68 lines
2.5 KiB
Markdown
68 lines
2.5 KiB
Markdown
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# Writing custom modules
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Custom filters are Python files written in `/etc/pyruse/pyruse/filters/`.
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Custom actions are Python files written in `/etc/pyruse/pyruse/actions/`.
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Filters must define a class named `Filter` that extends Pyruse’s own `Filter` class from the `pyruse.base` namespace.
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By convention, a filter module name starts with `filter_`. A filter module looks like this:
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```python
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from pyruse import base
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class Filter(base.Filter):
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def __init__(self, args):
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super().__init__()
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# get mandatory arguments with args["param_name"]
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# get optional arguments with args.get("param_name", default_value)
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# store in self.whatever the data that is needed at each run of filter below
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def filter(self, entry):
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# return true for the "then" link, or false for the "else" link
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return some_check(entry["a_field"], entry["another_field"])
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```
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Actions must define a class named `Action` that extends Pyruse’s own `Action` class from the `pyruse.base` namespace.
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By convention, an action module name starts with `action_`. An action module looks like this:
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```python
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from pyruse import base
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class Action(base.Action):
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def __init__(self, args):
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super().__init__()
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# get mandatory arguments with args["param_name"]
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# get optional arguments with args.get("param_name", default_value)
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# store in self.whatever the data that is needed at each run of act below
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def act(self, entry):
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# do whatever this action is supposed to do
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```
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Some actions may need to restore a state at boot, or each time the main Pyruse program is restarted. The aim usually is to configure an external tool (firewall, etc.), based on files, or a database…
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In such cases:
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* The action’s constructor must be altered so that it does not fail if `args` is `None`:
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```python
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def __init__(self, args):
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super().__init__()
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if args is None:
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return
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```
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* A new `boot` method must be defined; it will get called at boot and this is where the wanted state shall be restored:
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```python
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def boot(self):
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# do whatever must be done
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```
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* Assuming the action is named `action_myModule`, the systemd unit `pyruse-boot@action_myModule.service` should be enabled. If this unit has dependencies, these must be declared before enabling the specific `pyruse-boot` service, by creating a drop-in with the dependencies, for example:
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```
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# /etc/systemd/system/pyruse-boot@action_myModule.service.d/action_myModule.conf
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[Unit]
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Requires=iptables.service
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After=iptables.service
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```
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