view tests/test-stream-bundle-v2.t @ 39561:d06834e0f48e

wireprotov2peer: stream decoded responses

Previously, wire protocol version 2 would buffer all response data.
Only once all data was received did we CBOR decode it and resolve
the future associated with the command. This was obviously not
desirable. In future commits that introduce large response payloads,
this caused significant memory bloat and slowed down client
operations due to waiting on the server.

This commit refactors the response handling code so that response
data can be streamed.

Command response objects now contain a buffered CBOR decoder. As
new data arrives, it is fed into the decoder. Decoded objects are
made available to the generator as they are decoded.

Because there is a separate thread processing incoming frames and
feeding data into the response object, there is the potential for
race conditions when mutating response objects. So a lock has been
added to guard access to critical state variables.

Because the generator emitting decoded objects needs to wait on
those objects to become available, we've added an Event for the
generator to wait on so it doesn't busy loop. This does mean
there is the potential for deadlocks. And I'm pretty sure they can
occur in some scenarios. We already have a handful of TODOs around
this. But I've added some more. Fixing this will likely require
moving the background thread receiving frames into clienthandler.
We likely would have done this anyway when implementing the client
bits for the SSH transport.

Test output changes because the initial CBOR map holding the overall
response state is now always handled internally by the response
object.

Differential Revision: https://phab.mercurial-scm.org/D4474

#require no-reposimplestore

Test creating a consuming stream bundle v2

  $ getmainid() {
  >    hg -R main log --template '{node}\n' --rev "$1"
  > }

  $ cp $HGRCPATH $TESTTMP/hgrc.orig

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution.createmarkers=True
  > evolution.exchange=True
  > bundle2-output-capture=True
  > [ui]
  > ssh="$PYTHON" "$TESTDIR/dummyssh"
  > logtemplate={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
  > [web]
  > push_ssl = false
  > allow_push = *
  > [phases]
  > publish=False
  > [extensions]
  > drawdag=$TESTDIR/drawdag.py
  > clonebundles=
  > EOF

The extension requires a repo (currently unused)

  $ hg init main
  $ cd main

  $ hg debugdrawdag <<'EOF'
  > E
  > |
  > D
  > |
  > C
  > |
  > B
  > |
  > A
  > EOF

  $ hg bundle -a --type="none-v2;stream=v2" bundle.hg
  $ hg debugbundle bundle.hg
  Stream params: {}
  stream2 -- {bytecount: 1693, filecount: 11, requirements: dotencode%2Cfncache%2Cgeneraldelta%2Crevlogv1%2Cstore} (mandatory: True)
  $ hg debugbundle --spec bundle.hg
  none-v2;stream=v2;requirements%3Ddotencode%2Cfncache%2Cgeneraldelta%2Crevlogv1%2Cstore

Test that we can apply the bundle as a stream clone bundle

  $ cat > .hg/clonebundles.manifest << EOF
  > http://localhost:$HGPORT1/bundle.hg BUNDLESPEC=`hg debugbundle --spec bundle.hg`
  > EOF

  $ hg serve -d -p $HGPORT --pid-file hg.pid --accesslog access.log
  $ cat hg.pid >> $DAEMON_PIDS

  $ "$PYTHON" $TESTDIR/dumbhttp.py -p $HGPORT1 --pid http.pid
  $ cat http.pid >> $DAEMON_PIDS

  $ cd ..
  $ hg clone http://localhost:$HGPORT streamv2-clone-implicit --debug
  using http://localhost:$HGPORT/
  sending capabilities command
  sending clonebundles command
  applying clone bundle from http://localhost:$HGPORT1/bundle.hg
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "stream2" (params: 3 mandatory) supported
  applying stream bundle
  11 files to transfer, 1.65 KB of data
  starting 4 threads for background file closing (?)
  starting 4 threads for background file closing (?)
  adding [s] data/A.i (66 bytes)
  adding [s] data/B.i (66 bytes)
  adding [s] data/C.i (66 bytes)
  adding [s] data/D.i (66 bytes)
  adding [s] data/E.i (66 bytes)
  adding [s] 00manifest.i (584 bytes)
  adding [s] 00changelog.i (595 bytes)
  adding [s] phaseroots (43 bytes)
  adding [c] branch2-served (94 bytes)
  adding [c] rbc-names-v1 (7 bytes)
  adding [c] rbc-revs-v1 (40 bytes)
  transferred 1.65 KB in \d\.\d seconds \(.*/sec\) (re)
  bundle2-input-part: total payload size 1840
  bundle2-input-bundle: 0 parts total
  updating the branch cache
  finished applying clone bundle
  query 1; heads
  sending batch command
  searching for changes
  all remote heads known locally
  no changes found
  sending getbundle command
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-part: "phase-heads" supported
  bundle2-input-part: total payload size 24
  bundle2-input-bundle: 1 parts total
  checking for updated bookmarks
  updating to branch default
  resolving manifests
   branchmerge: False, force: False, partial: False
   ancestor: 000000000000, local: 000000000000+, remote: 9bc730a19041
   A: remote created -> g
  getting A
   B: remote created -> g
  getting B
   C: remote created -> g
  getting C
   D: remote created -> g
  getting D
   E: remote created -> g
  getting E
  5 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone --stream http://localhost:$HGPORT streamv2-clone-explicit --debug
  using http://localhost:$HGPORT/
  sending capabilities command
  sending clonebundles command
  applying clone bundle from http://localhost:$HGPORT1/bundle.hg
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "stream2" (params: 3 mandatory) supported
  applying stream bundle
  11 files to transfer, 1.65 KB of data
  starting 4 threads for background file closing (?)
  starting 4 threads for background file closing (?)
  adding [s] data/A.i (66 bytes)
  adding [s] data/B.i (66 bytes)
  adding [s] data/C.i (66 bytes)
  adding [s] data/D.i (66 bytes)
  adding [s] data/E.i (66 bytes)
  adding [s] 00manifest.i (584 bytes)
  adding [s] 00changelog.i (595 bytes)
  adding [s] phaseroots (43 bytes)
  adding [c] branch2-served (94 bytes)
  adding [c] rbc-names-v1 (7 bytes)
  adding [c] rbc-revs-v1 (40 bytes)
  transferred 1.65 KB in *.* seconds (*/sec) (glob)
  bundle2-input-part: total payload size 1840
  bundle2-input-bundle: 0 parts total
  updating the branch cache
  finished applying clone bundle
  query 1; heads
  sending batch command
  searching for changes
  all remote heads known locally
  no changes found
  sending getbundle command
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-part: "phase-heads" supported
  bundle2-input-part: total payload size 24
  bundle2-input-bundle: 1 parts total
  checking for updated bookmarks
  updating to branch default
  resolving manifests
   branchmerge: False, force: False, partial: False
   ancestor: 000000000000, local: 000000000000+, remote: 9bc730a19041
   A: remote created -> g
  getting A
   B: remote created -> g
  getting B
   C: remote created -> g
  getting C
   D: remote created -> g
  getting D
   E: remote created -> g
  getting E
  5 files updated, 0 files merged, 0 files removed, 0 files unresolved