Vincent Devillers created KNOX-807:
--------------------------------------
Summary: Missing resource deallocation
Key: KNOX-807
URL: https://issues.apache.org/jira/browse/KNOX-807
Project: Apache Knox
Issue Type: Bug
Reporter: Vincent Devillers
h2. Release connection to pool after HTTP call
The close() method in BasicResponse does only
EntityUtils.consumeQuietly(response.getEntity()):
{code}
public void close() {
this.consume();
}
public void consume() {
if(!this.consumed) {
EntityUtils.consumeQuietly(this.response.getEntity());
this.consumed = true;
}
}
{code}
The underlying HTTP connection is still held. In order to ensure correct
deallocation of OS resources we need to call CloseableHttpResponse#close() like
this:
{code}
public void close() {
try {
this.consume();
} finally {
if (response instanceof CloseableHttpResponse) {
try {
((CloseableHttpResponse) response).close();
} catch (IOException e) {
throw Throwables.propagate(e);
}
}
}
}
{code}
h2. Shutdown connection pool
Also when the Hadoop session is no more used, the only method present by to be
call is shutdown(), but it close only the ExecutorService. When a
CloseableHttpClient instance is no longer needed, we have to shut down the
connection manager to ensure immediate deallocation of all OS resources.
{code}
public void close() {
try {
executor.shutdownNow();
} catch(Exception e) {
// log something here
}
try {
client.close();
// client.close() should call getConnectionManager().shutdown();
} catch(Exception e) {
// log something here
}
}
{code}
[Source|https://blog.layer4.fr/2016/12/06/knox-production-pitfalls-and-common-mistakes/]
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