How to clean Agent process?

Questions / Help
1

I do start a process in agent, like this for example:

{:ok, pid} = Agent.start_link( fn -> stream end, name: {:global, String.to_atom(process_name)})

I want to clean the process and free the registered name too, How would I clean that process ? as I have registered it globally {:global, String.to_atom(process_name)} ?

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2

Agent.stop sounds the most logical. The name will be unregistered automatically, it doesn’t matter if the process is stopped nicely, killed, crashed, etc.

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3

Precisely, if the process dies in any way, the name dies too. :slight_smile:

4

Thanks! I thought the name will be pointing to a null reference, cool Elixir :slight_smile:

5

Is this the right way to use stop ?

Agent.stop({:global, process_name});

where {:global, process_name} were used in the first place of creating the agent:

{:ok, pid} = Agent.start_link( fn -> stream end, name: {:global, process_name})

correct?

6

If you go here: https://hexdocs.pm/elixir/Agent.html#stop/3

Then click on the “agent” link in the type definition, it will bring you to the definition of that type, which does include the :global tuple (as one of the possible values for name). So yes, it should be fine.

You can double check out that the process was unregistered by calling :global.whereis_name(process_name). This returns a pid iff the process is globally registered. You may also find Process.alive?(pid) interesting.

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7

Ah, thanks for the tip on doc, :global.whereis_name(process_name) is just what I need.

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8

If you are curious, by ‘naming a pid’ with a tuple like {:global, :blahname} you are saying to register it with the :global module and it is what handles monitoring, auto-unregistering, etc
 You can make and use your own custom registration service, say named :blahglobal and use it like {:via, :blahglobal, :blahname}. :slight_smile:

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9

I am new to Elixir, I don’t know if I will need or why I would need to have my own custom registration service, at least, I know how to register an agent and recall it now :slight_smile:

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