I need to parse dhcpd.leases to store data in mysql
dhcp1 at thehobsons.co.uk
Fri Jun 30 07:03:15 UTC 2006
Sébastien CRAMATTE wrote:
>But how do you parse the lease ?
In basic terms, you read the file and parse
what's in it ! You've already been given an
example in Perl that will do it. I doubt if
anyone has something they can share with you,
because not many people do it, and it's probably
that no-one has done exactly what you are after.
There's a bit more to it than that though.
Because of the way that dhcp works, if you just
parse the file every hour or so, there is a
chance that you could miss some intermediate log
records. If you parse it every few minutes, then
you vastly reduce that opportunity to miss
things, but you will spend a lot of time just
re-parsing what you've already done. Either way
you will need to handle the case where records
already exist, so the database operations become
Which is right for you depends on what you want
to achieve. Do you want to capture every detail
with minimum latency, or are you happy to just
get an overview that could be an hour or two old ?
For minimum latency and maximum 'resolution', I'd
be considering a loop that reads the leases file
and then waits when it gets to the end so that it
can read further records as they are added (like
"tail -f" does). You will need to watch for when
the file moves and becomes the backup file, at
which point you'll need to start over.
For minimum overhead whilst still capturing
everything, watch for the backup file changing
and then process it. This will give you
everything the server did in the previous hour.
If you don't care about processing overhead, just
parse the leases file (or the backup file) every
so often. Run the program from cron, and it's the
simplest way to do it.
You basic process will need to be something like :
read a record and parse it
is it a record type we're interested in
- if not then skip
does it already exist in the database
- if yes, then update the record if required
- else add the record
until you run out of data
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