dovecot - Dec 2011 - doveadm + dsync merging

doveadm already supports some nice things, such as being able to remotely launch
a doveadm command via TCP socket. It also supports executing a command for all
users or to some specific users using a wildcard. dsync could use these
features, so I merged dsync and doveadm into same binary for v2.1.

I'll still install "dsync" symlink pointing to
"doveadm", and running that way it should be fully backwards
compatible with the old dsync binary and its parameters.

I'm mainly now wondering about the command naming for running dsync via
doveadm. Any suggestions?

a) Use "doveadm dsync" prefix, and otherwise keep the names same:

dsync mirror -> doveadm dsync mirror
dsync backup -> doveadm dsync backup
dsync server -> doveadm dsync server (for running dsync remotely via
ssh/etc.)

b) Don't have the dsync prefix:

dsync mirror -> doveadm mirror
dsync backup -> doveadm backup
dsync server -> doveadm dsync-server (could be hidden from the doveadm
commands list)

c) Either a) or b), but rename "mirror" to "sync" or
"dsync" or "replicate"?

d) Something else?

* Timo Sirainen <dovecot at dovecot.org>:
> doveadm already supports some nice things, such as being able to remotely
launch a doveadm command via TCP socket. It also supports executing a command
for all users or to some specific users using a wildcard. dsync could use these
features, so I merged dsync and doveadm into same binary for v2.1.
> 
> I'll still install "dsync" symlink pointing to
"doveadm", and running that way it should be fully backwards
compatible with the old dsync binary and its parameters.
> 
> I'm mainly now wondering about the command naming for running dsync via
doveadm. Any suggestions?
> 
> a) Use "doveadm dsync" prefix, and otherwise keep the names same:
> 
> dsync mirror -> doveadm dsync mirror
> dsync backup -> doveadm dsync backup
> dsync server -> doveadm dsync server (for running dsync remotely via
ssh/etc.)
> 
> b) Don't have the dsync prefix:
> 
> dsync mirror -> doveadm mirror
> dsync backup -> doveadm backup
> dsync server -> doveadm dsync-server (could be hidden from the doveadm
commands list)
Calling the old "dsync" command (symlink) directly should keep the
already
established command structure.

Calling dsync features over doveadm should keep command structure as simple
(not complex) as possible. I favour b) for that and rename 'mirror' to
'sync'.

'sync' keeps in line with products such as rsync. People will
immediately know
what it does.

p at rick

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Hi,

On 12/29/2011 01:35 PM, Timo Sirainen wrote:
> doveadm already supports some nice things, such as being able to remotely
launch a doveadm command via TCP socket. It also supports executing a command
for all users or to some specific users using a wildcard. dsync could use these
features, so I merged dsync and doveadm into same binary for v2.1.
>
> I'll still install "dsync" symlink pointing to
"doveadm", and running that way it should be fully backwards
compatible with the old dsync binary and its parameters.
>
> I'm mainly now wondering about the command naming for running dsync via
doveadm. Any suggestions?
>
> a) Use "doveadm dsync" prefix, and otherwise keep the names same:
>
> dsync mirror ->  doveadm dsync mirror
> dsync backup ->  doveadm dsync backup
> dsync server ->  doveadm dsync server (for running dsync remotely via
ssh/etc.)
>
> b) Don't have the dsync prefix:
>
> dsync mirror ->  doveadm mirror
> dsync backup ->  doveadm backup
> dsync server ->  doveadm dsync-server (could be hidden from the doveadm
commands list)
>
> c) Either a) or b), but rename "mirror" to "sync" or
"dsync" or "replicate"?
>
> d) Something else?
>
Slightly different, but it would be good to have a persistently running 
daemon which could operate both in server and client mode.
In server mode it would listen on a TCP socket. In client mode it would 
accept source and target information via a control socket. The target IP 
address and port would be the daemon's listening socket.

Something like this on the server side:
service dsync {
   process_limit = 8
   client_limit = 8
   inet_listener dsync {
     port = 5555
   }

Then doveadm sync on the "client) could first connect to the local 
server (client), which then connects to the remote service on the 
server. Eg.:
doveadm sync [-C <alt char>] [-m <mailbox>] [-u <user>]
[-frRv]
   mirror <local mail_location> | [<user>@]<host>
where user at host should specify the remote user (mailbox user) and host 
should read like 1.1.1.1:1234 (IP address|hostname and port where the 
dsync service listens. Or a separate port option to allow easier parsing.

Having the client in a persistent setup would allow faster syncs for 
repeated invocations. It would be good to have a simple API to trigger 
the sync (a simple text protocol on a unix socket, or something) from 
outside programs, to avoid calling doveadm.

The next thing would be to follow dovecot logs and do a sync/async 
replication. :)