13025: Add request time metrics at /metrics and /metrics.json.

[arvados.git] / services / keepstore / pull_worker.go

diff --git a/services/keepstore/pull_worker.go b/services/keepstore/pull_worker.go
index 150b5ca2349a6e2765099feb39abc1a3f90ebedd..42b5d5889d30984685d43655f66fb3857f98de92 100644 (file)
--- 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 != "" {