Mercurial > hg
view tests/test-debugbuilddag.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 | 95f490136e75 |
children | 8d6109b49b31 |
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plain $ hg init $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' \ > --config extensions.progress= --config progress.assume-tty=1 \ > --config progress.delay=0 --config progress.refresh=0 \ > --config progress.format=topic,bar,number \ > --config progress.width=60 \r (no-eol) (esc) building [ ] 0/12\r (no-eol) (esc) building [ ] 0/12\r (no-eol) (esc) building [==> ] 1/12\r (no-eol) (esc) building [==> ] 1/12\r (no-eol) (esc) building [======> ] 2/12\r (no-eol) (esc) building [=========> ] 3/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [=============> ] 4/12\r (no-eol) (esc) building [================> ] 5/12\r (no-eol) (esc) building [====================> ] 6/12\r (no-eol) (esc) building [=======================> ] 7/12\r (no-eol) (esc) building [===========================> ] 8/12\r (no-eol) (esc) building [===========================> ] 8/12\r (no-eol) (esc) building [==============================> ] 9/12\r (no-eol) (esc) building [==================================> ] 10/12\r (no-eol) (esc) building [=====================================> ] 11/12\r (no-eol) (esc) \r (no-eol) (esc) tags $ cat .hg/localtags 66f7d451a68b85ed82ff5fcc254daf50c74144bd f bebd167eb94d257ace0e814aeb98e6972ed2970d p2 dag $ hg debugdag -t -b +2:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [] @ 0.00 overwritten files, starting on a non-default branch $ rm -r .hg $ hg init $ hg debugbuilddag '@start.@default.:f +3:p2 @temp <f+4 @default /p2 +2' -q -o tags $ cat .hg/localtags f778700ebd50fcf282b23a4446bd155da6453eb6 f bbccf169769006e2490efd2a02f11c3d38d462bd p2 dag $ hg debugdag -t -b @start+1 @default+1:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [start] @ 0.00 glog of $ hg log -G --template '{rev}: {desc} [{branches}]\n' of o 11: r11 [] | o 10: r10 [] | o 9: r9 [] |\ | o 8: r8 [temp] | | | o 7: r7 [temp] | | | o 6: r6 [temp] | | | o 5: r5 [temp] | | o | 4: r4 [] | | o | 3: r3 [] | | o | 2: r2 [] |/ o 1: r1 [] | o 0: r0 [start] tags $ hg tags -v tip 11:9ffe238a67a2 p2 4:bbccf1697690 local f 1:f778700ebd50 local cat of $ hg cat of --rev tip r11 new and mergeable files $ rm -r .hg $ hg init $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' -q -mn dag $ hg debugdag -t -b +2:f +3:p2 @temp*f+3 @default*/p2+2:tip tip $ hg id 000000000000 glog $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n' o 11: r11 [] @ 11.00 | o 10: r10 [] @ 10.00 | o 9: r9 [] @ 9.00 |\ | o 8: r8 [temp] @ 8.00 | | | o 7: r7 [temp] @ 7.00 | | | o 6: r6 [temp] @ 6.00 | | | o 5: r5 [temp] @ 5.00 | | o | 4: r4 [] @ 4.00 | | o | 3: r3 [] @ 3.00 | | o | 2: r2 [] @ 2.00 |/ o 1: r1 [] @ 1.00 | o 0: r0 [] @ 0.00 glog mf $ hg log -G --template '{rev}: {desc} [{branches}]\n' mf o 11: r11 [] | o 10: r10 [] | o 9: r9 [] |\ | o 8: r8 [temp] | | | o 7: r7 [temp] | | | o 6: r6 [temp] | | | o 5: r5 [temp] | | o | 4: r4 [] | | o | 3: r3 [] | | o | 2: r2 [] |/ o 1: r1 [] | o 0: r0 [] man r4 $ hg manifest -r4 mf nf0 nf1 nf2 nf3 nf4 cat r4 mf $ hg cat -r4 mf 0 r0 1 2 r1 3 4 r2 5 6 r3 7 8 r4 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 man r8 $ hg manifest -r8 mf nf0 nf1 nf5 nf6 nf7 nf8 cat r8 mf $ hg cat -r8 mf 0 r0 1 2 r1 3 4 5 6 7 8 9 10 r5 11 12 r6 13 14 r7 15 16 r8 17 18 19 20 21 22 23 man $ hg manifest --rev tip mf nf0 nf1 nf10 nf11 nf2 nf3 nf4 nf5 nf6 nf7 nf8 nf9 cat mf $ hg cat mf --rev tip 0 r0 1 2 r1 3 4 r2 5 6 r3 7 8 r4 9 10 r5 11 12 r6 13 14 r7 15 16 r8 17 18 r9 19 20 r10 21 22 r11 23