A build routine is simply a function that receives a build request and returns a build response, as long as those conditions are met, you can do whatever you please from within that function. Here is a bare-bones example build routine.
import random
import subprocess
from monarch.builder import *
from subprocess import STDOUT, check_output
import os
import base64
def routine(req: BuildRequest) -> BuildResponse:
agent_id = req.params.get("id") # definitely exists - was passed by monarch itself
host = req.params.get("host")
port = req.params.get("port")
# config.json will be embedded into the Go binary at compile time (go embed)
with open("config/config.json", "w") as f:
j = {
"id": agent_id,
"host": host,
"port": port,
}
j_string = json.dumps(j)
f.write(j_string)
out = random.randbytes(10).decode('utf-8')
cmd = "go build -o %s ." % out
data = b""
my_env = os.environ.copy()
my_env["GOOS"] = req.params.get("os")
my_env["GOARCH"] = req.params.get("arch")
try:
error = check_output(cmd.split(), stderr=STDOUT, env=my_env)
except subprocess.CalledProcessError as e:
# return build error
error = e.output.decode('utf-8')
# path doesn't exist if build failed
if not os.path.exists(out):
status = 1
else:
status = 0
error = ""
with open(out, "rb") as f:
data = f.read()
res = BuildResponse(status, error, base64.b64encode(data).decode('utf-8'))
return res
It uses the host, port and ID parameters provided by the Monarch server to build the binary with a configuration file. It also ensures that any errors that may occur are caught and dealt with.
The returned build must be represented as base64 encoded data, as this is the chosen representation of raw bytes for Monarch. A successful build response from the Python build service to the Monarch build client would look like so: