git-annex/doc/todo/git-annex_proxies.mdwn
2024-06-25 17:50:22 -04:00

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This is a summary todo covering several subprojects, which would extend
git-annex to be able to use proxies which sit in front of a cluster of
repositories.
1. [[design/passthrough_proxy]]
2. [[design/p2p_protocol_over_http]]
3. [[design/balanced_preferred_content]]
4. [[todo/track_free_space_in_repos_via_git-annex_branch]]
5. [[todo/proving_preferred_content_behavior]]
Joey has received funding to work on this.
Planned schedule of work:
* June: git-annex proxy
* July, part 1: git-annex proxy support for exporttree
* July, part 2: p2p protocol over http
* August: balanced preferred content
* September: streaming through proxy to special remotes (especially S3)
* October: proving behavior of balanced preferred content with proxies
[[!tag projects/openneuro]]
# work notes
In development on the `proxy` branch.
For June's work on [[design/passthrough_proxy]], remaining todos:
* Since proxying to special remotes is not supported yet, and won't be for
the first release, make it fail in a reasonable way.
* Support distributed clusters: Make a proxy for a cluster repeat
protocol messages on to any remotes that have the same UUID as
the cluster. Needs VIA extension to P2P protocol to avoid cycles.
* Getting a key from a cluster currently always selects the lowest cost
remote, and always the same remote if cost is the same. Should
round-robin amoung remotes, and prefer to avoid using remotes that
other git-annex processes are currently using.
* Optimise proxy speed. See design for ideas.
* Use `sendfile()` to avoid data copying overhead when
`receiveBytes` is being fed right into `sendBytes`.
Library to use:
<https://hackage.haskell.org/package/hsyscall-0.4/docs/System-Syscall.html>
* Encryption and chunking. See design for issues.
* Indirect uploads (to be considered). See design.
* Support using a proxy when its url is a P2P address.
(Eg tor-annex remotes.)
* `viconfig` support for setting preferred content, group,
and description of clusters
# completed items for June's work on [[design/passthrough_proxy]]:
* UUID discovery via git-annex branch. Add a log file listing UUIDs
accessible via proxy UUIDs. It also will contain the names
of the remotes that the proxy is a proxy for,
from the perspective of the proxy. (done)
* Add `git-annex updateproxy` command (done)
* Remote instantiation for proxies. (done)
* Implement git-annex-shell proxying to git remotes. (done)
* Proxy should update location tracking information for proxied remotes,
so it is available to other users who sync with it. (done)
* Implement `git-annex updatecluster` command (done)
* Implement cluster UUID insertation on location log load, and removal
on location log store. (done)
* Omit cluster UUIDs when constructing drop proofs, since lockcontent will
always fail on a cluster. (done)
* Don't count cluster UUID as a copy in numcopies checking etc. (done)
* Tab complete proxied remotes and clusters in eg --from option. (done)
* Getting a key from a cluster should proxy from one of the nodes that has
it. (done)
* Implement upload with fanout to multiple cluster nodes and reporting back
additional UUIDs over P2P protocol. (done)
* Implement cluster drops, trying to remove from all nodes, and returning
which UUIDs it was dropped from. (done)
* `git-annex testremote` works against proxied remote and cluster. (done)
* Avoid `git-annex sync --content` etc from operating on cluster nodes by
default since syncing with a cluster implicitly syncs with its nodes. (done)
* On upload to cluster, send to nodes where its preferred content, and not
to other nodes. (done)
* Support annex.jobs for clusters. (done)