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The following commit(s) were added to refs/heads/master by this push:
new b288435 Use a PoolingConnectionManager even for single connection
use-cases. (#3836)
b288435 is described below
commit b288435dfdb3c0f6bc5622d6cbb04aaa233f28b4
Author: Markus Thömmes <[email protected]>
AuthorDate: Tue Jul 3 18:00:20 2018 +0200
Use a PoolingConnectionManager even for single connection use-cases. (#3836)
The PoolingConnectionManager checks connections for their staleness, which
is important because we're pausing/resuming containers all the time.
Connections can go stale in this process.
---
.../scala/whisk/core/containerpool/HttpUtils.scala | 26 ++++++++++++++++------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git
a/common/scala/src/main/scala/whisk/core/containerpool/HttpUtils.scala
b/common/scala/src/main/scala/whisk/core/containerpool/HttpUtils.scala
index 4ff205d..c5faab4 100644
--- a/common/scala/src/main/scala/whisk/core/containerpool/HttpUtils.scala
+++ b/common/scala/src/main/scala/whisk/core/containerpool/HttpUtils.scala
@@ -38,7 +38,7 @@ import org.apache.http.client.utils.{HttpClientUtils,
URIBuilder}
import org.apache.http.conn.HttpHostConnectException
import org.apache.http.entity.StringEntity
import org.apache.http.impl.client.HttpClientBuilder
-import org.apache.http.impl.conn.{BasicHttpClientConnectionManager,
PoolingHttpClientConnectionManager}
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager
import spray.json._
import whisk.common.Logging
import whisk.common.TransactionId
@@ -62,6 +62,12 @@ import whisk.core.entity.size.SizeLong
protected class HttpUtils(hostname: String, timeout: FiniteDuration,
maxResponse: ByteSize, maxConcurrent: Int = 1)(
implicit logging: Logging) {
+ /**
+ * Closes the HttpClient and all resources allocated by it.
+ *
+ * This will close the HttpClient that is generated for this instance of
HttpUtils. That will also cause the
+ * ConnectionManager to be closed alongside.
+ */
def close() = Try(connection.close())
/**
@@ -159,15 +165,21 @@ protected class HttpUtils(hostname: String, timeout:
FiniteDuration, maxResponse
private val connection = HttpClientBuilder.create
.setDefaultRequestConfig(httpconfig)
- .setConnectionManager(if (maxConcurrent > 1) {
- // Use PoolingHttpClientConnectionManager so that concurrent activation
processing (if enabled) will reuse connections
- val cm = new PoolingHttpClientConnectionManager
- // Increase default max connections per route (default is 2)
+ .setConnectionManager({
+ // A PoolingHttpClientConnectionManager is the default when not
specifying any ConnectionManager.
+ // The PoolingHttpClientConnectionManager has the benefit of actively
checking if a connection has become stale,
+ // which is very important because pausing/resuming containers can cause
a connection to become silently broken.
+ // This causes very subtle bugs, especially when containers are reused
after a pretty long time (like > 5 minutes).
+ //
+ // The BasicHttpClientConnectionManager (which would be alternative
here) doesn't have such a mechanism and thus
+ // isn't suitable for our usage.
+ val cm = new PoolingHttpClientConnectionManager()
+ // perRoute effectively means per host in our use-case, which means
setting it to the same value as the maximum
+ // total of all connections in the pool is appropriate here.
cm.setDefaultMaxPerRoute(maxConcurrent)
- // Increase max total connections (default is 20)
cm.setMaxTotal(maxConcurrent)
cm
- } else new BasicHttpClientConnectionManager()) // set the Pooling
connection manager IFF maxConcurrent > 1
+ })
.useSystemProperties()
.disableAutomaticRetries()
.build
