Prevent unnecessary cache invalidation

We use 2 scheduled actions with a high frequency:
- check conversion queue (every 2 minutes)
- unlock folders (every 10 minutes)

The issue is that the job processing triggers a cache invalidation which
impacts performances.

The conversion queue is now dynamically activated when we run a
converter. It is automatically deactivated once a day if no converter is
running.

The folder unlocking is now executed every 3 hours. Indeed, the 'Unlock'
button is now made more visible, so it can be done maunally. We still
keep the cron to avoid the library not being scanned for ages.

data/oomusic_converter_data.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <odoo>
     <data noupdate="1">
-        <!-- Cron to build image cache -->
+        <!-- Cron to launch conversion -->
         <record id="oomusic_convert" model="ir.cron">
             <field name="name">oomusic.convert</field>
             <field name="active" eval="True"/>
@@ -14,5 +14,19 @@
             <field name="state">code</field>
             <field name="code">model.cron_convert()</field>
         </record>
+
+        <!-- Cron to deactivate above cron -->
+        <record id="oomusic_convert_toggle" model="ir.cron">
+            <field name="name">oomusic.convert.toggle</field>
+            <field name="active" eval="True"/>
+            <field name="user_id" ref="base.user_root"/>
+            <field name="interval_number">1</field>
+            <field name="interval_type">days</field>
+            <field name="numbercall">-1</field>
+            <field name="doall" eval="False"/>
+            <field name="model_id" ref="oomusic.model_oomusic_converter"/>
+            <field name="state">code</field>
+            <field name="code">model.cron_toggle()</field>
+        </record>
     </data>
 </odoo>

data/oomusic_folder_data.xml

@@ -36,8 +36,8 @@
             <field name="name">oomusic.unlock.folder</field>
             <field name="active" eval="True"/>
             <field name="user_id" ref="base.user_root"/>
-            <field name="interval_number">10</field>
-            <field name="interval_type">minutes</field>
+            <field name="interval_number">3</field>
+            <field name="interval_type">hours</field>
             <field name="numbercall">-1</field>
             <field name="doall" eval="False"/>
             <field name="model_id" ref="oomusic.model_oomusic_folder"/>

models/oomusic_converter.py

@@ -184,6 +184,11 @@ def action_run(self):
             {"state": "waiting"}
         )
 
+        # Activate the cron if necessary
+        cron = self.env.ref("oomusic.oomusic_convert", raise_if_not_found=False)
+        if cron and not cron.active:
+            cron.try_write({"active": True})
+
     def action_draft(self):
         self.write({"state": "draft"})
         self.env["oomusic.converter.line"].search([("converter_id", "in", self.ids)]).write(
@@ -210,6 +215,15 @@ def action_convert(self):
     def cron_convert(self):
         self.search([("state", "=", "running")]).action_convert()
 
+    def cron_toggle(self):
+        # Deactivate the cron automatically if there is no job running. This prevents unnecessary
+        # cache clearing.
+        if not self.sudo().search([("state", "=", "running")]):
+            cron = self.env.ref("oomusic.oomusic_convert", raise_if_not_found=False)
+            if cron and cron.active:
+                cron.try_write({"active": False})
+            return
+
 
 class MusicConverterLine(models.Model):
     _name = "oomusic.converter.line"