Implement this function on `RemoteRepository`, and move `repositories`
to the trait level.
This function will be used to quickly get the `RefsAt` of all repository
remotes.
There are two areas where we can be more tolerant of delegate namespaces
being missing or not validating:
1. Calculating the canonical HEAD
2. Fetching from a remote
In 1. the protocol is tolerant in that if the local node does not have
the default branch for a delegate, it will still attempt to use any of
the delegates it does have to reach the threshold.
This is made safe by ensuring that if the threshold is being updated
then the node performing the update must have a threshold of delegates
locally in their storage. It also made safe by 2.
In 2. the protocol is tolerant by allowing delegates to be missing
from the serving side, as long as they can still meet a threshold of
delegates. This is further tolerant, when validating the received
data, a threshold of delegates are valid to consider the fetch
successful -- otherwise it will fail.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
When deciding whether or not to fetch a repo based on a refs
announcement, we need to know whether our signed refs are stale or not,
compared to the ones in the announcement. This can be quite expensive as
it requires multiple reads from Git's ODB, which often results in
packfile loading.
To remedy this, we introduce a refs cache in our node database that is
consulted when an announcement is received.
We also remove the logic that generates `info` messages, since they are
rarely needed and introduced more complexity.
Additionally, we revert commit 3ad2b4431f,
which introduced logic to minimze wants and haves with additional logic,
since it potentially also increases the load on the ODB.
This change limits the amount of `wants` and `haves` data that is sent
to the serving side of a fetch.
When a `RefsAt` announcement is sent, the fetching peer can calculate
the difference between the `rad/sigrefs` they're aware of -- if it
exists -- and the newly advertised `rad/sigrefs`. This means they can
efficiently ask for the `wants` and `haves` of references that have
changed -- saving some data sent over to the serving side.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
The protocol requires that the fetcher signals to the remote that it
is done with the fetching process, so that the remote can exit out of
its upload-pack process.
The first change is that the `done` signal can happen before the
validation, since nothing else needs to be fetched.
The second change is that the fetcher does not care if the remote
responds to this signal since it has the data required for validation
and applying the changes to its refdb. Thus, if an error is
encountered then it is logged, but the rest of the process proceeds as
normal.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
When performing a handshake, the error source is hidden in the error
variant and never shown.
To get insight as to what the error was, it is logged when it is
encounterd.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Log when different stages of the fetch have completed, while also
providing the elapsed time, in seconds.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
If an ancestry check of an annotated tag was triggered then the fetch
from that peer would fail. This is due to `graph_ahead_behind` only
working for commit-ish objects.
To allow for annotated tags, and other object that peel to commits,
the check now peels the two objects to commits before getting their
`Oid`s. The call to `graph_ahead_behind` can take these two `Oid`s
instead.
A test for annotated tags is included as part of the `examples/git`
suite in the CLI tests.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
The following scenario was noticed:
If a node has a `rad/id` that is behind the one it is fetching from,
where a delegate was added, then verification will fail since it will
not fetch the new delegate -- if the scope is set to `Followed`.
Irregardless if the `rad/id` is ahead or behind, the reference should
be fetched to use as the delegates anchor since it will tell the
fetching side which delegates in can fetch from the remote. If any of
those delegates are missing then the remote is indeed lying.
This is safe since the `refs/rad/id` reference is only updated by
computing the COB rather than setting the OID, so it will not update
through the fetch protocol itself.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Update to git2-0.18.1, which also requires updating radicle-git-ext
and radicle-surf.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
If a delegate is missing the default branch for a project certain
computations will fail, e.g. getting the canonical mainline branch.
One prevention for corrupting data is refusing to fetch a delegate
that does not have the default branch, when the repository is a
project. It is assumed that the repository is not a project if calling
`Doc::project` returns an error, since the error variants are not
found and parsing errors.
This is only checked in the case of a delegate since non-delegates are
safe to created COBs that don't require the default branch,
e.g. creating an issue.
The pack-writer perfectly consumes all input of the pack without
overshoot, which it can as it knows how many objects it ought
to read.
Thus, the last packetline of the pack is consumed to the last
byte without ever asking for more data that would then be denied
as the flush packet is encountered.
This needs to be accounted for in the calling code.
Signed-off-by: Sebastian Thiel <sebastian.thiel@icloud.com>
Ref announcements contain the namespace (NID) and the SHA of the new
`rad/sigrefs`. This information can be used by the fetch protocol to
fetch only those `Oid`s for those namespaces.
Add a new stage `SigrefsAnnouncement` that captures this behaviour by
only asking for the advertised `Oid`s and updating the corresponding
`rad/sigrefs` for each namespace. Note that this is a special case of
the `SpecialRefs` stage and so the protocol chooses between these two
by checking if there was announcement passed through. The following
stage, `DataRefs`, stays the same.
Note that this stage can only be activated via a `pull`, and `clone`
stays the same.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Add debugging code for inspecting the in-memory Refdb of the Cache.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Previously, if a delegate's namespace was fetched and its rad/sigrefs
was behind the current state, then it would fail to perform the fetch.
Instead, when the ancestry path is checked the outcome can be used
during the update:
1. If the tip is equal, then the update can be marked as skipped.
2. If the tip is behind, then the update can be rejected, iff the
policy does not allow it.
3. If the tip is ahead, then the update is a fast-forward.
4. If the tip is diverged, then the update results in a failure, iff
the policy does not allow it.
The protocol also prunes any delegates's updates when the `rad/sigrefs`
is behind and returns an error if they are diverged.
For any non-delegates, it will simply prune them.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
The `radicle-fetch` crate introduces a method for fetching from a
server using Git protocol V2, which provides the implementation
control over performing a sequence of fetches and validation over
domain data.
The protocol is built on top of the suite of Gitoxide crates[[0]]. It
builds wrappers on top of Gitoxide's refdb, odb, and transport layers
-- as well as taking the ls-refs and fetch code straight from the code
base to simplify for the needs of this crate.
[0]: https://github.com/Byron/gitoxide
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
cloudhead
Fintan Halpenny
Lars Wirzenius
Sebastian Thiel