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author | Lin Jen-Shin <godfat@godfat.org> | 2018-06-21 14:46:52 +0300 |
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committer | Lin Jen-Shin <godfat@godfat.org> | 2018-06-22 13:18:42 +0300 |
commit | d5c7fe29c863564d631f48a2b6e81241b5171aaf (patch) | |
tree | e0c6f8b9e83ae8f0efe80c65cd5399bdd174b2e4 /doc/development | |
parent | 14e35ac9b19d358d84e0cfd167f74036937285b6 (diff) |
Add docs for RequestCache, moved from comments
Diffstat (limited to 'doc/development')
-rw-r--r-- | doc/development/utilities.md | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/doc/development/utilities.md b/doc/development/utilities.md index 8f9aff1a35f..0d074a3ef05 100644 --- a/doc/development/utilities.md +++ b/doc/development/utilities.md @@ -135,3 +135,44 @@ We developed a number of utilities to ease development. Find.new.clear_memoization(:result) ``` + +## [`RequestCache`](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/gitlab/cache/request_cache.rb) + +This module provides a simple way to cache values in RequestStore, +and the cache key would be based on the class name, method name, +optionally customized instance level values, optionally customized +method level values, and optional method arguments. + +A simple example that only uses the instance level customised values: + +``` ruby +class UserAccess + extend Gitlab::Cache::RequestCache + + request_cache_key do + [user&.id, project&.id] + end + + request_cache def can_push_to_branch?(ref) + # ... + end +end +``` + +This way, the result of `can_push_to_branch?` would be cached in +`RequestStore.store` based on the cache key. If `RequestStore` is not +currently active, then it would be stored in a hash saved in an +instance variable, so the cache logic would be the same. + +We can also set different strategies for different methods: + +``` ruby +class Commit + extend Gitlab::Cache::RequestCache + + def author + User.find_by_any_email(author_email.downcase) + end + request_cache(:author) { author_email.downcase } +end +``` |