playbook: Fix sensor installation for Debian 11

Previously it only worked with Debian 10. This commit reflects the
removal of the apt package 'python-pip' in Debian 11 and the change
of the i2c bus number.

playbook/roles/olimex-sensor/files/olimex-sensor-set-sensor-permission.sh

-#!/bin/bash
-
-chgrp slapsoft /dev/i2c-3

playbook/roles/olimex-sensor/tasks/main.yml

 - name: Install apt package dependencies
   apt:
     pkg:
-      - python
-      - python-pip
+      - python3
+      - python3-pip
       - i2c-tools
-      - python-smbus
+      - python3-smbus
     state: present
 
 - name: Install setuptools
   pip:
     name: setuptools
-    executable: pip2
+    executable: pip3
 
 - name: Install bme280
   pip:
     name: bme280
-    executable: pip2
+    executable: pip3
+
+# We need to set a different bus number depending
+# on the debian version. For Debian 12 we may
+# need another number again.
+
+- name: Set bus number for debian bullseye
+  set_fact:
+    i2c_bus_number: 3
+  when: ansible_distribution == 'Debian' and ansible_distribution_release == 'Buster'
+
+- name: Set bus number for debian bullseye
+  set_fact:
+    i2c_bus_number: 2
+  when: ansible_distribution == 'Debian' and ansible_distribution_release == 'bullseye'
 
 - name: Solve python template to read sensor
   template:
@@ -27,8 +41,8 @@
     set_olimex_sensor_permission_path: /usr/bin/olimex-sensor-set-sensor-permission
 
 - name: Move script to grant access to sensor to file path
-  copy:
-    src: olimex-sensor-set-sensor-permission.sh
+  template:
+    src: olimex-sensor-set-sensor-permission.j2
     dest: "{{ set_olimex_sensor_permission_path }}"
     mode: 755
 

playbook/roles/olimex-sensor/templates/olimex-sensor-set-sensor-permission.j2

+#!/bin/bash
+
+chgrp slapsoft /dev/i2c-{{ i2c_bus_number }}

playbook/roles/olimex-sensor/templates/read_bme280.j2

@@ -6,9 +6,9 @@ from bme280 import bme280_i2c
 from bme280.bme280 import read_all
 
 bme280_i2c.set_default_i2c_address(int("0x77", 0))    # address of sensor 0x77
-bme280_i2c.set_default_bus(int({{ i2c_bus_number }})) # i2c bus number 3 (i2c-3)
+bme280_i2c.set_default_bus(int({{ i2c_bus_number }})) # depends on distro version
 bme280.setup()
 
 data = bme280.read_all()
 
-print("{}\t{}\t{}".format(data.pressure,data.humidity,data.temperature))
+print("{}\t{}\t{}".format(data.pressure, data.humidity, data.temperature))