Hi. Using Akka HTTP & Streams 1.0-RC3 in Scala, I have the impression that a connection can be used to pipeline another request even if a non-idempotent request is being executed (vs. a non-idempotent request being completed). I had the same problem in 1.0-RC2 but took no time to investigate.
The context: I’m using an in-house library to access CouchDB databases over HTTP named “canape”. I create a database and wait for the result, I then open a long-running connection to the “_changes” stream which returns live database changes and send them to a “fold” sink in the background, and I immediately create 5 documents named “docid“ and wait for 100 milliseconds after every document creation. In the example below, we have a single TCP stream dumped with wireshark. Note how the request to “_changes” (which represents a live stream of changes in CouchDB) returns a chunked response, and the chunked response is obviously not over when the PUT to create the second document (“docid2”) is sent over the same connection. Even though I took care of using POST to ensure that Akka does see the “_changes” request as non-idempotent. Note that the first document (“docid1”) has been created on another TCP connection (and thus not shown here), probably because it has been sent right after the request to the “_changes” stream, which means that at this time Akka probably considered the non-idempotent request to be running. However, the second document is being created on the busy original TCP connection, as if as soon as the headers were sent back the connection is considered idle again, although its entity is still being transmitted and may be for a long time. Since the PUT for “docid2” is still blocked on this connection, we can also see that “docid3”, “docid4” and “docid5” have been properly created using another TCP connection. Right now, I work around this by creating a new host connection pool for every long-running connection, but it is a waste or resources and causes some code duplication. The problem shown below happens when I try to use a common pool for all requests (which should work fine). Any idea of what might be wrong here? > PUT /canape-test-db-d45ad182-e2ec-4387-b5a1-a51d016c0312/ HTTP/1.1 > Host: localhost:5984 > User-Agent: canape for Scala > Accept: application/json > Content-Length: 0 > < HTTP/1.1 201 Created < Server: CouchDB/1.6.1 (Erlang OTP/17) < Location: http://localhost:5984/canape-test-db-d45ad182-e2ec-4387-b5a1-a51d016c0312 < Date: Wed, 27 May 2015 16:43:24 GMT < Content-Type: application/json < Content-Length: 12 < Cache-Control: must-revalidate < < {"ok":true} > POST > /canape-test-db-d45ad182-e2ec-4387-b5a1-a51d016c0312/_changes?feed=continuous > HTTP/1.1 > Host: localhost:5984 > User-Agent: canape for Scala > Accept: application/json > Content-Type: application/json > Content-Length: 2 > > {} < HTTP/1.1 200 OK < Transfer-Encoding: chunked < Server: CouchDB/1.6.1 (Erlang OTP/17) < Date: Wed, 27 May 2015 16:43:25 GMT < Content-Type: application/json < Cache-Control: must-revalidate < < 51 < {"seq":1,"id":"docid1","changes":[{"rev":"1-967a00dff5e02add41819138abb3284d"}]} < > PUT /canape-test-db-d45ad182-e2ec-4387-b5a1-a51d016c0312/docid2 HTTP/1.1 > Host: localhost:5984 > User-Agent: canape for Scala > Accept: application/json > Content-Type: application/json > Content-Length: 2 > > {} < 51 < {"seq":2,"id":"docid3","changes":[{"rev":"1-967a00dff5e02add41819138abb3284d"}]} < < 51 < {"seq":3,"id":"docid4","changes":[{"rev":"1-967a00dff5e02add41819138abb3284d"}]} < < 51 < {"seq":4,"id":"docid5","changes":[{"rev":"1-967a00dff5e02add41819138abb3284d"}]} (hangs there, as the connection is still busy sending the long-running _changes stream, the creation of “docid2” will timeout) -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
