fix: resolve EnvironmentProvider race under concurrent resolveEnvironment()#169
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dminkley wants to merge 1 commit into
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fix: resolve EnvironmentProvider race under concurrent resolveEnvironment()#169dminkley wants to merge 1 commit into
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resolveEnvironment() let multiple threads past the null check before the CompletableFuture resolved, so probe() could run on several Environments concurrently and a non-deterministic one could win the cache. Under ECS + FireLens this intermittently cached an ECSEnvironment whose getLogGroupName() is "", dropping the LogGroup dimension for the JVM's lifetime. Make cachedEnvironment volatile and resolve it once via double-checked locking. Add a deterministic regression test that forces concurrent callers and asserts probe() runs exactly once. Fixes awslabs#168
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resolveEnvironment() let multiple threads past the null check before the
CompletableFuture resolved, so probe() could run on several Environments
concurrently and a non-deterministic one could win the cache. Under ECS +
FireLens this intermittently cached an ECSEnvironment whose getLogGroupName()
is "", dropping the LogGroup dimension for the JVM's lifetime.
Make cachedEnvironment volatile and resolve it once via double-checked
locking. Add a deterministic regression test that forces concurrent callers
and asserts probe() runs exactly once.
Fixes #168
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