[PATCH v2 00/36] Promisor remotes and external ODB support

This is a follow up from an early patch series at the beginning of the year that started to integrate the jh/fsck-promisors patch series with the external odb patch series.

A lot of things are different because the jh/fsck-promisors and jh/partial-clone have been merged into master since the v1. So the integration is much more complete now (though not fully complete), and this integration happens quite early in the patch series.

This integration makes it possible to have many promisor and partial clone remotes (instead of just one) with possibly different partial clone filters, though that is not tested yet.

I am not sure that the "external odb" name is still the best, as the promisor remotes are not quite external. So I am open to suggestions about a new name.

This patch series does not include the last part of the original external odb series which was about adding an `--inital-refspec` option to `git clone`, as this might not be needed anymore and this current series is long and complex enough.

High level overview of this patch series ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In general the external odb tests are now numbered 05XX instead of 04XX, so that they don't conflict with promisor objects/partial clone tests. Also there are a lot of changes since v1, so I don't think an interdiff would be useful.

  - Patches 1/36 to 12/36:
  
These patches implement the external odb infrastructure as well as the
support for promisor objects and partial clone.

  - Patches 13/36 and 14/36:

These patches move over the promisor objects and partial clone code to use the external odb mechanism. The result of 13/36 is that instead of the "extensions.partialclone" config variable, a "odb.<name>.promisorRemote" config variable is now used. The result of 14/36 is that instead of the "core.partialclonefilter" config variable, a "odb.<name>.partialclonefilter" config variable is now used.

  - Patches 15/36 to 36/36:

These patches implement the rest of the external odb mechanism. Patch 36/36 is a documentation patch that explains how this mechanism work, though this patch needs to be updated.

Future work ~~~~~~~~~~~

  - add tests that show that one can now use more than one promisor remote
  - add fsck, gc and repack tests for script and process modes
  - see if partial clone filters could be used for other modes
  - update documentation patch
  - fix memory leaks
  - take another look at prepare_helper_command() [1]
  - take a look at changing the order of the have object lines [1]
  - take a look at what happens when a server creates a pack [2]
  - add tests with different kinds of external odbs

[1] https://public-inbox.org/git/ebf67bcc-3e17-3fda-9f56-dd152e7bf3af@jeffhostetler.com/ [2] https://public-inbox.org/git/8de3597a-01bd-a721-fffb-20769701d0af@jeffhostetler.com/

Links ~~~~~

This patch series on GitHub:

https://github.com/chriscool/git/commits/gl-small-promisor-external-odb-next

Peff started to work on external odbs some years ago:

http://thread.gmane.org/gmane.comp.version-control.git/206886/focus=207040 http://thread.gmane.org/gmane.comp.version-control.git/247171 http://thread.gmane.org/gmane.comp.version-control.git/202902/focus=203020

His work, which is not compile-tested any more:

https://github.com/peff/git/commits/jk/external-odb-wip

Initial discussions about external odbs:

http://thread.gmane.org/gmane.comp.version-control.git/288151/focus=295160

Version 1, 2, 3, 4, 5 and 6 of the external odbs series:

https://public-inbox.org/git/20160613085546.11784-1-chriscool@tuxfamily.org/ https://public-inbox.org/git/20160628181933.24620-1-chriscool@tuxfamily.org/ https://public-inbox.org/git/20161130210420.15982-1-chriscool@tuxfamily.org/ https://public-inbox.org/git/20170620075523.26961-1-chriscool@tuxfamily.org/ https://public-inbox.org/git/20170803091926.1755-1-chriscool@tuxfamily.org/ https://public-inbox.org/git/20170916080731.13925-1-chriscool@tuxfamily.org/

Some of the discussions related to Ben Peart's work that is used by this series:

https://public-inbox.org/git/20170113155253.1644-1-benpeart@microsoft.com/ https://public-inbox.org/git/20170322165220.5660-1-benpeart@microsoft.com/ https://public-inbox.org/git/20170714132651.170708-1-benpeart@microsoft.com/

Version 1, 2, 3, 4, 5 and 6 of the external odbs series on GitHub:

https://github.com/chriscool/git/commits/gl-external-odb12 https://github.com/chriscool/git/commits/gl-external-odb22 https://github.com/chriscool/git/commits/gl-external-odb61 https://github.com/chriscool/git/commits/gl-external-odb239 https://github.com/chriscool/git/commits/gl-external-odb373 https://github.com/chriscool/git/commits/gl-external-odb411

Version 1 of this "Promisor remotes and external ODB support" series:

https://public-inbox.org/git/20180103163403.11303-1-chriscool@tuxfamily.org/

Version 1 of this "Promisor remotes and external ODB support" series on GitHub:

https://github.com/chriscool/git/commits/gl-small-promisor-external-odb12

Ben Peart (1):
  Add t0550 to test 'get_direct' mechanism

Christian Couder (35):
  Add initial external odb support
  sha1_file: add prepare_external_alt_odb()
  Add GIT_NO_EXTERNAL_ODB env variable
  external-odb: add has_external_odb()
  external-odb: implement external_odb_get_direct
  sha1_file: prepare for external odbs
  odb-helper: add 'enum odb_helper_type'
  external-odb: add external_odb_reinit()
  external-odb: add script mode support
  odb-helper: add 'script_mode' to 'struct odb_helper'
  odb-helper: add odb_helper_init() to send 'init' instruction
  external-odb: add external_odb_get_many_direct()
  Use external_odb_get_direct() and has_external_odb()
  Use odb.origin.partialclonefilter instead of core.partialclonefilter
  external-odb: add 'get_direct' support
  t0500: add 'put_raw_obj' instruction to odb-helper script
  external odb: add 'put_raw_obj' support
  external-odb: accept only blobs for now
  t0500: add test for external odb write support
  Add t0510 to test external ODB transfer
  lib-httpd: pass config file to start_httpd()
  lib-httpd: add upload.sh
  lib-httpd: add list.sh
  lib-httpd: add apache-e-odb.conf
  odb-helper: add odb_helper_get_raw_object()
  pack-objects: don't pack objects in external odbs
  Add t0520 to test transfer to HTTP external odb
  odb-helper: add init_object_process()
  Add t0560 to test passing git objects
  odb-helper: add put_object_process()
  Add t0570 to test passing raw objects
  odb-helper: add have_object_process()
  Add t0580 to test "have" capability and raw objects
  external-odb: use 'odb=magic' attribute to mark odb blobs
  Add Documentation/technical/external-odb.txt

 Documentation/technical/external-odb.txt |  342 +++++++
 Makefile                                 |    2 +
 builtin/cat-file.c                       |    5 +-
 builtin/fetch.c                          |   13 +-
 builtin/gc.c                             |    3 +-
 builtin/pack-objects.c                   |    4 +
 builtin/repack.c                         |    3 +-
 cache.h                                  |   20 +-
 connected.c                              |    3 +-
 environment.c                            |    5 +-
 external-odb.c                           |  250 +++++
 external-odb.h                           |   25 +
 list-objects-filter-options.c            |   46 +-
 list-objects-filter-options.h            |    3 +-
 odb-helper.c                             | 1109 ++++++++++++++++++++++
 odb-helper.h                             |   49 +
 packfile.c                               |    3 +-
 setup.c                                  |    7 +-
 sha1_file.c                              |  120 ++-
 t/lib-httpd.sh                           |    8 +-
 t/lib-httpd/apache-e-odb.conf            |  214 +++++
 t/lib-httpd/list.sh                      |   41 +
 t/lib-httpd/upload.sh                    |   45 +
 t/t0410-partial-clone.sh                 |   30 +-
 t/t0500-external-odb.sh                  |   83 ++
 t/t0510-transfer-e-odb.sh                |  147 +++
 t/t0520-transfer-http-e-odb.sh           |  145 +++
 t/t0550-read-object.sh                   |   28 +
 t/t0550/read-object                      |   68 ++
 t/t0560-read-object-git.sh               |   28 +
 t/t0560/read-object-git                  |   78 ++
 t/t0570-read-object-http-e-odb.sh        |  112 +++
 t/t0570/read-object-plain                |   83 ++
 t/t0580-read-object-have-http-e-odb.sh   |  112 +++
 t/t0580/read-object-plain-have           |  103 ++
 t/t5500-fetch-pack.sh                    |    4 +-
 t/t5601-clone.sh                         |    2 +-
 t/t5616-partial-clone.sh                 |    4 +-
 unpack-trees.c                           |    6 +-
 39 files changed, 3254 insertions(+), 99 deletions(-)
 create mode 100644 Documentation/technical/external-odb.txt
 create mode 100644 external-odb.c
 create mode 100644 external-odb.h
 create mode 100644 odb-helper.c
 create mode 100644 odb-helper.h
 create mode 100644 t/lib-httpd/apache-e-odb.conf
 create mode 100644 t/lib-httpd/list.sh
 create mode 100644 t/lib-httpd/upload.sh
 create mode 100755 t/t0500-external-odb.sh
 create mode 100755 t/t0510-transfer-e-odb.sh
 create mode 100755 t/t0520-transfer-http-e-odb.sh
 create mode 100755 t/t0550-read-object.sh
 create mode 100755 t/t0550/read-object
 create mode 100755 t/t0560-read-object-git.sh
 create mode 100755 t/t0560/read-object-git
 create mode 100755 t/t0570-read-object-http-e-odb.sh
 create mode 100755 t/t0570/read-object-plain
 create mode 100755 t/t0580-read-object-have-http-e-odb.sh
 create mode 100755 t/t0580/read-object-plain-have