Documentation unclear on proper extended usage of WriteApi client

[markmnl]

Does the WriteAPI client support context management? If so what does the context manager do - flush, close, wait for batch to complete? I cannot answer any of these queststions reading the doucmentation so I don't know if I should be creating a new instance of WriteApi client evey time I want to write a new batch..

Important: The WriteApi in batching mode (default mode) is suppose to run as a singleton. To flush all your data you should call _write_client.close() at the end of your script.

This part of the documentation I find contradictory - singleton implies never create another instance - but it goes on to say I should close to flush?? What if I have a service continuously running? How can I flush what has already been written if I want to? I don't feel confident reading the documentation using this library...

[bednar]

Hi @markmnl,

thanks for your comment.

Does the WriteAPI client support context management?

Currently not, but It is a good suggestion 👍 and we will add support for this.

If so what does the context manager do - flush, close, wait for batch to complete?

I think the context manager will close the WriteApi.

What if I have a service continuously running? How can I flush what has already been written if I want to?

Currently We don’t have an explicit flush method. 😞. I will take a look too.

Anyway thanks for your comment!

Regards

[lafrech]

Hi.

A context manager would be really nice indeed.

It is also unclear to me the difference between write_api.close() and write_api.__del__().

Are the three following lines needed?

    write_api.close()
    write_api.__del__()
    client.__del__()

I didn't dive into the internals but it sounds very strange to call __del__ like this on an object. I never to that in Python as it should be done automatically by the garbage collector.

I wouldn't find it strange if I had to call a flush method manually, though.

Also, if close or __del__ forces the flush of the write_api, how come we also need to call __del __ on client? Is there anything else to flush?

In any case, a proper context manager should take care of all this.

[lafrech]

Answering myself (partly).

For both InfluxDBClient and WriteApi, the close method is just a wrapper around __del__.

influxdb-client-python/influxdb_client/client/write_api.py

Lines 263 to 265 in a3e18ee

	def close(self):
	"""Flush data and dispose a batching buffer."""
	self.__del__()

influxdb-client-python/influxdb_client/client/influxdb_client.py

Lines 165 to 167 in 5eb4cdf

	def close(self):
	"""Shutdown the client."""
	self.__del__()

I guess we should use close, then, and the docs should advertise the use of close.

Definitely something nice hiding in a context manager.