Handle TOCTOU in azure objstorage add()
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Authored by olasd on May 15 2020, 10:30 AM.

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ardumont

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Reviewers

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rDOBJSd61fd8afc612: Handle TOCTOU in azure objstorage add()

Summary

There's an unavoidable race condition in the azure objstorage between the
existence check and upload. When this race condition happens and we upload the
same blob twice, one of the uploads is rejected with a ResourceExistsError.

This change brings the azure objstorage back to idempotence.

Fixes sentry error SWH-STORAGE-G6.

Test Plan

new tox test added, adding the same object twice (and forcing the
ResourceExistsError).

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rDOBJS Object storage

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master

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Buildable 12397
Build 18808: Phabricator diff pipeline on jenkins	Jenkins console · Jenkins
Build 18807: arc lint + arc unit

Event Timeline

olasd created this revision.May 15 2020, 10:30 AM

Herald added a reviewer: Reviewers. · View Herald TranscriptMay 15 2020, 10:30 AM

Build is green

Patch application report for D3155 (id=11209)

Rebasing onto f485201c26...

Current branch diff-target is up to date.

Changes applied before test

commit d61fd8afc61226d5471da5dbcfcd95da093fc283
Author: Nicolas Dandrimont <nicolas@dandrimont.eu>
Date:   Fri May 15 10:27:06 2020 +0200

    Handle TOCTOU in azure objstorage add()
    
    There's an unavoidable race condition in the azure objstorage between the
    existence check and upload. When this race condition happens and we upload the
    same blob twice, one of the uploads is rejected with a `ResourceExistsError`.
    
    This change brings the azure objstorage back to idempotence.
    
    Fixes sentry error SWH-STORAGE-G6.

See https://jenkins.softwareheritage.org/job/DOBJS/job/tests-on-diff/10/ for more details.

Harbormaster completed remote builds in B12397: Diff 11209.May 15 2020, 10:32 AM

ardumont accepted this revision.May 15 2020, 10:34 AM

This revision is now accepted and ready to land.May 15 2020, 10:34 AM

Closed by commit rDOBJSd61fd8afc612: Handle TOCTOU in azure objstorage add() (authored by olasd). · Explain WhyMay 15 2020, 10:34 AM

This revision was automatically updated to reflect the committed changes.

olasd added a commit: rDOBJSd61fd8afc612: Handle TOCTOU in azure objstorage add().