Fermi docs example broken

[keflavich]

The example in the Fermi tutorial doesn't work:

In [22]: from astroquery import fermi

In [23]: query = fermi.FermiLAT_Query()
ERROR: TypeError: __call__() takes at least 2 arguments (1 given) [IPython.core.interactiveshell]
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-23-6470dbf3fa96> in <module>()
----> 1 query = fermi.FermiLAT_Query()

TypeError: __call__() takes at least 2 arguments (1 given)

@jdnc Can you re-factor Fermi soon (see #112)?
If not I might have time to do it next week.

[keflavich]

@cdeil: @jdnc has started a new grad program, so she will be unable to work on this prior to the release, I suspect.

However, I've started on it; if you want to add some work, could you issue PRs on this PR:
#182

[kialio]

I just posted this on an enrico thread but putting it here since it might be useful information. We're (as in the Fermi SSC) are happy this is here but one thing to note: We've had a few cases in the past year of users not thinking through the scripting process and submitting 100's (and one time 1000's) of queries in less than a minute. This pretty much looks like a dds attack and overwhelms our servers. We've implemented checks for this and block IPs that do it. I'm not sure if you can implement something in astroquery that prohibits this kind of behavior but if you can, that would be good. Not sure if the over zealous users are using astroquery or not. Probably just using homegrown tools.

In the end, if a user wants to submit 1000's of queries, it would be more efficient for the user to grab the weekly files instead. These are updated as fast as the data in the data server. ie. the most recent weekly file might not be a full week, it just includes the most recent data.

[keflavich]

@kialio Thanks for letting me know! This raises an issue I just keep forgetting about: we should have all requests posted to any server explicitly identify astroquery as the source of the query, that way server managers know to come to us.

Anyway, we shouldn't be pinging your servers directly much - our tests no longer require communications with external servers. We can put warnings in place to try to prevent users from submitting excessive queries, but for better or worse, the queries actually are incredibly simple, so there's nothing to prevent a user from submitting a request in a for loop or something stupid like that.

That said, the Astroquery FERMI code was basically totally nonfunctional prior to a few weeks ago, so we weren't at fault for those other silly users.

[cdeil]

@kialio If you have a suggestion what restriction would make sense to put in astroquery.fermi to make it hard for users to accidentally query too much (or intentionally make many queries, but get IP-banned as a resut) please let us know or make a PR.