i3wangyi commented on a change in pull request #367: Add transient cache for
CustomRestClient implementation
URL: https://github.com/apache/helix/pull/367#discussion_r310786737
##########
File path:
helix-rest/src/main/java/org/apache/helix/rest/client/CustomRestClientImpl.java
##########
@@ -97,7 +106,43 @@ public CustomRestClientImpl(HttpClient httpClient) {
kv -> result.put(kv.getKey(),
kv.getValue().get(IS_HEALTHY_FIELD).asBoolean()));
return result;
};
- return handleResponse(post(url, payLoads), jsonConverter);
+ String requestId = baseUrl + customPayloads.toString() +
partitions.toString();
+ try {
+ lock(requestId);
+ if (_cachedResults.containsKey(requestId)) {
+ return _cachedResults.get(requestId);
+ }
+ Map<String, Boolean> result = handleResponse(post(url, payLoads),
jsonConverter);
+ _cachedResults.put(requestId, result);
+ return result;
+ } catch (InterruptedException e) {
+ e.printStackTrace();
+ } finally {
+ unlock(requestId);
+ }
+ return Collections.emptyMap();
+ }
+
+ @VisibleForTesting
+ Map<String, Map<String, Boolean>> getCachedResults() {
+ return _cachedResults;
+ }
+
+ private void lock(String key) throws InterruptedException {
+ synchronized (lockedKeys) {
Review comment:
It is locked on key level, my unit test just verifies it. See the below
debug message, other thread is able to acquire a different key before others
release the key
```
Thread: 7 acquired key http://localhost:1000{}[Thread: 7]
Thread: 4 acquired key http://localhost:1000{}[Thread: 4]
Thread: 6 acquired key http://localhost:1000{}[Thread: 6]
Thread: 0 acquired key http://localhost:1000{}[Thread: 0]
Thread: 9 acquired key http://localhost:1000{}[Thread: 9]
Thread: 5 acquired key http://localhost:1000{}[Thread: 5]
Thread: 2 acquired key http://localhost:1000{}[Thread: 2]
Thread: 8 acquired key http://localhost:1000{}[Thread: 8]
Thread: 3 acquired key http://localhost:1000{}[Thread: 3]
Thread: 1 acquired key http://localhost:1000{}[Thread: 1]
Thread: 4 release lock for http://localhost:1000{}[Thread: 4]
Thread: 9 release lock for http://localhost:1000{}[Thread: 9]
Thread: 2 release lock for http://localhost:1000{}[Thread: 2]
Thread: 1 release lock for http://localhost:1000{}[Thread: 1]
Thread: 6 release lock for http://localhost:1000{}[Thread: 6]
Thread: 0 release lock for http://localhost:1000{}[Thread: 0]
Thread: 3 release lock for http://localhost:1000{}[Thread: 3]
Thread: 8 release lock for http://localhost:1000{}[Thread: 8]
Thread: 7 release lock for http://localhost:1000{}[Thread: 7]
Thread: 5 release lock for http://localhost:1000{}[Thread: 5]
```
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