view tests/test-phases.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.

  $ hglog() { hg log --template "{rev} {phaseidx} {desc}\n" $*; }
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    message="$1"
  >    shift
  >    hg ci -m "$message" $*
  > }

  $ hg init initialrepo
  $ cd initialrepo

Cannot change null revision phase

  $ hg phase --force --secret null
  abort: cannot change null revision phase
  [255]
  $ hg phase null
  -1: public

  $ mkcommit A

New commit are draft by default

  $ hglog
  0 1 A

Following commit are draft too

  $ mkcommit B

  $ hglog
  1 1 B
  0 1 A

Draft commit are properly created over public one:

  $ hg phase --public .
  $ hg phase
  1: public
  $ hglog
  1 0 B
  0 0 A

  $ mkcommit C
  $ mkcommit D

  $ hglog
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test creating changeset as secret

  $ mkcommit E --config phases.new-commit='secret'
  $ hglog
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test the secret property is inherited

  $ mkcommit H
  $ hglog
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Even on merge

  $ hg up -q 1
  $ mkcommit "B'"
  created new head
  $ hglog
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A
  $ hg merge 4 # E
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg phase
  6: draft
  4: secret
  $ hg ci -m "merge B' and E"
  $ hglog
  7 2 merge B' and E
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A

Test secret changeset are not pushed

  $ hg init ../push-dest
  $ cat > ../push-dest/.hg/hgrc << EOF
  > [phases]
  > publish=False
  > EOF
  $ hg outgoing ../push-dest --template='{rev} {phase} {desc|firstline}\n'
  comparing with ../push-dest
  searching for changes
  0 public A
  1 public B
  2 draft C
  3 draft D
  6 draft B'
  $ hg outgoing -r 'branch(default)' ../push-dest --template='{rev} {phase} {desc|firstline}\n'
  comparing with ../push-dest
  searching for changes
  0 public A
  1 public B
  2 draft C
  3 draft D
  6 draft B'

  $ hg push ../push-dest -f # force because we push multiple heads
  pushing to ../push-dest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  $ hglog
  7 2 merge B' and E
  6 1 B'
  5 2 H
  4 2 E
  3 1 D
  2 1 C
  1 0 B
  0 0 A
  $ cd ../push-dest
  $ hglog
  4 1 B'
  3 1 D
  2 1 C
  1 0 B
  0 0 A

(Issue3303)
Check that remote secret changeset are ignore when checking creation of remote heads

We add a secret head into the push destination. This secret head shadows a
visible shared between the initial repo and the push destination.

  $ hg up -q 4 # B'
  $ mkcommit Z --config phases.new-commit=secret
  $ hg phase .
  5: secret

We now try to push a new public changeset that descend from the common public
head shadowed by the remote secret head.

  $ cd ../initialrepo
  $ hg up -q 6 #B'
  $ mkcommit I
  created new head
  $ hg push ../push-dest
  pushing to ../push-dest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

:note: The "(+1 heads)" is wrong as we do not had any visible head

check that branch cache with "served" filter are properly computed and stored

  $ ls ../push-dest/.hg/cache/branch2*
  ../push-dest/.hg/cache/branch2-served
  $ cat ../push-dest/.hg/cache/branch2-served
  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default
  $ hg heads -R ../push-dest --template '{rev}:{node} {phase}\n'  #update visible cache too
  6:6d6770faffce199f1fddd1cf87f6f026138cf061 draft
  5:2713879da13d6eea1ff22b442a5a87cb31a7ce6a secret
  3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e draft
  $ ls ../push-dest/.hg/cache/branch2*
  ../push-dest/.hg/cache/branch2-served
  ../push-dest/.hg/cache/branch2-visible
  $ cat ../push-dest/.hg/cache/branch2-served
  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default
  $ cat ../push-dest/.hg/cache/branch2-visible
  6d6770faffce199f1fddd1cf87f6f026138cf061 6
  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e o default
  2713879da13d6eea1ff22b442a5a87cb31a7ce6a o default
  6d6770faffce199f1fddd1cf87f6f026138cf061 o default


Restore condition prior extra insertion.
  $ hg -q --config extensions.mq= strip .
  $ hg up -q 7
  $ cd ..

Test secret changeset are not pull

  $ hg init pull-dest
  $ cd pull-dest
  $ hg pull ../initialrepo
  pulling from ../initialrepo
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 5 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hglog
  4 0 B'
  3 0 D
  2 0 C
  1 0 B
  0 0 A
  $ cd ..

But secret can still be bundled explicitly

  $ cd initialrepo
  $ hg bundle --base '4^' -r 'children(4)' ../secret-bundle.hg
  4 changesets found
  $ cd ..

Test secret changeset are not cloned
(during local clone)

  $ hg clone -qU initialrepo clone-dest
  $ hglog -R clone-dest
  4 0 B'
  3 0 D
  2 0 C
  1 0 B
  0 0 A

Test summary

  $ hg summary -R clone-dest --verbose
  parent: -1:000000000000  (no revision checked out)
  branch: default
  commit: (clean)
  update: 5 new changesets (update)
  $ hg summary -R initialrepo
  parent: 7:17a481b3bccb tip
   merge B' and E
  branch: default
  commit: (clean) (secret)
  update: 1 new changesets, 2 branch heads (merge)
  phases: 3 draft, 3 secret
  $ hg summary -R initialrepo --quiet
  parent: 7:17a481b3bccb tip
  update: 1 new changesets, 2 branch heads (merge)

Test revset

  $ cd initialrepo
  $ hglog -r 'public()'
  0 0 A
  1 0 B
  $ hglog -r 'draft()'
  2 1 C
  3 1 D
  6 1 B'
  $ hglog -r 'secret()'
  4 2 E
  5 2 H
  7 2 merge B' and E

test that phase are displayed in log at debug level

  $ hg log --debug
  changeset:   7:17a481b3bccb796c0521ae97903d81c52bfee4af
  tag:         tip
  phase:       secret
  parent:      6:cf9fe039dfd67e829edf6522a45de057b5c86519
  parent:      4:a603bfb5a83e312131cebcd05353c217d4d21dde
  manifest:    7:5e724ffacba267b2ab726c91fc8b650710deaaa8
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      C D E
  extra:       branch=default
  description:
  merge B' and E
  
  
  changeset:   6:cf9fe039dfd67e829edf6522a45de057b5c86519
  phase:       draft
  parent:      1:27547f69f25460a52fff66ad004e58da7ad3fb56
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    6:ab8bfef2392903058bf4ebb9e7746e8d7026b27a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      B'
  extra:       branch=default
  description:
  B'
  
  
  changeset:   5:a030c6be5127abc010fcbff1851536552e6951a8
  phase:       secret
  parent:      4:a603bfb5a83e312131cebcd05353c217d4d21dde
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    5:5c710aa854874fe3d5fa7192e77bdb314cc08b5a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      H
  extra:       branch=default
  description:
  H
  
  
  changeset:   4:a603bfb5a83e312131cebcd05353c217d4d21dde
  phase:       secret
  parent:      3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    4:7173fd1c27119750b959e3a0f47ed78abe75d6dc
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      E
  extra:       branch=default
  description:
  E
  
  
  changeset:   3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  phase:       draft
  parent:      2:f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    3:6e1f4c47ecb533ffd0c8e52cdc88afb6cd39e20c
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      D
  extra:       branch=default
  description:
  D
  
  
  changeset:   2:f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  phase:       draft
  parent:      1:27547f69f25460a52fff66ad004e58da7ad3fb56
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    2:66a5a01817fdf5239c273802b5b7618d051c89e4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      C
  extra:       branch=default
  description:
  C
  
  
  changeset:   1:27547f69f25460a52fff66ad004e58da7ad3fb56
  phase:       public
  parent:      0:4a2df7238c3b48766b5e22fafbb8a2f506ec8256
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    1:cb5cbbc1bfbf24cc34b9e8c16914e9caa2d2a7fd
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      B
  extra:       branch=default
  description:
  B
  
  
  changeset:   0:4a2df7238c3b48766b5e22fafbb8a2f506ec8256
  phase:       public
  parent:      -1:0000000000000000000000000000000000000000
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    0:007d8c9d88841325f5c6b06371b35b4e8a2b1a83
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      A
  extra:       branch=default
  description:
  A
  
  


(Issue3707)
test invalid phase name

  $ mkcommit I --config phases.new-commit='babar'
  transaction abort!
  rollback completed
  abort: phases.new-commit: not a valid phase name ('babar')
  [255]
Test phase command
===================

initial picture

  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 public B
  |
  o  0 public A
  

display changesets phase

(mixing -r and plain rev specification)

  $ hg phase 1::4 -r 7
  1: public
  2: draft
  3: draft
  4: secret
  7: secret


move changeset forward

(with -r option)

  $ hg phase --public -r 2
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

move changeset backward

(without -r option)

  $ hg phase --draft --force 2
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 secret E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 public B
  |
  o  0 public A
  

move changeset forward and backward and test kill switch

  $ cat <<EOF >> $HGRCPATH
  > [experimental]
  > nativephaseskillswitch = true
  > EOF
  $ hg phase --draft --force 1::4
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 secret merge B' and E
  |\
  | o  6 draft B'
  | |
  +---o  5 secret H
  | |
  o |  4 draft E
  | |
  o |  3 draft D
  | |
  o |  2 draft C
  |/
  o  1 draft B
  |
  o  0 public A
  
test partial failure

  $ cat <<EOF >> $HGRCPATH
  > [experimental]
  > nativephaseskillswitch = false
  > EOF
  $ hg phase --public 7
  $ hg phase --draft '5 or 7'
  cannot move 1 changesets to a higher phase, use --force
  phase changed for 1 changesets
  [1]
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    7 public merge B' and E
  |\
  | o  6 public B'
  | |
  +---o  5 draft H
  | |
  o |  4 public E
  | |
  o |  3 public D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

test complete failure

  $ hg phase --draft 7
  cannot move 1 changesets to a higher phase, use --force
  no phases changed
  [1]

  $ cd ..

test hidden changeset are not cloned as public (issue3935)

  $ cd initialrepo

(enabling evolution)
  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF

(making a changeset hidden; H in that case)
  $ hg debugobsolete `hg id --debug -r 5`

  $ cd ..
  $ hg clone initialrepo clonewithobs
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 7 changesets with 6 changes to 6 files
  updating to branch default
  6 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clonewithobs
  $ hg log -G --template "{rev} {phase} {desc}\n"
  @    6 public merge B' and E
  |\
  | o  5 public B'
  | |
  o |  4 public E
  | |
  o |  3 public D
  | |
  o |  2 public C
  |/
  o  1 public B
  |
  o  0 public A
  

test verify repo containing hidden changesets, which should not abort just
because repo.cancopy() is False

  $ cd ../initialrepo
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 8 changesets, 7 total revisions