, it logs a message
+// indicating whether the pull was successful.
 func RunPullWorker(pullq *WorkQueue, keepClient *keepclient.KeepClient) {
-	nextItem := pullq.NextItem
-	for item := range nextItem {
-		pullRequest := item.(PullRequest)
-		err := PullItemAndProcess(item.(PullRequest), keepClient)
+	for item := range pullq.NextItem {
+		pr := item.(PullRequest)
+		err := PullItemAndProcess(pr, keepClient)
 		pullq.DoneItem <- struct{}{}
 		if err == nil {
-			log.Printf("Pull %s success", pullRequest)
+			log.Printf("Pull %s success", pr)
 		} else {
-			log.Printf("Pull %s error: %s", pullRequest, err)
+			log.Printf("Pull %s error: %s", pr, err)
 		}
 	}
 }
 
-// PullItemAndProcess pulls items from PullQueue and processes them.
-//	For each Pull request:
-//		Generate a random API token.
-//		Generate a permission signature using this token, timestamp ~60 seconds in the future, and desired block hash.
-//		Using this token & signature, retrieve the given block.
-//		Write to storage
+// PullItemAndProcess executes a pull request by retrieving the
+// specified block from one of the specified servers, and storing it
+// on a local volume.
 //
+// If the PR specifies a non-blank mount UUID, PullItemAndProcess will
+// only attempt to write the data to the corresponding
+// volume. Otherwise it writes to any local volume, as a PUT request
+// would.
 func PullItemAndProcess(pullRequest PullRequest, keepClient *keepclient.KeepClient) error {
 	var vol Volume
 	if uuid := pullRequest.MountUUID; uuid != "" {