envoyproxy/envoy

[test] Remove use of temporary files in test environment

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#15,362 opened on Mar 8, 2021

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Description

Remove real temporary files in test environment

Description: Using real filesystems when running blaze test and creating temporary paths is non-hermetic. I've also seen a number of flakes in end to end fuzzers that extend BaseIntegrationTest and are failing on illegalPath, likely because of a space of other issue accessing the file. Ideally, running test binaries should not create files.

The major use of filepaths is using the bootstrap config path https://github.com/envoyproxy/envoy/blob/36e05482cc27b4d2b5765fdebcdb5fef16f07d84/test/integration/base_integration_test.cc#L191-L192 but there are also use cases for

  • File access logs, Tap paths, profile paths
  • xDS paths
  • Direct responses

The bootstrap config can be loaded via a string, but not all of the above use-cases have inline string replacements.

Perhaps we can instantiate a virtual filesystem in memory when running in certain modes/for certain tests. https://github.com/envoyproxy/envoy/blob/main/test/test_common/environment.h

See https://github.com/envoyproxy/envoy/pull/15318

Contributor guide

Research direction
Investigate existing in memory virtual filesystem implementations in Envoy or C++ testing frameworks (e.g., GTest) that can replace temporary file usage in test environment, focusing on bootstrap config, file access/logs, xDS paths, and direct responses. Evaluate how to load bootstrap config from a string and adapt other file based use cases to use virtual paths.
Tech stack
cpp
Domain
testing
Issue type
Refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Envoy test infrastructurefilesystem concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40