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view tests/test-narrow-pull.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
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 13 Apr 2018 11:02:34 -0700 |
parents | 802742769680 |
children | 576eef1ab43d |
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$ . "$TESTDIR/narrow-library.sh" $ hg init master $ cd master $ cat >> .hg/hgrc <<EOF > [narrow] > serveellipses=True > EOF $ for x in `$TESTDIR/seq.py 10` > do > echo $x > "f$x" > hg add "f$x" > hg commit -m "Commit f$x" > done $ cd .. narrow clone a couple files, f2 and f8 $ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8" requesting all changes adding changesets adding manifests adding file changes added 5 changesets with 2 changes to 2 files new changesets *:* (glob) updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd narrow $ ls f2 f8 $ cat f2 f8 2 8 $ cd .. change every upstream file twice $ cd master $ for x in `$TESTDIR/seq.py 10` > do > echo "update#1 $x" >> "f$x" > hg commit -m "Update#1 to f$x" "f$x" > done $ for x in `$TESTDIR/seq.py 10` > do > echo "update#2 $x" >> "f$x" > hg commit -m "Update#2 to f$x" "f$x" > done $ cd .. look for incoming changes $ cd narrow $ hg incoming --limit 3 comparing with ssh://user@dummy/master searching for changes changeset: 5:ddc055582556 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f1 changeset: 6:f66eb5ad621d user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f2 changeset: 7:c42ecff04e99 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Update#1 to f3 Interrupting the pull is safe $ hg --config hooks.pretxnchangegroup.bad=false pull -q transaction abort! rollback completed abort: pretxnchangegroup.bad hook exited with status 1 [255] $ hg id 223311e70a6f tip pull new changes down to the narrow clone. Should get 8 new changesets: 4 relevant to the narrow spec, and 4 ellipsis nodes gluing them all together. $ hg pull pulling from ssh://user@dummy/master searching for changes adding changesets adding manifests adding file changes added 9 changesets with 4 changes to 2 files new changesets *:* (glob) (run 'hg update' to get a working copy) $ hg log -T '{rev}: {desc}\n' 13: Update#2 to f10 12: Update#2 to f8 11: Update#2 to f7 10: Update#2 to f2 9: Update#2 to f1 8: Update#1 to f8 7: Update#1 to f7 6: Update#1 to f2 5: Update#1 to f1 4: Commit f10 3: Commit f8 2: Commit f7 1: Commit f2 0: Commit f1 $ hg update tip 2 files updated, 0 files merged, 0 files removed, 0 files unresolved add a change and push it $ echo "update#3 2" >> f2 $ hg commit -m "Update#3 to f2" f2 $ hg log f2 -T '{rev}: {desc}\n' 14: Update#3 to f2 10: Update#2 to f2 6: Update#1 to f2 1: Commit f2 $ hg push pushing to ssh://user@dummy/master searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 1 changesets with 1 changes to 1 files $ cd .. $ cd master $ hg log f2 -T '{rev}: {desc}\n' 30: Update#3 to f2 21: Update#2 to f2 11: Update#1 to f2 1: Commit f2 $ hg log -l 3 -T '{rev}: {desc}\n' 30: Update#3 to f2 29: Update#2 to f10 28: Update#2 to f9 Can pull into repo with a single commit $ cd .. $ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0 $ cd narrow2 $ hg pull -q -r 1 transaction abort! rollback completed abort: pull failed on remote [255] Can use 'hg share': $ cat >> $HGRCPATH <<EOF > [extensions] > share= > EOF $ cd .. $ hg share narrow2 narrow2-share updating working directory 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd narrow2-share $ hg status We should also be able to unshare without breaking everything: $ hg unshare devel-warn: write with no wlock: "narrowspec" at: */hgext/narrow/narrowrepo.py:* (unsharenarrowspec) (glob) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions