Summary:
The Env registration framework supports registering client Envs and selecting which one to instantiate according to a text field. This enabled things like adding the -env_uri argument to db_bench, so the same binary could be reused with different Envs just by changing CLI config.
Now this problem has come up again in a non-Env context, as I want to instantiate a client Statistics implementation from db_bench, which is configured entirely via text parameters. Also, in the future we may wish to use it for deserializing client objects when loading OPTIONS file.
This diff generalizes the Env registration logic to work with arbitrary types.
- Generalized registration and instantiation code by templating them
- The entire implementation is in a header file as that's Google style guide's recommendation for template definitions
- Pattern match with std::regex_match rather than checking prefix, which was the previous behavior
- Rename functions/files to be non-Env-specific
Closes https://github.com/facebook/rocksdb/pull/1776
Differential Revision: D4421933
Pulled By: ajkr
fbshipit-source-id: 34647d1
Summary:
This enables configurable Envs without recompiling. For example, my
next diff will make env_test test an Env created by NewEnvFromUri(). Then,
users can determine which Env is tested simply by providing the URI for
NewEnvFromUri() (e.g., through a CLI argument or environment variable).
The registration process allows us to register any Env that is linked with the
RocksDB library, so we can register our internal Envs as well.
The registration code is inspired by our internal InitRegistry.
Test Plan: new unit test
Reviewers: IslamAbdelRahman, lightmark, ldemailly, sdong
Reviewed By: sdong
Subscribers: leveldb, dhruba, andrewkr
Differential Revision: https://reviews.facebook.net/D58449
Andrew Kryczka