[
https://issues.apache.org/jira/browse/BEAM-7980?focusedWorklogId=299132&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-299132
]
ASF GitHub Bot logged work on BEAM-7980:
----------------------------------------
Author: ASF GitHub Bot
Created on: 22/Aug/19 03:28
Start Date: 22/Aug/19 03:28
Worklog Time Spent: 10m
Work Description: tweise commented on pull request #9398: [BEAM-7980]
Exactly once artifact retrieval for Python SDK worker pool
URL: https://github.com/apache/beam/pull/9398#discussion_r316483610
##########
File path: sdks/python/container/boot.go
##########
@@ -105,18 +107,57 @@ func main() {
// (2) Retrieve and install the staged packages.
- dir := filepath.Join(*semiPersistDir, "staged")
+ func() {
- files, err := artifact.Materialize(ctx, *artifactEndpoint,
info.GetRetrievalToken(), dir)
- if err != nil {
- log.Fatalf("Failed to retrieve staged files: %v", err)
- }
+ installCompleteFile := filepath.Join(os.TempDir(),
"beam.install.complete")
- // TODO(herohde): the packages to install should be specified
explicitly. It
- // would also be possible to install the SDK in the Dockerfile.
- if setupErr := installSetupPackages(files, dir); setupErr != nil {
- log.Fatalf("Failed to install required packages: %v", setupErr)
- }
+ // skip if install already complete
+ _, err = os.Stat(installCompleteFile)
+ if err == nil {
+ return
+ }
+
+ // lock to guard from concurrent artifact retrieval and
installation,
+ // when called by child processes in a worker pool
+ lock, err := lockfile.New(filepath.Join(os.TempDir(),
"beam.install.lck"))
+ if err != nil {
+ log.Fatalf("Cannot init artifact retrieval lock: %v",
err)
+ }
+
+ for err = lock.TryLock(); err != nil; err = lock.TryLock() {
+ switch err {
+ case lockfile.ErrBusy, lockfile.ErrNotExist:
+ time.Sleep(5 * time.Second)
+ log.Printf("Worker %v waiting for artifact
retrieval lock: %v", *id, lock)
+ default:
+ log.Fatalf("Worker %v could not obtain artifact
retrieval lock: %v", *id, err)
+ }
+ }
+ defer lock.Unlock()
+
+ // skip if install already complete
+ _, err = os.Stat(installCompleteFile)
+ if err == nil {
+ return
+ }
+
+ dir := filepath.Join(*semiPersistDir, "staged")
+
+ files, err := artifact.Materialize(ctx, *artifactEndpoint,
info.GetRetrievalToken(), dir)
+ if err != nil {
+ log.Fatalf("Failed to retrieve staged files: %v", err)
+ }
+
+ // TODO(herohde): the packages to install should be specified
explicitly. It
+ // would also be possible to install the SDK in the Dockerfile.
+ if setupErr := installSetupPackages(files, dir); setupErr !=
nil {
Review comment:
In the future we could look into inverting this logic by extracting the
exactly-once logic into a separate function that can be shared between the SDK
containers.
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Issue Time Tracking
-------------------
Worklog Id: (was: 299132)
Time Spent: 5.5h (was: 5h 20m)
> External environment with containerized worker pool
> ---------------------------------------------------
>
> Key: BEAM-7980
> URL: https://issues.apache.org/jira/browse/BEAM-7980
> Project: Beam
> Issue Type: Improvement
> Components: sdk-py-harness
> Reporter: Thomas Weise
> Assignee: Thomas Weise
> Priority: Major
> Time Spent: 5.5h
> Remaining Estimate: 0h
>
> Augment Beam Python docker image and boot.go so that it can be used to launch
> BeamFnExternalWorkerPoolServicer.
> [https://docs.google.com/document/d/1z3LNrRtr8kkiFHonZ5JJM_L4NWNBBNcqRc_yAf6G0VI/edit#heading=h.lnhm75dhvhi0]
>
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