logmsg: added HOSTID

[lbudai]

HOSTID is a 32-bit number generated by a cryptographically secure PRNG.
Its purpose is to identify the syslog-ng host, thus it is the same for
every message of the host. It can be accessed via the $HOSTID macro.

HOSTID is stored in the persist file (if the persist file
removed, new HOSTID will be generated).

Example config:
source s_local {
tcp(
ip("127.0.0.1")
port(10514)
);
};

template t_hostid {
template("msg:$MSG hostid:$HOSTID\n");
};

destination d_file {
file("/tmp/hostid.ose.log" template(t_hostid));
};

log {
source(s_local);
destination(d_file);
};

example value:
msg:xxx hostid:5ec829c3

Signed-off-by: Budai Laszlo Laszlo.Budai@balabit.com

[lbudai]

OpenSSL is needed by hostid (this is why Travis failed).

We have two choices:

• hostid will be available only when OpenSSL is enabled
• enable using OpenSSL by default
  .

[bazsi]

I would enable openssl as mandatory, what do you think @algernon?

[algernon]

Does "enable by default" mean no way to turn it off? I'd advise against that (doesn't affect Debian, or most distros, but still). If it means highly recommended, on by default and errors out if not present, unless explicitly disabled - that is perfectly ok.

[bazsi]

Macros are implemented in the core. In order to make this optional we'd
need to make macros pluggable, or use weak linking tricks to see if openssl
is available.

Again, we need openssl for generating random numbers in a portable way.
Uuid is another such case.
On Dec 9, 2014 8:14 AM, "Gergely Nagy" notifications@github.com wrote:

Does "enable by default" mean no way to turn it off? I'd advise against
that (doesn't affect Debian, or most distros, but still). If it means
highly recommended, on by default and errors out if not present, unless
explicitly disabled - that is perfectly ok.

—
Reply to this email directly or view it on GitHub
#337 (comment).

[algernon]

After a good nights sleep, I'm inclined to say to just depend on OpenSSL. It's not worth the trouble to try supporting a very uncommon case.

[bazsi]

@lbudai we seem to have reached conclusion. Could you merge this?

I see that Travis failed, thats probably because the dependency needs to be added.

[lbudai]

@bazsi: I will merge soon
created a separate branch for setting OpenSSL as a hard dependency
(reason of the separate branch is that if we have OpenSSL then -I think- we should build all SSL dependent features by default -> #368 )

[lbudai]

After #368 is merged f/hostid branch is rebased to current master, now waiting for Travis.

If everything goes well, I'll push the merge button.

[bazsi]

This seems green now.