MyApp: a WPS template for CP4CDS

Warning

This template is outdated. Please use the Cookiecutter template

MyApp is a minimal WPS to be used as a template to setup Web Processing Services (WPS) in the CP4CDS Copernicus project.

Currently it is using the PyWPS WPS implementation.

Installation

The installation is done with Buildout. It is using the Python distribution system Anaconda to maintain software dependencies.

If Anaconda is not available then a minimal Anaconda will be installed during the installation process in your home directory ~/anaconda.

The installation process setups a conda environment named myapp. All additional packages are going into this conda environment. The location is ~/.conda/envs/myapp.

Now, check out the code from the GitHub repo as myapp and start the installation:

$ git clone https://github.com/cp4cds/cp4cds-wps-template.git myapp
$ cd myapp
$ make clean install

After successful installation you need to start the services. All installed files (config etc ...) are by default in your home directory ~/birdhouse. Now, start the services:

$ make start  # starts supervisor services
$ make status # shows supervisor status

The deployed WPS service is available on http://localhost:5000/wps?service=WPS&version=1.0.0&request=GetCapabilities.

Check the log files for errors:

$ cd ~/birdhouse
$ tail -f  var/log/pywps/myapp.log
$ tail -f  var/log/supervisor/myapp.log

For other install options run make help and read the documention of the Makefile.

Configuration

If you want to run on a different hostname or port then change the default values in custom.cfg:

$ cd wps
$ vim custom.cfg
$ cat custom.cfg
[settings]
hostname = localhost
http-port = 5000

After any change to your custom.cfg you need to run make update (offline mode) or make install again and restart the supervisor service:

$ make install
$ make restart
$ make status

Running WPS service in test environment

For development purposes you can run the WPS service without nginx and supervisor. Use the following instructions:

# get the source code
$ git clone https://github.com/cp4cds/cp4cds-wps-template.git myapp
$ cd myapp

# create conda environment
$ conda env create -f environment.yml

# activate conda environment
$ source activate myapp

# install myapp code into conda environment
$ python setup.py develop

# start the WPS service
$ myapp

# open your browser on the default service url
$ firefox http://localhost:5000/wps

# ... and service capabilities url
$ firefox http://localhost:5000/wps?service=WPS&request=GetCapabilities

Using Docker

Get docker images using docker-compose:

$ docker-compose pull

Start the demo with docker-compose:

$ docker-compose up -d  # runs with -d in the background
$ docker-compose logs -f  # check the logs if running in background

By default the WPS service should be available on port 5000:

$ firefox "http://localhost:5000/wps?service=wps&request=GetCapabilities"

Alternatively you can change the port by using environment variables, for example:

$ HTTP_PORT=8097 docker-compose up -d # wps service will be available on port 8097

Run docker exec to watch logs:

$ docker ps     # find container name
myapp_myapp_1
$ docker exec myapp_myapp_1 tail -f /opt/birdhouse/var/log/supervisor/myapp.log
$ docker exec myapp_myapp_1 tail -f /opt/birdhouse/var/log/pywps/myapp.log

Use docker-compose to stop the containers:

$ docker-compose down

Example run with Birdy

To have some more convenience you can use the birdy WPS commandline client.

Install it via the conda package manager:

$ conda install -c birdhouse -c conda-forge birdhouse-birdy

Configure the WPS service:

$ export WPS_SERVICE=http://localhost:5000/wps

Now, run the birdy on the say_hello process:

$ birdy -h
$ birdy say_hello -h
$ birdy say_hello --name Birdy
[ProcessAccepted 0/100] PyWPS Process say_hello accepted
[ProcessSucceeded 0/100] PyWPS Process Process Say Hello finished
Output:
output=Hello Birdy

Generate a simple plot for a netCDF file from a public thredds server:

$ birdy simple_plot -h
$ birdy simple_plot \
  --variable air \
  --dataset https://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/ncep.reanalysis.derived/surface/air.mon.ltm.nc

[ProcessAccepted 0/100] PyWPS Process simple_plot accepted [ProcessSucceeded 0/100] PyWPS Process Simple Plot finished Output: output=http://localhost:8090/wpsoutputs/myapp/17031194-9d2d-11e7-9809-68f72837e1b4/plot.png (image/png)