Mercurial > hg
annotate hgweb.cgi @ 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> |
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date | Fri, 13 Apr 2018 11:02:34 -0700 |
parents | 4b0fc75f9403 |
children | 47ef023d0165 |
rev | line source |
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202 | 1 #!/usr/bin/env python |
159 | 2 # |
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hgweb: simplify hgweb.cgi, add help pointer
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3 # An example hgweb CGI script, edit as necessary |
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urls: bulk-change primary website URLs
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4 # See also https://mercurial-scm.org/wiki/PublishingRepositories |
159 | 5 |
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6 # Path to repo or hgweb config to serve (see 'hg help hgweb') |
338167735124
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Matt Mackall <mpm@selenic.com>
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7 config = "/path/to/repo/or/config" |
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cgi: sys.path.insert should be before importing mercurial
Benoit Boissinot <benoit.boissinot@ens-lyon.org>
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8 |
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hgweb: add hint about finding library path with debuginstall
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9 # Uncomment and adjust if Mercurial is not installed system-wide |
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10 # (consult "installed modules" path from 'hg debuginstall'): |
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Matt Mackall <mpm@selenic.com>
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11 #import sys; sys.path.insert(0, "/path/to/python/lib") |
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Enable demandimport only in scripts, not in importable modules (issue605)
Thomas Arendsen Hein <thomas@intevation.de>
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12 |
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hgweb: disable cgitb by default
Maxim Dounin <mdounin@mdounin.ru>
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13 # Uncomment to send python tracebacks to the browser if an error occurs: |
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14 #import cgitb; cgitb.enable() |
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hgweb: pull cgitb into CGI script example, where it can easily be disabled
mpm@selenic.com
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15 |
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hgweb: simplify hgweb.cgi, add help pointer
Matt Mackall <mpm@selenic.com>
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16 from mercurial import demandimport; demandimport.enable() |
338167735124
hgweb: simplify hgweb.cgi, add help pointer
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parents:
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17 from mercurial.hgweb import hgweb, wsgicgi |
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18 application = hgweb(config) |
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Backed out changeset b913d3aacddc (see issue971/msg5317)
Thomas Arendsen Hein <thomas@intevation.de>
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19 wsgicgi.launch(application) |