diagnostics: Add shortcut to re-run setup for app

- When running diagnostics for an app, if there are any failures or warnings,
  then show a button to re-run setup.

- When showing all diagnostics results, if there are any failures or warnings
  for an app, then show a button to re-run setup for that app.

Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
[sunil: Use Result class instead of strings for comparison]
[sunil: Use flex box's justify-content-between to improve button styling]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/diagnostics/__init__.py

@@ -126,6 +126,7 @@ def _run_on_all_enabled_modules():
         app_results = {
             'diagnosis': None,
             'exception': None,
+            'show_rerun_setup': False,
         }
 
         try:
@@ -135,6 +136,11 @@ def _run_on_all_enabled_modules():
                              exception)
             app_results['exception'] = str(exception)
 
+        for check in app_results['diagnosis']:
+            if check.result in [Result.FAILED, Result.WARNING]:
+                app_results['show_rerun_setup'] = True
+                break
+
         with results_lock:
             current_results['results'][app_id].update(app_results)
             current_results['progress_percentage'] = \

plinth/modules/diagnostics/templates/diagnostics_app.html

@@ -9,7 +9,18 @@
 
   <h2>{% trans "Diagnostic Results" %}</h2>
 
-  <h3>{% blocktrans %}App: {{ app_name }}{% endblocktrans %}</h3>
+  <div class="row align-items-center justify-content-between">
+    <h3>{% blocktrans %}App: {{ app_name }}{% endblocktrans %}</h3>
+
+    {% if show_rerun_setup %}
+      <form class="form form-diagnostics-rerun-setup-button" method="post"
+            action="{% url 'rerun-setup' app_id=app_id %}">
+        {% csrf_token %}
+        <input type="submit" class="btn btn-default"
+               name="rerun-setup" value="{% trans "Re-run setup" %}"/>
+      </form>
+    {% endif %}
+  </div>
 
   {% if results %}
     {% include "diagnostics_results.html" with results=results %}

plinth/modules/diagnostics/templates/diagnostics_full.html

@@ -33,11 +33,22 @@
   {% if results %}
     <h3>{% trans "Results" %}</h3>
     {% for app_id, app_data in results.results.items %}
-      <h4>
-        {% blocktrans with app_name=app_data.name %}
-          App: {{app_name}}
-        {% endblocktrans %}
-      </h4>
+      <div class="row align-items-center justify-content-between">
+        <h4>
+          {% blocktrans with app_name=app_data.name %}
+            App: {{app_name}}
+          {% endblocktrans %}
+        </h4>
+
+        {% if app_data.show_rerun_setup %}
+          <form class="form form-diagnostics-rerun-setup-button" method="post"
+                action="{% url 'rerun-setup' app_id=app_id %}">
+            {% csrf_token %}
+            <input type="submit" class="btn btn-default"
+                   name="rerun-setup" value="{% trans "Re-run setup" %}"/>
+          </form>
+        {% endif %}
+      </div>
 
       {% if app_data.diagnosis %}
         {% include "diagnostics_results.html" with results=app_data.diagnosis %}

plinth/modules/diagnostics/views.py

@@ -17,6 +17,8 @@ from plinth.app import App
 from plinth.modules import diagnostics
 from plinth.views import AppView
 
+from .check import Result
+
 logger = logging.getLogger(__name__)
 
 
@@ -87,10 +89,18 @@ def diagnose_app(request, app_id):
                          exception)
         diagnosis_exception = str(exception)
 
+    show_rerun_setup = False
+    for check in diagnosis:
+        if check.result in [Result.FAILED, Result.WARNING]:
+            show_rerun_setup = True
+            break
+
     return TemplateResponse(
         request, 'diagnostics_app.html', {
             'title': _('Diagnostic Test'),
+            'app_id': app_id,
             'app_name': app_name,
             'results': diagnosis,
             'exception': diagnosis_exception,
+            'show_rerun_setup': show_rerun_setup,
         })