Makefile multiline dash command run executable in a detached process - bash

Question

I have the following target in my makefile: (I'd like to run python http server in a detached process and when bash script is done kill the server)
TEST_PORT = 17777
test::
$(ENV_VARS) \
python -m SimpleHTTPServer $(TEST_PORT); \
PID=$$(lsof -t -i #localhost:$(TEST_PORT) -sTCP:listen); \
echo $(PID); \
if [ -n "$$PID" ]; \
then \
python test.py; \
fi; \
function finish { \
if [ -n "$$PID" ]; \
then \
kill -9 $$PID; \
fi \
} \
trap finish EXIT;
However when I put a & after the line python ... I get an error
/bin/dash: Syntax error: ";" unexpected
How can this be done in a proper way?
EDIT
I have changed my makefile to do the following:
test::
python -m SimpleHTTPServer $(TEST_PORT) &
PID=$$(lsof -t -i #localhost:$(TEST_PORT) -sTCP:listen); \
if [ -n "$$PID" ]; \
then \
$(ENV_VARS) python test.py; \
fi \
function finish { \
if [ -n "$$PID" ]; \
then \
kill -9 $$PID; \
fi \
} \
echo $$PID; \
trap finish EXIT;
However I am getting an error: (without the line number)
/bin/dash: Syntax error: word unexpected

Answer 1

The important thing to remember here is that your line breaks don't actually exist when the shell sees the command.
So your first command becomes:
$(ENV_VARS) python -m SimpleHTTPServer $(TEST_PORT); PID=$$(lsof -t -i #localhost:$(TEST_PORT) -sTCP:listen); echo $(PID); if [ -n "$$PID" ]; then python test.py; fi; function finish { if [ -n "$$PID" ]; then kill -9 $$PID; fi } trap finish EXIT;
And your second command becomes:
PID=$$(lsof -t -i #localhost:$(TEST_PORT) -sTCP:listen); if [ -n "$$PID" ]; then $(ENV_VARS) python test.py; fi function finish { if [ -n "$$PID" ]; then kill -9 $$PID; fi } echo $$PID; trap finish EXIT;
Now those are both very hard to read so I don't expect you to spot the problem but the problem is that you are missing statement terminators in a few places.
Specifically:
Braces ({}) are word elements and so need spaces around them (and a terminator before, and after, the closing brace). You are missing those terminators here fi } trap and here fi } echo.
fi is also not a statement terminator and so it needs one between it and the next statement. You are missing one here test.py; fi function (as well as the ones in the braces from the first point).