monitoring software with api/service to pull data

[Aljoša Mohorović]

i'm looking for software that provides things like nagios (my current
option) but provides an API or some kind of service (rest, soap, ...)
which would enable me to retrieve data using some programming language
(preferably python).
few examples:
- "get data for all network traffic via http"
- "get data for all network traffic via http that was requested for
domain example.com"
- "get data for all network traffic via http that was requested for
domain example.com in time frame 1/1/2008 - 1/2/2008"

what i'm looking for is some software that does system monitoring and
alerting stuff but also provides high level api/service to retrieve
data useful for creating reports.
any ideas? or should i stick with nagios and use nagios options?

Aljosa Mohorovic