Launcher Service Interface
- Kevin Wu
When you run the Desktop Launcher, you may add one or more launcher services that provide connection settings for instances. You may use launcher services as an alternative to manually entering the settings for each instance.
A launcher service is an external web service that returns a list of existing Platform processes to the desktop launcher. The launcher will only know the URL to the service and uses this information to retrieve the list of instances via HTTP GET.
Launcher services are useful in a dynamic environment, e g cloud deployments, where platforms are expected to change IP addresses and ports often. But it can also be useful in a static environments since it reduces the need for manual configuration.
Response Format
In order for the Desktop Launcher to correct parse the response from launcher service, it must adhere to the following format.
mz.<unique identifier>.<attribute>=<value>The unique identifier is used for grouping attributes of a  instance. You may use e g a UUID for this purpose.Â
The following attributes are available:
Attribute | Description |
|---|---|
| The URL Platform Container host, e g |
| An arbitrary name of the instance that will be displayed in the Desktop Launcher. This is attribute is mandatory. |
overrides.pico.rcp.platform.port | When the Desktop connects to the Platform it retrieves the value of the property |
Example - GET request with curl and response from launcher service
$ curl examplehost.com
mz.139808b7-b9ad-4434-9dbd-5233188c6b2c.url=http://10.10.46.1:9000
mz.139808b7-b9ad-4434-9dbd-5233188c6b2c.name=test-environment
mz.a01884d2-cd76-4080-857c-db1d42d8ecdc.url=https://example.com:32768
mz.a01884d2-cd76-4080-857c-db1d42d8ecdc.name=prod-environment
mz.a01884d2-cd76-4080-857c-db1d42d8ecdc.overrides.pico.rcp.platform.port=32770Example Implementation
Below is an example of a launcher service implementation written in Python. The script will return the contents of the file that is specified in the first argument.
#!/usr/bin/env python
import sys
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
class LauncherService(BaseHTTPRequestHandler):
def do_GET(self):
try:
f = open(sys.argv[1], 'r')
self.send_response(200)
self.send_header('Content-type', 'text/plain')
self.end_headers()
self.wfile.write(f.read())
f.close()
return
except IOError:
self.send_error(404, 'file not found')
def run():
server_address = ('0.0.0.0', 80)
httpd = HTTPServer(server_address, LauncherService)
print('http server is running...')
httpd.serve_forever()
if __name__ == '__main__':
run()To run the script:
Install python 2x.
Save the code above in a file named
launcher_service.py.Create a file that contains the instance information. For further information, see Response Format above.
Set executable permissions on the file:
Run the script:
You may now add the service in the Desktop Launcher. For further information, see 1.1.1 Desktop Launcher in the Desktop User's Guide.