Problem: pause and rescheduler jobs (serialized and deserialized obviously)

Structure

A TGJob tg_job is a telegram job and is based on a constructor with 5 args and a APScheduler Job job field

• tg_job = TGJob(callback, data, name, chat_id, user_id): the actual callback, data, ecc we set
• tg_job.job =APJob(callback=tg_job.run, args[application], name=name, **job_kwargs)

So the TGJob wraps the APjob setting the application (became the bot context) as parameter for the tg_job.run function when the callback will be executed.

Serialization

APScheduler so will try to serialize the job instance but application is a arg so it would have been serialized. Here we have our implementation of SQLAlchemyJobStore in jobstore.py.

Adapter of SQLAlchemyJobStore

When a job is going to be serialized we:

• copy the job
• get the tg_job instantiating the self of the job callback (tg_job.run remember?) if the tg_job is in memory
• settings the job args to tg_job parameters [callback, data, name, chat_id, user_id] so replacing the unique [application] arg.

then the job is serialized, remember with these key fields:

• callback = tg_job.run function literal (reference to the function not the instance obiouvsly)
• args = [callback, data, name, chat_id, user_id]

Deserialization

When we want to reschedule or pause an existing job, we get the job:

• job deserialized
• create a tg_job = TGGob(job.args) (5 args)
• modify the job args to be 2 (not only application now). tg_job and application. The first is going to be the self argument, the second is the standard application argument that we started with before serialization

Serialization of a deserialized job

When we come to the serialization step this time we do not have a tg_job instance when trying to get the self from the job.callback function literal. __self__ does not exists.

Solution

So get the tg_job form the first argument we provided during deserialization that is the instance we need :)