02e3916bf5
[needs-docs]
In vector layer properties (only usefull for postgres datasources)
**in the rendering tab**
A "Refresh layer on notification" checkbox has been added to refresh layer
on provider notification.
For a postgres datasource, if a `NOTIFY qgis;` command is issued by one of the database clients,
a refresh of the layer will occur.
If the "Only if message is" checkbox is checked, the notification will trigger the refresh only
if the message contend is the one specified, e.g. if the user enters
"refresh" in the box right next to the "Only if message is" checkbox,
then a `NOTIFY qgis, 'refresh';` command in the datatabase will trigger
a layer refresh, but `NOTIFY qgis;` or `NOTIFY qgis, 'something else';`
won't.
**in the actions tab**
A column "On notification" has been added, the action editor widget
a has text field "Execute if notification message matches" to
specify a filter for notification from the provider. The filter is a
Perl-type regex.
Note that, as opposed to the "layer refresh" that
Exemple:
- QGIS side "Execute if notification message matches" `^trigger my action`
- Postgres side: `NOTIFY qgis, 'trigger my action'` will trigger the action
- Postgres side: `NOTIFY qgis, 'trigger my action some additional data'` will trigger the action
- Postgres side: `NOTIFY qgis, 'do not trigger my action some additional data'` will NOT trigger the action
Please note that if the `^`, which means "starts with", in `^trigger my action` had been ommited,
the last notification would have triggered the action because the
notification message contains the `trigger my action`
A new qgis variable `notification_message` is available for use in
actions, it holds the contend of the notification message. To continue
with the previous exemple, if the action is of python type with the code:
```python
print('[% @notification_message %]')
```
The three notifictions above will result in two printed lines
```
trigger my action
trigger my action some additional data
```
User Warning:
For postgres providers, if the "Refresh layer on notification" is checked, or if one layer action has
"On notification" specified, a new connection to the database is made to
listen to postgres notifications. This olds even if transaction groups
are enabled at the project level.
Note that once the notification mechanism is started in a QGIS
session, it will not stop, even if there is no more need for it (Refresh
layer on notification" unchecked and no "On notification" in any
action). Consequently the connection listening to notification will
remain open.
IMPLEMENTATION DETAILS:
A notify signal has been added to the abstract QgsVectorDataProvider
along with a setListening function that enables/disble the notification
mechanism.
For the moment only the postgres provider implements the notification.
QgsAction has a notificationMessage member function that holds the regex
to match to trigger action
QgsActionManager becomes a QObject and is doing the filtering and execute actions on
notifications.
The notification notion extends beyond SRGBD servers (postgres and oracle at
least have the notify) and the "watch file" in the delimitedtext
provider could also benefit from this interface.
For the postgres provider a thread is created with a second connection
to the database. This thread is responsible for listening postgres
notifications.
It would be nice to avoid the creation of one listening chanel per
provider in the case transaction groups are enabled.
Please note that when listening starts (a thread and connection is
created in the postgres provider) it cannot be stopped by removing the
connected actions or unchecking the refresh check box. Indeed, since we
don't know who needs the signals, we dont't want to stop the service.
The service will not restart in the next qgis session though.
If this behavior is not deemed appropriate, we could use
```
int QObject::receivers ( const char * signal ) const
```
and have QgsDataProvider::setListening return a bool to tell the caller
if the signal has actually been closed.
QGIS unit tests
Build tests
Make sure that you have enabled building of tests in CMake.
cmake -DENABLE_TESTS=ON ..
Run tests
You can run all tests using make check.
Note you will need xvfb-run for that (sudo apt-get install xfvb).
Individual tests can be run using ctest.
For example if the output of make check ends like this:
The following tests FAILED:
77 - PyQgsLocalServer (Failed)
You could re-run the failing test with:
ctest -V -R PyQgsLocalServer
The parameter -V enables verbose mode and -R takes a regular expression as
parameter and will only run matching tests.
For python tests, you can run a specific test inside a unit file with something like this:
QGIS_PREFIX_PATH=output PYTHONPATH=output/python:$PYTHONPATH \
python ${srcdir}/tests/src/python/test_qgsvectorfilewriter.py
TestQgsVectorLayer.testOverwriteLayer
Advanced configuration
Postgres
Make sure that you have enabled building of postgres test in CMake.
cmake -DENABLE_TESTS=ON -DENABLE_PGTEST=ON ..
To test the postgres provider you will need to have a database available to which the postgres provider can connect. The server will need to have PostGIS support enabled.
By default the test uses one of the following connection string:
dbname=qgis_test
service=qgis_test
If these do not match your setup you can set the environment variable
QGIS_PGTEST_DB to the desired connection string. Note that you can
rely on standard libpq environment variables to tweak host, port user
and password (PGHOST, PGPORT, PGUSER, PGPASSWORD).
Please note that the test database needs to be initialized using the sql-scripts:
tests/testdata/provider/testdata_pg*.sql
They take care of activating PostGIS for the test database and create some tables containing test data.
For convenience, a shell script is provided to create the database and initialize it as needed:
tests/testdata/provider/testdata_pg.sh
Write tests
Instructions about writing tests for the processing framework can be found in a separate README file:
${TOP_SRCDIR}/python/plugins/processing/tests/README.md
Information about labeling tests design and organization:
${TOP_SRCDIR}/tests/testdata/labeling/README.rst
WCS testing information can be found in:
${TOP_SRCDIR}/tests/testdata/raster/README.WCS
About benchmark tests you can read:
${TOP_SRCDIR}/tests/bench/README
Run python tests in GDB
First find out the required environment variables by running the test outside the debugger.
ctest -V -R ProcessingQgisAlgorithmsTest
Which prints for somewhere in the initialization code something like:
export LD_LIBRARY_PATH=NOTFOUND:/home/m-kuhn/dev/cpp/qgis/build-qt5/output/lib:
export PYTHONPATH=/home/m-kuhn/dev/cpp/qgis/build-qt5/output/python/:/home/m-kuhn/dev/cpp/qgis/build-qt5/output/python/plugins:/home/m-kuhn/dev/cpp/qgis/QGIS/tests/src/python:
First, run these two commands in the terminal.
On the following line it says something like:
-- Running /usr/bin/python3 /home/m-kuhn/dev/cpp/qgis/QGIS/python/plugins/processing/tests/QgisAlgorithmsTest.py
Which you can run in gdb with:
gdb -ex r --args /usr/bin/python3 /home/m-kuhn/dev/cpp/qgis/QGIS/python/plugins/processing/tests/QgisAlgorithmsTest.py
Now you can start using the usual gdb (bt etc.) interface or - if you have
installed the appropriate debug tools (adjust for python3!)
even allows doing python introspection (py-bt).