view tests/test-bundle.t @ 26623:5a95fe44121d

clonebundles: support for seeding clones from pre-generated bundles

Cloning can be an expensive operation for servers because the server
generates a bundle from existing repository data at request time. For
a large repository like mozilla-central, this consumes 4+ minutes
of CPU time on the server. It also results in significant network
utilization. Multiplied by hundreds or even thousands of clients and
the ensuing load can result in difficulties scaling the Mercurial server.

Despite generation of bundles being deterministic until the next
changeset is added, the generation of bundles to service a clone request
is not cached. Each clone thus performs redundant work. This is
wasteful.

This patch introduces the "clonebundles" extension and related
client-side functionality to help alleviate this deficiency. The
client-side feature is behind an experimental flag and is not enabled by
default.

It works as follows:

1) Server operator generates a bundle and makes it available on a
   server (likely HTTP).
2) Server operator defines the URL of a bundle file in a
   .hg/clonebundles.manifest file.
3) Client `hg clone`ing sees the server is advertising bundle URLs.
4) Client fetches and applies the advertised bundle.
5) Client performs equivalent of `hg pull` to fetch changes made since
   the bundle was created.

Essentially, the server performs the expensive work of generating a
bundle once and all subsequent clones fetch a static file from
somewhere. Scaling static file serving is a much more manageable
problem than scaling a Python application like Mercurial. Assuming your
repository grows less than 1% per day, the end result is 99+% of CPU
and network load from clones is eliminated, allowing Mercurial servers
to scale more easily. Serving static files also means data can be
transferred to clients as fast as they can consume it, rather than as
fast as servers can generate it. This makes clones faster.

Mozilla has implemented similar functionality of this patch on
hg.mozilla.org using a custom extension. We are hosting bundle files in
Amazon S3 and CloudFront (a CDN) and have successfully offloaded
>1 TB/day in data transfer from hg.mozilla.org, freeing up significant
bandwidth and CPU resources. The positive impact has been stellar and
I believe it has proved its value to be included in Mercurial core. I
feel it is important for the client-side support to be enabled in core
by default because it means that clients will get faster, more reliable
clones and will enable server operators to reduce load without
requiring any client-side configuration changes (assuming clients are
up to date, of course).

The scope of this feature is narrowly and specifically tailored to
cloning, despite "serve pulls from pre-generated bundles" being a valid
and useful feature. I would eventually like for Mercurial servers to
support transferring *all* repository data via statically hosted files.
You could imagine a server that siphons all pushed data to bundle files
and instructs clients to apply a stream of bundles to reconstruct all
repository data. This feature, while useful and powerful, is
significantly more work to implement because it requires the server
component have awareness of discovery and a mapping of which changesets
are in which files. Full, clone bundles, by contrast, are much simpler.

The wire protocol command is named "clonebundles" instead of something
more generic like "staticbundles" to leave the door open for a new, more
powerful and more generic server-side component with minimal backwards
compatibility implications. The name "bundleclone" is used by Mozilla's
extension and would cause problems since there are subtle differences
in Mozilla's extension.

Mozilla's experience with this idea has taught us that some form of
"content negotiation" is required. Not all clients will support all
bundle formats or even URLs (advanced TLS requirements, etc). To ensure
the highest uptake possible, a server needs to advertise multiple
versions of bundles and clients need to be able to choose the most
appropriate from that list one. The "attributes" in each
server-advertised entry facilitate this filtering and sorting. Their
use will become apparent in subsequent patches.

Initial inspiration and credit for the idea of cloning from static files
belongs to Augie Fackler and his "lookaside clone" extension proof of
concept.

Setting up test

  $ hg init test
  $ cd test
  $ echo 0 > afile
  $ hg add afile
  $ hg commit -m "0.0"
  $ echo 1 >> afile
  $ hg commit -m "0.1"
  $ echo 2 >> afile
  $ hg commit -m "0.2"
  $ echo 3 >> afile
  $ hg commit -m "0.3"
  $ hg update -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo 1 >> afile
  $ hg commit -m "1.1"
  created new head
  $ echo 2 >> afile
  $ hg commit -m "1.2"
  $ echo "a line" > fred
  $ echo 3 >> afile
  $ hg add fred
  $ hg commit -m "1.3"
  $ hg mv afile adifferentfile
  $ hg commit -m "1.3m"
  $ hg update -C 3
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg mv afile anotherfile
  $ hg commit -m "0.3m"
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions
  $ cd ..
  $ hg init empty

Bundle and phase

  $ hg -R test phase --force --secret 0
  $ hg -R test bundle phase.hg empty
  searching for changes
  no changes found (ignored 9 secret changesets)
  [1]
  $ hg -R test phase --draft -r 'head()'

Bundle --all

  $ hg -R test bundle --all all.hg
  9 changesets found

Bundle test to full.hg

  $ hg -R test bundle full.hg empty
  searching for changes
  9 changesets found

Unbundle full.hg in test

  $ hg -R test unbundle full.hg
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 4 files
  (run 'hg update' to get a working copy)

Verify empty

  $ hg -R empty heads
  [1]
  $ hg -R empty verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions

Pull full.hg into test (using --cwd)

  $ hg --cwd test pull ../full.hg
  pulling from ../full.hg
  searching for changes
  no changes found

Verify that there are no leaked temporary files after pull (issue2797)

  $ ls test/.hg | grep .hg10un
  [1]

Pull full.hg into empty (using --cwd)

  $ hg --cwd empty pull ../full.hg
  pulling from ../full.hg
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Rollback empty

  $ hg -R empty rollback
  repository tip rolled back to revision -1 (undo pull)

Pull full.hg into empty again (using --cwd)

  $ hg --cwd empty pull ../full.hg
  pulling from ../full.hg
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Pull full.hg into test (using -R)

  $ hg -R test pull full.hg
  pulling from full.hg
  searching for changes
  no changes found

Pull full.hg into empty (using -R)

  $ hg -R empty pull full.hg
  pulling from full.hg
  searching for changes
  no changes found

Rollback empty

  $ hg -R empty rollback
  repository tip rolled back to revision -1 (undo pull)

Pull full.hg into empty again (using -R)

  $ hg -R empty pull full.hg
  pulling from full.hg
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Log -R full.hg in fresh empty

  $ rm -r empty
  $ hg init empty
  $ cd empty
  $ hg -R bundle://../full.hg log
  changeset:   8:aa35859c02ea
  tag:         tip
  parent:      3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3m
  
  changeset:   7:a6a34bfa0076
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3m
  
  changeset:   6:7373c1169842
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3
  
  changeset:   5:1bb50a9436a7
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.2
  
  changeset:   4:095197eb4973
  parent:      0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.1
  
  changeset:   3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3
  
  changeset:   2:e38ba6f5b7e0
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.2
  
  changeset:   1:34c2bf6b0626
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.1
  
  changeset:   0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.0
  
Make sure bundlerepo doesn't leak tempfiles (issue2491)

  $ ls .hg
  00changelog.i
  cache
  requires
  store

Pull ../full.hg into empty (with hook)

  $ echo "[hooks]" >> .hg/hgrc
  $ echo "changegroup = printenv.py changegroup" >> .hg/hgrc

doesn't work (yet ?)

hg -R bundle://../full.hg verify

  $ hg pull bundle://../full.hg
  pulling from bundle:../full.hg
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  changegroup hook: HG_NODE=f9ee2f85a263049e9ae6d37a0e67e96194ffb735 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=bundle:../full.hg (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Rollback empty

  $ hg rollback
  repository tip rolled back to revision -1 (undo pull)
  $ cd ..

Log -R bundle:empty+full.hg

  $ hg -R bundle:empty+full.hg log --template="{rev} "; echo ""
  8 7 6 5 4 3 2 1 0 

Pull full.hg into empty again (using -R; with hook)

  $ hg -R empty pull full.hg
  pulling from full.hg
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  changegroup hook: HG_NODE=f9ee2f85a263049e9ae6d37a0e67e96194ffb735 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=bundle:empty+full.hg (glob)
  (run 'hg heads' to see heads, 'hg merge' to merge)

Create partial clones

  $ rm -r empty
  $ hg init empty
  $ hg clone -r 3 test partial
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg clone partial partial2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd partial

Log -R full.hg in partial

  $ hg -R bundle://../full.hg log -T phases
  changeset:   8:aa35859c02ea
  tag:         tip
  phase:       draft
  parent:      3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3m
  
  changeset:   7:a6a34bfa0076
  phase:       draft
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3m
  
  changeset:   6:7373c1169842
  phase:       draft
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3
  
  changeset:   5:1bb50a9436a7
  phase:       draft
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.2
  
  changeset:   4:095197eb4973
  phase:       draft
  parent:      0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.1
  
  changeset:   3:eebf5a27f8ca
  phase:       public
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3
  
  changeset:   2:e38ba6f5b7e0
  phase:       public
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.2
  
  changeset:   1:34c2bf6b0626
  phase:       public
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.1
  
  changeset:   0:f9ee2f85a263
  phase:       public
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.0
  

Incoming full.hg in partial

  $ hg incoming bundle://../full.hg
  comparing with bundle:../full.hg
  searching for changes
  changeset:   4:095197eb4973
  parent:      0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.1
  
  changeset:   5:1bb50a9436a7
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.2
  
  changeset:   6:7373c1169842
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3
  
  changeset:   7:a6a34bfa0076
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3m
  
  changeset:   8:aa35859c02ea
  tag:         tip
  parent:      3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3m
  

Outgoing -R full.hg vs partial2 in partial

  $ hg -R bundle://../full.hg outgoing ../partial2
  comparing with ../partial2
  searching for changes
  changeset:   4:095197eb4973
  parent:      0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.1
  
  changeset:   5:1bb50a9436a7
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.2
  
  changeset:   6:7373c1169842
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3
  
  changeset:   7:a6a34bfa0076
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3m
  
  changeset:   8:aa35859c02ea
  tag:         tip
  parent:      3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3m
  

Outgoing -R does-not-exist.hg vs partial2 in partial

  $ hg -R bundle://../does-not-exist.hg outgoing ../partial2
  abort: *../does-not-exist.hg* (glob)
  [255]
  $ cd ..

hide outer repo
  $ hg init

Direct clone from bundle (all-history)

  $ hg clone full.hg full-clone
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -R full-clone heads
  changeset:   8:aa35859c02ea
  tag:         tip
  parent:      3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3m
  
  changeset:   7:a6a34bfa0076
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1.3m
  
  $ rm -r full-clone

When cloning from a non-copiable repository into '', do not
recurse infinitely (issue2528)

  $ hg clone full.hg ''
  abort: empty destination path is not valid
  [255]

test for https://bz.mercurial-scm.org/216

Unbundle incremental bundles into fresh empty in one go

  $ rm -r empty
  $ hg init empty
  $ hg -R test bundle --base null -r 0 ../0.hg
  1 changesets found
  $ hg -R test bundle --base 0    -r 1 ../1.hg
  1 changesets found
  $ hg -R empty unbundle -u ../0.hg ../1.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

View full contents of the bundle
  $ hg -R test bundle --base null -r 3  ../partial.hg
  4 changesets found
  $ cd test
  $ hg -R ../../partial.hg log -r "bundle()"
  changeset:   0:f9ee2f85a263
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.0
  
  changeset:   1:34c2bf6b0626
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.1
  
  changeset:   2:e38ba6f5b7e0
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.2
  
  changeset:   3:eebf5a27f8ca
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0.3
  
  $ cd ..

test for 540d1059c802

test for 540d1059c802

  $ hg init orig
  $ cd orig
  $ echo foo > foo
  $ hg add foo
  $ hg ci -m 'add foo'

  $ hg clone . ../copy
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tag foo

  $ cd ../copy
  $ echo >> foo
  $ hg ci -m 'change foo'
  $ hg bundle ../bundle.hg ../orig
  searching for changes
  1 changesets found

  $ cd ../orig
  $ hg incoming ../bundle.hg
  comparing with ../bundle.hg
  searching for changes
  changeset:   2:ed1b79f46b9a
  tag:         tip
  parent:      0:bbd179dfa0a7
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change foo
  
  $ cd ..

test bundle with # in the filename (issue2154):

  $ cp bundle.hg 'test#bundle.hg'
  $ cd orig
  $ hg incoming '../test#bundle.hg'
  comparing with ../test
  abort: unknown revision 'bundle.hg'!
  [255]

note that percent encoding is not handled:

  $ hg incoming ../test%23bundle.hg
  abort: repository ../test%23bundle.hg not found!
  [255]
  $ cd ..

test to bundle revisions on the newly created branch (issue3828):

  $ hg -q clone -U test test-clone
  $ cd test

  $ hg -q branch foo
  $ hg commit -m "create foo branch"
  $ hg -q outgoing ../test-clone
  9:b4f5acb1ee27
  $ hg -q bundle --branch foo foo.hg ../test-clone
  $ hg -R foo.hg -q log -r "bundle()"
  9:b4f5acb1ee27

  $ cd ..

test for https://bz.mercurial-scm.org/1144

test that verify bundle does not traceback

partial history bundle, fails w/ unknown parent

  $ hg -R bundle.hg verify
  abort: 00changelog.i@bbd179dfa0a7: unknown parent!
  [255]

full history bundle, refuses to verify non-local repo

  $ hg -R all.hg verify
  abort: cannot verify bundle or remote repos
  [255]

but, regular verify must continue to work

  $ hg -R orig verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 2 changesets, 2 total revisions

diff against bundle

  $ hg init b
  $ cd b
  $ hg -R ../all.hg diff -r tip
  diff -r aa35859c02ea anotherfile
  --- a/anotherfile	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,4 +0,0 @@
  -0
  -1
  -2
  -3
  $ cd ..

bundle single branch

  $ hg init branchy
  $ cd branchy
  $ echo a >a
  $ echo x >x
  $ hg ci -Ama
  adding a
  adding x
  $ echo c >c
  $ echo xx >x
  $ hg ci -Amc
  adding c
  $ echo c1 >c1
  $ hg ci -Amc1
  adding c1
  $ hg up 0
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo b >b
  $ hg ci -Amb
  adding b
  created new head
  $ echo b1 >b1
  $ echo xx >x
  $ hg ci -Amb1
  adding b1
  $ hg clone -q -r2 . part

== bundling via incoming

  $ hg in -R part --bundle incoming.hg --template "{node}\n" .
  comparing with .
  searching for changes
  1a38c1b849e8b70c756d2d80b0b9a3ac0b7ea11a
  057f4db07f61970e1c11e83be79e9d08adc4dc31

== bundling

  $ hg bundle bundle.hg part --debug --config progress.debug=true
  query 1; heads
  searching for changes
  all remote heads known locally
  2 changesets found
  list of changesets:
  1a38c1b849e8b70c756d2d80b0b9a3ac0b7ea11a
  057f4db07f61970e1c11e83be79e9d08adc4dc31
  bundling: 1/2 changesets (50.00%)
  bundling: 2/2 changesets (100.00%)
  bundling: 1/2 manifests (50.00%)
  bundling: 2/2 manifests (100.00%)
  bundling: b 1/3 files (33.33%)
  bundling: b1 2/3 files (66.67%)
  bundling: x 3/3 files (100.00%)

== Test for issue3441

  $ hg clone -q -r0 . part2
  $ hg -q -R part2 pull bundle.hg
  $ hg -R part2 verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 3 changesets, 5 total revisions

  $ cd ..