Fix the AccessLoggingFilter

[LucaCinquini]

Who: Luca

It has been reported that in a small percentage of the cases, data downloads are not completed successfully because of the AccessLoogingFilter. What is wrong in the AccessLoggingFilter is unknown.

[LucaCinquini]

I have created a new version of the AccessLoggingFilter (with the same name) which does the following:

o Does NOT wrap the HTTP response to count the bytes actually transferred, in case this is the source of the problem
o Does NOT rely in esg.ini to check the size of the file on disk for every request/response, in case this is the source of the problem. This also has the additional benefit the data downloads will NOT crash if the file mounting point is NOT found in the esg.ini file (as it happened previously)

The new filter also does the following:

o Retrieves the size of the input file from the HTTP response "Content-Length" (same as the TDS does)
o Retrieves the "duration" time (time to deliver the response) from the filter execution time - same as the TDS servlet does
o Logs the original URL that was requested, i.e. it does NOT strip the first part of the URL to try a resolution with the mount point in the file system
o Sets success=true if the response code is 200 (NOTE: the response code will be 200 even if the client interrupts the request. It will NOT be 200 if a problem arises on the server side).

[LucaCinquini]

This has been tested successfully at JPL after loading 356452 entries in the esgf_node_manager.access_logging table. But is is possible that problems arise only for large database tables and high concurrency situations.

[LucaCinquini]

Example of entry for restricted download:

select user_id, url, remote_addr, user_agent, service_type, batch_update_time, to_timestamp(date_fetched), success, duration, user_idp, data_size, xfer_size, duration from esgf_node_manager.access_logging order by date_fetched desc limit 1;
user_id | url | remote_addr | user_agent | serv
ice_type | batch_update_time | to_timestamp | success | duration | user_idp | data_size | xfer_size | duration
----------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------+-----
---------+-------------------+------------------------+---------+----------+------------------------+-----------+-----------+----------
https://esgf-node.jpl.nasa.gov/esgf-idp/openid/rootAdmin | https://esgf-dev.jpl.nasa.gov/thredds/fileServer/esg_dataroot/obs4MIPs/observations/atmos/hus/mon/grid/NASA-JPL/MLS/v20111025/hus_MLS_L3_v03-3x_200408-201012.nc | 137.79.241.180 | | thre
dds | 0 | 2016-03-14 09:43:31-07 | t | 20033 | esgf-node.jpl.nasa.gov | 45919888 | -1 | 20033
(1 row)