view tests/test-push-cgi.t @ 37631:2f626233859b

wireproto: implement batching on peer executor interface

This is a bit more complicated than non-batch requests because we
need to buffer sends until the last request arrives *and* we need
to support resolving futures as data arrives from the remote.

In a classical concurrent.futures executor model, the future
"starts" as soon as it is submitted. However, we have nothing to
start until the last command is submitted.

If we did nothing, calling result() would deadlock, since the future
hasn't "started." So in the case where we queue the command, we return
a special future type whose result() will trigger sendcommands().
This eliminates the deadlock potential. It also serves as a check
against callers who may be calling result() prematurely, as it will
prevent any subsequent callcommands() from working. This behavior
is slightly annoying and a bit restrictive. But it's the world
that half duplex connections forces on us.

In order to support streaming responses, we were previously using
a generator. But with a futures-based API, we're using futures
and not generators. So in order to get streaming, we need a
background thread to read data from the server.

The approach taken in this patch is to leverage the ThreadPoolExecutor
from concurrent.futures for managing a background thread. We create
an executor and future that resolves when all response data is
processed (or an error occurs). When exiting the context manager,
we wait on that background reading before returning.

I was hoping we could manually spin up a threading.Thread and this
would be simple. But I ran into a few deadlocks when implementing.
After looking at the source code to concurrent.futures, I figured
it would just be easier to use a ThreadPoolExecutor than implement
all the code needed to manually manage a thread.

To prove this works, a use of the batch API in discovery has been
updated.

Differential Revision: https://phab.mercurial-scm.org/D3269

#require no-msys # MSYS will translate web paths as if they were file paths

This is a test of the push wire protocol over CGI-based hgweb.

initialize repository

  $ hg init r
  $ cd r
  $ echo a > a
  $ hg ci -A -m "0"
  adding a
  $ echo '[web]' > .hg/hgrc
  $ echo 'allow_push = *' >> .hg/hgrc
  $ echo 'push_ssl = false' >> .hg/hgrc

create hgweb invocation script

  $ cat >hgweb.cgi <<HGWEB
  > import cgitb
  > cgitb.enable()
  > from mercurial import demandimport; demandimport.enable()
  > from mercurial.hgweb import hgweb
  > from mercurial.hgweb import wsgicgi
  > application = hgweb('.', 'test repository')
  > wsgicgi.launch(application)
  > HGWEB
  $ chmod 755 hgweb.cgi

test preparation

  $ . "$TESTDIR/cgienv"
  $ REQUEST_METHOD="POST"; export REQUEST_METHOD
  $ CONTENT_TYPE="application/octet-stream"; export CONTENT_TYPE
  $ hg bundle --type v1 --all bundle.hg
  1 changesets found
  $ CONTENT_LENGTH=279; export CONTENT_LENGTH;

expect failure because heads doesn't match (formerly known as 'unsynced changes')

  $ QUERY_STRING="cmd=unbundle&heads=0000000000000000000000000000000000000000"; export QUERY_STRING
  $ $PYTHON hgweb.cgi <bundle.hg >page1 2>&1
  $ cat page1
  Status: 200 Script output follows\r (esc)
  Content-Type: application/mercurial-0.1\r (esc)
  Content-Length: 64\r (esc)
  \r (esc)
  0
  repository changed while preparing changes - please try again

successful force push

  $ QUERY_STRING="cmd=unbundle&heads=666f726365"; export QUERY_STRING
  $ $PYTHON hgweb.cgi <bundle.hg >page2 2>&1
  $ cat page2
  Status: 200 Script output follows\r (esc)
  Content-Type: application/mercurial-0.1\r (esc)
  Content-Length: 102\r (esc)
  \r (esc)
  1
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files

successful push, list of heads

  $ QUERY_STRING="cmd=unbundle&heads=f7b1eb17ad24730a1651fccd46c43826d1bbc2ac"; export QUERY_STRING
  $ $PYTHON hgweb.cgi <bundle.hg >page3 2>&1
  $ cat page3
  Status: 200 Script output follows\r (esc)
  Content-Type: application/mercurial-0.1\r (esc)
  Content-Length: 102\r (esc)
  \r (esc)
  1
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files

successful push, SHA1 hash of heads (unbundlehash capability)

  $ QUERY_STRING="cmd=unbundle&heads=686173686564 5a785a5f9e0d433b88ed862b206b011b0c3a9d13"; export QUERY_STRING
  $ $PYTHON hgweb.cgi <bundle.hg >page4 2>&1
  $ cat page4
  Status: 200 Script output follows\r (esc)
  Content-Type: application/mercurial-0.1\r (esc)
  Content-Length: 102\r (esc)
  \r (esc)
  1
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files

  $ cd ..