Saturday, September 21, 2024

Hello World as a Service


Writing a service is the same as writing a command-line program in Golf. Both take the same input and produce the same output, so you can test with either one to begin with.

For that reason, create first Hello World as a command-line program.

The only thing to do afterwards is to start up Hello World as application server:
mgrg hello

Now there's a number of resident processes running, expecting clients requests. You can see those processes:
ps -ef|grep hello

The result:
bear       25772    2311  0 13:04 ?        00:00:00 mgrg hello
bear       25773   25772  0 13:04 ?        00:00:00 /var/lib/gg/bld/hello/hello.srvc
bear       25774   25772  0 13:04 ?        00:00:00 /var/lib/gg/bld/hello/hello.srvc
bear       25775   25772  0 13:04 ?        00:00:00 /var/lib/gg/bld/hello/hello.srvc
bear       25776   25772  0 13:04 ?        00:00:00 /var/lib/gg/bld/hello/hello.srvc
bear       25777   25772  0 13:04 ?        00:00:00 /var/lib/gg/bld/hello/hello.srvc

"mgrg hello" runs the Golf process manager for application "hello". A number of ".../hello.srvc" processes are server processes that will handle service request sent to application "hello".

Now, to test your service, you can send a request to the server from command line (by using "--service" option):
gg -r --req="/hello-world/name=Mike" --exec --silent-header --service

The above will make a request to one of the processes above, which will then reply:
This is Hello World from Mike