Implement
* pruning on source side
* local job
* test subcommand for doing a dry-run of a prune policy
* use a non-blocking callback from autosnap to trigger the depending
jobs -> avoids races, looks saner in the debug log
Done:
* implement autosnapper that asserts interval between snapshots
* implement pruner
* job pull: pulling + pruning
* job source: autosnapping + serving
TODO
* job source: pruning
* job local: everything
* fatal errors such as serve that cannot bind socket must be more
visible
* couldn't things that need a snapshotprefix just use a interface
Prefixer() instead? then we could have prefixsnapshotfilter and not
duplicate it every time...
* either go full context.Context or not at all...? just wait because
community climate around it isn't that great and we only need it for
cancellation? roll our own?
How it works:
`zrepl stdinserver CLIENT_IDENTITY`
* connects to the socket in $global.serve.stdinserver.sockdir/CLIENT_IDENTITY
* sends its stdin / stdout file descriptors to the `zrepl daemon` process (see cmsg(3))
* does nothing more
This enables a setup where `zrepl daemon` is not directly exposed to the
internet but instead all traffic is tunnelled through SSH.
The server with the source job has an authorized_keys file entry for the
public key used by the corresponding pull job
command="/mnt/zrepl stdinserver CLIENT_IDENTITY" ssh-ed25519 AAAAC3NzaC1E... zrepl@pullingserver
Tear down occurs on each protocol level, stack-wise.
Open RWC
Open ML (with NewMessageLayer)
Open RPC (with NewServer/ NewClient)
Close RPC (with Close() from Client())
Close ML
* in Server: after error / receive of Close request
* in Client: after getting ACK for Close request from Server
Close RWC
To achieve this, a DataType for RPC control messages was added, which
has a separate set of endpoints. Not exactly pretty, but works for now.
The necessity of the RST frame remains to be determined. However, it is
nice to have a way to signal the other side something went terribly
wrong in the middle of an operation. Example: A frameBridingWriter fails
to read the next chunk of a file it is supposed to send, it can just
send an RST frame to signal this operation failed... Wouldn't trailers
make sense then?
Don't use jobrun for daemon, just call JobDo() once, the job must
organize stuff itself.
Sacrifice all the oneshot commands, they will be reintroduced as
client-calls to the daemon.
