Why is my Systemd service not passing parameters from my EnvironmentFile?

Question

I'm new-ish to systemd. I've got a service that's been working fine with the ExecStart command line hard-coded. Now I'm trying to parameterize it, and I found EnvironmentFile written up online. So I modified my service file as follows (some things obfuscated for privacy):

[Service]
Type=simple
EnvironmentFile=/etc/my-service/my-service-systemd.cfg
ExecStart=/usr/local/bin/my-service -port=$PORT -log-level=$LOG_LEVEL -creds=$CREDENTIALS_FILE
ExecStop=/bin/kill -15 $MAINPID

I checked, and the environment file /etc/my-service/my-service-systemd.cfg is definitely there:

CREDENTIALS_FILE=/etc/my-service/my-service.pwd
LOG_LEVEL=2
PORT=443

But when I run the service, it fails, and the logs indicate that all parameters are coming in empty, i.e. the service file is not passing in values from the EnvironmentFile.

What am I doing wrong?

Answer 1

There are rules on the expansion of the $ prefix in ExecStart and so on. There is a difference between $var and ${var}. The former will only be interpolated if it occurs as a word on its own (surrounded by whitespace). The latter does not have this restriction. So use, for example,

-port=${PORT}

The reference for this is under the heading COMMAND LINES in man systemd.service.

Answer 2

It may be related to file permissions. See if this fixes it:

chown root:root /etc/my-service/my-service-systemd.cfg 
chmod 0640 /etc/my-service/my-service-systemd.cfg