Add pool size parameter to client constructor

[ikovalkovskyi]

This pull request relates to the issue Connection pool is full, discarding connection. To reproduce it you need to create more than 10 (default size of the urllib3 connection pool) simultaneous connection to the database from the same client object.

[xginn8]

I think it makes sense to cast this value to an int, like we do for the port parameter in line 81.

[ikovalkovskyi]

@xginn8 makes sense.

[ikovalkovskyi]

@xginn8 nice catch!

[xginn8]

thanks for contributing!

[hppylbb]

Hi all, sorry but I find this issue is still exist in the master branch, the parameter pool_size is invalid even we added it to __init__ method. I think that

influxdb-python/influxdb/client.py

Line 106 in 35732cd

self._session.mount(self._scheme, adapter)

should be modified to "self._session.mount(self._scheme+'://', adapter)",
because after executing this line, the "session.adapters" will have three members: "OrderedDict([('https://', <requests.adapters.HTTPAdapter object at 0x7f0c9c123890>), ('http://', <requests.adapters.HTTPAdapter object at 0x7f0c9404e190>), ('http', <requests.adapters.HTTPAdapter object at 0x7f0c9e874290>)]))", the https:// and http:// adapters are added here https://github.com/requests/requests/blob/3dc84cde5b785a85cb20eb2f0d4530fd568a6af7/requests/sessions.py#L391-L393 while initializing, and when you execute https://github.com/requests/requests/blob/3dc84cde5b785a85cb20eb2f0d4530fd568a6af7/requests/sessions.py#L691, you want to get the adapter 'http' which is mounted at

influxdb-python/influxdb/client.py

Line 106 in 35732cd

self._session.mount(self._scheme, adapter)

(the third one in OrderedDict), but here you got a incorrect adapter which is http:// (the second one in OrderedDict), this adapter doesn't contain the 'pool_size' parameter we added to __init__ method while initializing InfluxDBClient.

So while we write_points to influxdb, we still use the default pool_size=10, then we run into issue #349.

If we add '://' to self._session.mount(self._scheme+'://', adapter), then the OrderedDict will only contains two adapters: OrderedDict([('https://', <requests.adapters.HTTPAdapter object at 0x7f0c9c123890>), ('http://', <requests.adapters.HTTPAdapter object at 0x7f0c9404e190>)]), the http:// adapter will be overrided by our session mount method, then we can get the correct http adapter with the pool_size we added.

Sorry but I am a newbee of github, cc @xginn8 @vaniakov for notification this comment.

[ikovalkovskyi]

@hppylbb you are correct. Working on the new PR.