tests/test-clonebundles.t

clonebundles: filter on bundle specification

Not all clients are capable of reading every bundle. Currently, content
negotiation to ensure a server sends a client a compatible bundle
format is performed at request time. The response bundle is dynamically
generated at request time, so this works fine.

Clone bundles are statically generated *before* the request. This means
that a modern server could produce bundles that a legacy client isn't
capable of reading. Without some kind of "type hint" in the clone
bundles manifest, a client may attempt to download an incompatible
bundle. Furthermore, a client may not realize a bundle is incompatible
until it has processed part of the bundle (imagine consuming a 1 GB
changegroup bundle2 part only to discover the bundle2 part afterwards is
incompatibl). This would waste time and resources. And it isn't very
user friendly.

Clone bundle manifests thus need to advertise the *exact* format of the
hosted bundles so clients may filter out entries that they don't know
how to read. This patch introduces that mechanism.

We introduce the BUNDLESPEC attribute to declare the "bundle
specification" of the entry. Bundle specifications are parsed using
exchange.parsebundlespecification, which uses the same strings as the
"--type" argument to `hg bundle`. The supported bundle specifications
are well defined and backwards compatible.

When a client encounters a BUNDLESPEC that is invalid or unsupported, it
silently ignores the entry.

Set up a server

  $ hg init server
  $ cd server
  $ cat >> .hg/hgrc << EOF
  > [extensions]
  > clonebundles =
  > EOF

  $ touch foo
  $ hg -q commit -A -m 'add foo'
  $ touch bar
  $ hg -q commit -A -m 'add bar'

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

Feature disabled by default
(client should not request manifest)

  $ hg clone -U http://localhost:$HGPORT feature-disabled
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files

  $ cat server/access.log
  * - - [*] "GET /?cmd=capabilities HTTP/1.1" 200 - (glob)
  * - - [*] "GET /?cmd=batch HTTP/1.1" 200 - x-hgarg-1:cmds=heads+%3Bknown+nodes%3D (glob)
  * - - [*] "GET /?cmd=getbundle HTTP/1.1" 200 - x-hgarg-1:bundlecaps=HG20%2Cbundle2%3DHG20%250Achangegroup%253D01%252C02%250Adigests%253Dmd5%252Csha1%252Csha512%250Aerror%253Dabort%252Cunsupportedcontent%252Cpushraced%252Cpushkey%250Ahgtagsfnodes%250Alistkeys%250Apushkey%250Aremote-changegroup%253Dhttp%252Chttps&cg=1&common=0000000000000000000000000000000000000000&heads=aaff8d2ffbbf07a46dd1f05d8ae7877e3f56e2a2&listkeys=phase%2Cbookmarks (glob)
  * - - [*] "GET /?cmd=listkeys HTTP/1.1" 200 - x-hgarg-1:namespace=phases (glob)

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > clonebundles = true
  > EOF

Missing manifest should not result in server lookup

  $ hg --verbose clone -U http://localhost:$HGPORT no-manifest
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files

  $ tail -4 server/access.log
  * - - [*] "GET /?cmd=capabilities HTTP/1.1" 200 - (glob)
  * - - [*] "GET /?cmd=batch HTTP/1.1" 200 - x-hgarg-1:cmds=heads+%3Bknown+nodes%3D (glob)
  * - - [*] "GET /?cmd=getbundle HTTP/1.1" 200 - x-hgarg-1:bundlecaps=HG20%2Cbundle2%3DHG20%250Achangegroup%253D01%252C02%250Adigests%253Dmd5%252Csha1%252Csha512%250Aerror%253Dabort%252Cunsupportedcontent%252Cpushraced%252Cpushkey%250Ahgtagsfnodes%250Alistkeys%250Apushkey%250Aremote-changegroup%253Dhttp%252Chttps&cg=1&common=0000000000000000000000000000000000000000&heads=aaff8d2ffbbf07a46dd1f05d8ae7877e3f56e2a2&listkeys=phase%2Cbookmarks (glob)
  * - - [*] "GET /?cmd=listkeys HTTP/1.1" 200 - x-hgarg-1:namespace=phases (glob)

Empty manifest file results in retrieval
(the extension only checks if the manifest file exists)

  $ touch server/.hg/clonebundles.manifest
  $ hg --verbose clone -U http://localhost:$HGPORT empty-manifest
  no clone bundles available on remote; falling back to regular clone
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files

Manifest file with invalid URL aborts

  $ echo 'http://does.not.exist/bundle.hg' > server/.hg/clonebundles.manifest
  $ hg clone http://localhost:$HGPORT 404-url
  applying clone bundle from http://does.not.exist/bundle.hg
  error fetching bundle: [Errno -2] Name or service not known
  abort: error applying bundle
  (consider contacting the server operator if this error persists)
  [255]

Server is not running aborts

  $ echo "http://localhost:$HGPORT1/bundle.hg" > server/.hg/clonebundles.manifest
  $ hg clone http://localhost:$HGPORT server-not-runner
  applying clone bundle from http://localhost:$HGPORT1/bundle.hg
  error fetching bundle: [Errno 111] Connection refused
  abort: error applying bundle
  (consider contacting the server operator if this error persists)
  [255]

Server returns 404

  $ python $TESTDIR/dumbhttp.py -p $HGPORT1 --pid http.pid
  $ cat http.pid >> $DAEMON_PIDS
  $ hg clone http://localhost:$HGPORT running-404
  applying clone bundle from http://localhost:$HGPORT1/bundle.hg
  HTTP error fetching bundle: HTTP Error 404: File not found
  abort: error applying bundle
  (consider contacting the server operator if this error persists)
  [255]

We can override failure to fall back to regular clone

  $ hg --config ui.clonebundlefallback=true clone -U http://localhost:$HGPORT 404-fallback
  applying clone bundle from http://localhost:$HGPORT1/bundle.hg
  HTTP error fetching bundle: HTTP Error 404: File not found
  falling back to normal clone
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files

Bundle with partial content works

  $ hg -R server bundle --type gzip-v1 --base null -r 53245c60e682 partial.hg
  1 changesets found

We verify exact bundle content as an extra check against accidental future
changes. If this output changes, we could break old clients.

  $ f --size --hexdump partial.hg
  partial.hg: size=208
  0000: 48 47 31 30 47 5a 78 9c 63 60 60 98 17 ac 12 93 |HG10GZx.c``.....|
  0010: f0 ac a9 23 45 70 cb bf 0d 5f 59 4e 4a 7f 79 21 |...#Ep..._YNJ.y!|
  0020: 9b cc 40 24 20 a0 d7 ce 2c d1 38 25 cd 24 25 d5 |..@$ ...,.8%.$%.|
  0030: d8 c2 22 cd 38 d9 24 cd 22 d5 c8 22 cd 24 cd 32 |..".8.$."..".$.2|
  0040: d1 c2 d0 c4 c8 d2 32 d1 38 39 29 c9 34 cd d4 80 |......2.89).4...|
  0050: ab 24 b5 b8 84 cb 40 c1 80 2b 2d 3f 9f 8b 2b 31 |.$....@..+-?..+1|
  0060: 25 45 01 c8 80 9a d2 9b 65 fb e5 9e 45 bf 8d 7f |%E......e...E...|
  0070: 9f c6 97 9f 2b 44 34 67 d9 ec 8e 0f a0 92 0b 75 |....+D4g.......u|
  0080: 41 d6 24 59 18 a4 a4 9a a6 18 1a 5b 98 9b 5a 98 |A.$Y.......[..Z.|
  0090: 9a 18 26 9b a6 19 98 1a 99 99 26 a6 18 9a 98 24 |..&.......&....$|
  00a0: 26 59 a6 25 5a 98 a5 18 a6 24 71 41 35 b1 43 dc |&Y.%Z....$qA5.C.|
  00b0: 96 b0 83 f7 e9 45 8b d2 56 c7 a3 1f 82 52 d7 8a |.....E..V....R..|
  00c0: 78 ed fc d5 76 f1 36 95 dc 05 07 00 ad 39 5e d3 |x...v.6......9^.|

  $ echo "http://localhost:$HGPORT1/partial.hg" > server/.hg/clonebundles.manifest
  $ hg clone -U http://localhost:$HGPORT partial-bundle
  applying clone bundle from http://localhost:$HGPORT1/partial.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  finished applying clone bundle
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Bundle with full content works

  $ hg -R server bundle --type gzip-v2 --base null -r tip full.hg
  2 changesets found

Again, we perform an extra check against bundle content changes. If this content
changes, clone bundles produced by new Mercurial versions may not be readable
by old clients.

  $ f --size --hexdump full.hg
  full.hg: size=408
  0000: 48 47 32 30 00 00 00 0e 43 6f 6d 70 72 65 73 73 |HG20....Compress|
  0010: 69 6f 6e 3d 47 5a 78 9c 63 60 60 90 e5 76 f6 70 |ion=GZx.c``..v.p|
  0020: f4 73 77 75 0f f2 0f 0d 60 00 02 46 06 76 a6 b2 |.swu....`..F.v..|
  0030: d4 a2 e2 cc fc 3c 03 23 06 06 e6 7d 40 b1 4d c1 |.....<.#...}@.M.|
  0040: 2a 31 09 cf 9a 3a 52 04 b7 fc db f0 95 e5 a4 f4 |*1...:R.........|
  0050: 97 17 b2 c9 0c 14 00 02 e6 d9 99 25 1a a7 a4 99 |...........%....|
  0060: a4 a4 1a 5b 58 a4 19 27 9b a4 59 a4 1a 59 a4 99 |...[X..'..Y..Y..|
  0070: a4 59 26 5a 18 9a 18 59 5a 26 1a 27 27 25 99 a6 |.Y&Z...YZ&.''%..|
  0080: 99 1a 70 95 a4 16 97 70 19 28 18 70 a5 e5 e7 73 |..p....p.(.p...s|
  0090: 71 25 a6 a4 28 00 19 40 13 0e ac fa df ab ff 7b |q%..(..@.......{|
  00a0: 3f fb 92 dc 8b 1f 62 bb 9e b7 d7 d9 87 3d 5a 44 |?.....b......=ZD|
  00b0: ac 2f b0 a9 c3 66 1e 54 b9 26 08 a7 1a 1b 1a a7 |./...f.T.&......|
  00c0: 25 1b 9a 1b 99 19 9a 5a 18 9b a6 18 19 00 dd 67 |%......Z.......g|
  00d0: 61 61 98 06 f4 80 49 4a 8a 65 52 92 41 9a 81 81 |aa....IJ.eR.A...|
  00e0: a5 11 17 50 31 30 58 19 cc 80 98 25 29 b1 08 c4 |...P10X....%)...|
  00f0: 37 07 79 19 88 d9 41 ee 07 8a 41 cd 5d 98 65 fb |7.y...A...A.].e.|
  0100: e5 9e 45 bf 8d 7f 9f c6 97 9f 2b 44 34 67 d9 ec |..E.......+D4g..|
  0110: 8e 0f a0 61 a8 eb 82 82 2e c9 c2 20 25 d5 34 c5 |...a....... %.4.|
  0120: d0 d8 c2 dc d4 c2 d4 c4 30 d9 34 cd c0 d4 c8 cc |........0.4.....|
  0130: 34 31 c5 d0 c4 24 31 c9 32 2d d1 c2 2c c5 30 25 |41...$1.2-..,.0%|
  0140: 09 e4 ee 85 8f 85 ff 88 ab 89 36 c7 2a c4 47 34 |..........6.*.G4|
  0150: fe f8 ec 7b 73 37 3f c3 24 62 1d 8d 4d 1d 9e 40 |...{s7?.$b..M..@|
  0160: 06 3b 10 14 36 a4 38 10 04 d8 21 01 5a b2 83 f7 |.;..6.8...!.Z...|
  0170: e9 45 8b d2 56 c7 a3 1f 82 52 d7 8a 78 ed fc d5 |.E..V....R..x...|
  0180: 76 f1 36 25 81 49 c0 ad 30 c0 0e 49 8f 54 b7 9e |v.6%.I..0..I.T..|
  0190: d4 1c 09 00 bb 8d f0 bd                         |........|

  $ echo "http://localhost:$HGPORT1/full.hg" > server/.hg/clonebundles.manifest
  $ hg clone -U http://localhost:$HGPORT full-bundle
  applying clone bundle from http://localhost:$HGPORT1/full.hg
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  finished applying clone bundle
  searching for changes
  no changes found

Entry with unknown BUNDLESPEC is filtered and not used

  $ cat > server/.hg/clonebundles.manifest << EOF
  > http://bad.entry1 BUNDLESPEC=UNKNOWN
  > http://bad.entry2 BUNDLESPEC=xz-v1
  > http://bad.entry3 BUNDLESPEC=none-v100
  > http://localhost:$HGPORT1/full.hg BUNDLESPEC=gzip-v2
  > EOF

  $ hg clone -U http://localhost:$HGPORT filter-unknown-type
  applying clone bundle from http://localhost:$HGPORT1/full.hg
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  finished applying clone bundle
  searching for changes
  no changes found

Automatic fallback when all entries are filtered

  $ cat > server/.hg/clonebundles.manifest << EOF
  > http://bad.entry BUNDLESPEC=UNKNOWN
  > EOF

  $ hg clone -U http://localhost:$HGPORT filter-all
  no compatible clone bundles available on server; falling back to regular clone
  (you may want to report this to the server operator)
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files