API: provide a way for the client to specify the influx server with an url.

[thothothotho]

It is now very convenient to configure a Influx client with a server url. Most Influx client libraries support that.

At the moment, the client API is that:

    def __init__(self,
                 host='localhost',
                 port=8086,
                 username='root',
                 password='root',
                 database=None,
                 ssl=False,
                 verify_ssl=False,
                 timeout=None,
                 retries=3,
                 use_udp=False,
                 udp_port=4444,
                 proxies=None,
                 pool_size=10,
                 path='',
                 cert=None,
                 gzip=False,
                 session=None,
                 headers=None,
                 ):

Since internally, you are essentially building a URL:

https://github.com/influxdata/influxdb-python/blob/c3903dda515d4f7efcb8c55250fd8b75c8446034/influxdb/client.py#L166

You should provide an url argument, that would take precedence over host, port, ...

To not break API compatibility, you could do it this way:

    def __init__(self,
                 url=None,
                 host='localhost',
                 port=8086,
                 username='root',
                 password='root',
                 …
       if url:
           self.__baseurl = url
       else:
            # current logic
            self.__baseurl = "{0}://{1}:{2}{3}".format(
                     self._scheme,
                     self._host,
                     self._port,
                     self._path)

[colindean]

I think InfluxDBClient.from_dsn() meets your needs: https://github.com/influxdata/influxdb-python/blob/2c3d49cb51fd37db494a7785fe645e24f277854c/influxdb/client.py#L221-L259