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Utilize BucketObjectEntry in GC logic #8238

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Nov 7, 2024
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Utilize BucketObjectEntry in GC logic #8238

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65 changes: 31 additions & 34 deletions app/lib/package/api_export/exported_api.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ final _log = Logger('api_export:exported_bucket');
/// This ensures that we don't delete files we've just created.
/// It's entirely possible that one process is writing files, while another
/// process is running garbage collection.
const _minGarbageAge = Duration(days: 1);
const _minGarbageAge = Duration(hours: 3);
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@jonasfj jonasfj Nov 7, 2024

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This shouldn't be high, if something is published, it'll be at-least 3 hours before we can delete it.

I think that's perhaps somewhat reasonable. But we don't want this to be too high.

However, 3 hour should be more than enough for any eventual consistency issues between datastore and GCS to have been resolved.


/// Interface for [Bucket] containing exported API that is served directly from
/// Google Cloud Storage.
Expand Down Expand Up @@ -98,40 +98,37 @@ final class ExportedApi {
Future<void> _gcPrefix(String prefix, Set<String> allPackageNames) async {
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@jonasfj jonasfj Nov 7, 2024

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Change here simplified a bit, just list all files, extract package name from the object name and if the package doesn't exist, we delete it if it's older than _minGarbageAge

_log.info('Garbage collecting "$prefix"');

await _listBucket(prefix: prefix + '/api/packages/', delimiter: '/',
(item) async {
final String packageName;
if (item.isObject) {
assert(!item.name.endsWith('/'));
packageName = item.name.split('/').last;
} else {
assert(item.name.endsWith('/'));
packageName = item.name.without(suffix: '/').split('/').last;
}
if (!allPackageNames.contains(packageName)) {
final info = await _bucket.info(item.name);
if (info.updated.isBefore(clock.agoBy(_minGarbageAge))) {
// Only delete the item if it's older than _minGarbageAge
// This avoids any races where we delete files we've just created
await package(packageName).delete();
}
final gcFilesBefore = clock.agoBy(_minGarbageAge);

final pkgPrefix = '$prefix/api/packages/';
await _listBucket(prefix: pkgPrefix, delimiter: '', (entry) async {
final item = switch (entry) {
final BucketDirectoryEntry _ => throw AssertionError('unreachable'),
final BucketObjectEntry item => item,
};
final packageName = item.name.without(prefix: pkgPrefix).split('/').first;
if (!allPackageNames.contains(packageName) &&
item.updated.isBefore(gcFilesBefore)) {
// Only delete the item if it's older than _minGarbageAge
// This avoids any races where we delete files we've just created
// TODO: Conditionally deletion API from package:gcloud would be better!
await _bucket.tryDelete(item.name);
}
});

await _listBucket(prefix: prefix + '/api/archives/', delimiter: '-',
(item) async {
if (item.isObject) {
throw AssertionError('Unknown package archive at ${item.name}');
}
assert(item.name.endsWith('-'));
final packageName = item.name.without(suffix: '-').split('/').last;
if (!allPackageNames.contains(packageName)) {
final info = await _bucket.info(item.name);
if (info.updated.isBefore(clock.agoBy(_minGarbageAge))) {
// Only delete the item if it's older than _minGarbageAge
// This avoids any races where we delete files we've just created
await package(packageName).delete();
}
final archivePrefix = '$prefix/api/archives/';
await _listBucket(prefix: archivePrefix, delimiter: '', (entry) async {
final item = switch (entry) {
final BucketDirectoryEntry _ => throw AssertionError('unreachable'),
final BucketObjectEntry item => item,
};
final packageName =
item.name.without(prefix: archivePrefix).split('-').first;
if (!allPackageNames.contains(packageName) &&
item.updated.isBefore(gcFilesBefore)) {
// Only delete the item if it's older than _minGarbageAge
// This avoids any races where we delete files we've just created
await _bucket.tryDelete(item.name);
}
});
}
Expand Down Expand Up @@ -452,14 +449,14 @@ const _validatedCustomHeader = 'validated';
///
/// This allows us to detect files that are present, but not being updated
/// anymore. We classify such files as _stray files_ and write alerts to logs.
const _updateValidatedAfter = Duration(days: 1);
const _updateValidatedAfter = Duration(days: 3);
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@jonasfj jonasfj Nov 7, 2024

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Idea being that we don't want to update meta-data all the time.


/// Duration after which a file that haven't been updated is considered stray!
///
/// We don't delete stray files, because there shouldn't be any, so a stray file
/// is always indicative of a bug. Nevertheless, we write alerts to logs, so
/// that these inconsistencies can be detected.
const _unvalidatedStrayFileAfter = Duration(days: 7);
const _unvalidatedStrayFileAfter = Duration(days: 12);
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@jonasfj jonasfj Nov 7, 2024

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Let's wait a LONG time before we consider something a stray file

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@isoos isoos Nov 7, 2024

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I'm wondering: will we look at the logs or have alerts that fire within this period?

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@jonasfj jonasfj Nov 7, 2024

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No, after 12 days we'll consider a file stray, and then we'll see it in logs.


/// Interface for an exported JSON file.
///
Expand Down
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