fix: Race conditions with multiple downloads on the same layer #7422
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mndeveci
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Aug 30, 2024
mndeveci
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Aug 30, 2024
lucashuy
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Aug 30, 2024
| @@ -106,7 +107,7 @@ def download(self, layer: LayerVersion, force=False) -> LayerVersion: | |||
| LOG.info("%s is already cached. Skipping download", layer.arn) | |||
| return layer | |||
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|
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| layer_zip_path = layer.codeuri + ".zip" | |||
| layer_zip_path = f"{layer.codeuri}_{uuid.uuid4().hex}.zip" | |||
| layer_zip_uri = self._fetch_layer_uri(layer) | |||
| unzip_from_uri( | |||
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quick question, but will we come across any issues when the Layer is unpacked into the same directory across different threads? I would imagine that this would be fine since the OS controls I/O, but wanted to check
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Oh it should be fine. This is what we want :)
lucashuy
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Which issue(s) does this change fix?
Why is this change necessary?
Customer reports that when the SAM template contains multiple functions, some shared the same lambda layer,
local start-apithrow the exceptionThis is because there was a race condition when multiple layer_downloaders were running to build multiple functions concurrently. Some could finish downloading the file first and remove the .zip file, causing the other one failed to unzip.
How does it address the issue?
The fix is to ask each downloader to download into separate zip file (by adding the thread id to the file name), but the extracted folder remains the same.
What side effects does this change have?
Mandatory Checklist
PRs will only be reviewed after checklist is complete
make prpassesmake update-reproducible-reqsif dependencies were changedBy submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.