I want to implement a Java application as a daemon / service that runs on my Raspberry Pi with standard Debian Stretch (Kernel version 4.9).
The java application starts but then throws an exeption because it cannot read an important config file which resides outside the jar. This is by design. I want to keep the config files outside the jar.
I got it running by putting the config files in the jar and reading the files via InputStream. But the requirements are that the config files are not inside the jar. Manually starting the jar via terminal also works. File permssions should be fine as indicated by the working manual startup as root.
My hunch is that the working directory gets messed up during service startup. Another hunch is that navigating the file system via FileInputStream causes issues.
This is my service file:
[Unit]
Description=collector
[Service]
User=root
CHDIR=/opt/servicedir/
#application.properties:
ExecStart=/usr/bin/java -jar /opt/servicedir/javaapp.jar
SuccessExitStatus=143
TimeoutStopSec=10
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
File permssions for everything in /opt/servicedir/: sudo chmod -R 770 /opt/servicedir/
Exception from syslog:
Aug 31 14:38:58 raspberrypi systemd[1]: myservice.service: Main process exited, code=exited, status=1/FAILURE
Aug 31 14:38:58 raspberrypi systemd[1]: myservice.service: Unit entered failed state.
Aug 31 14:38:58 raspberrypi systemd[1]: myservice.service: Failed with result 'exit-code'.
Aug 31 14:39:03 raspberrypi systemd[1]: myservice.service: Service hold-off time over, scheduling restart.
Aug 31 14:39:03 raspberrypi systemd[1]: Stopped service
Aug 31 14:39:03 raspberrypi systemd[1]: Started service
Aug 31 14:39:04 raspberrypi java[7982]: Exception in thread "main" java.lang.ExceptionInInitializerError
Aug 31 14:39:04 raspberrypi java[7982]: #011at foo.bar.Application.<clinit>(Application.java:20)
Aug 31 14:39:04 raspberrypi java[7982]: #011at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
Aug 31 14:39:04 raspberrypi java[7982]: #011at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
Aug 31 14:39:04 raspberrypi java[7982]: #011at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
Aug 31 14:39:04 raspberrypi java[7982]: #011at java.lang.reflect.Method.invoke(Method.java:497)
Aug 31 14:39:04 raspberrypi java[7982]: #011at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
Aug 31 14:39:04 raspberrypi java[7982]: #011at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
Aug 31 14:39:04 raspberrypi java[7982]: #011at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
Aug 31 14:39:04 raspberrypi java[7982]: #011at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)
Aug 31 14:39:04 raspberrypi java[7982]: Caused by: java.lang.RuntimeException: Failed to load credentials.properties.
Aug 31 14:39:04 raspberrypi java[7982]: #011at foo.bar.Config.<clinit>(Config.java:60)
Aug 31 14:39:04 raspberrypi java[7982]: #011... 9 more
Aug 31 14:39:04 raspberrypi java[7982]: Caused by: java.io.FileNotFoundException: ./res/credentials.properties (Datei oder Verzeichnis nicht gefunden)
Aug 31 14:39:04 raspberrypi java[7982]: #011at java.io.FileInputStream.open0(Native Method)
Aug 31 14:39:04 raspberrypi java[7982]: #011at java.io.FileInputStream.open(FileInputStream.java:195)
Aug 31 14:39:04 raspberrypi java[7982]: #011at java.io.FileInputStream.<init>(FileInputStream.java:138)
Aug 31 14:39:04 raspberrypi java[7982]: #011at java.io.FileInputStream.<init>(FileInputStream.java:93)
Aug 31 14:39:04 raspberrypi java[7982]: #011at foo.bar.Application.Config.<clinit>(Config.java:44)
Aug 31 14:39:04 raspberrypi java[7982]: #011... 9 more
Aug 31 14:39:04 raspberrypi systemd[1]: myservice.service: Main process exited, code=exited, status=1/FAILURE
Aug 31 14:39:04 raspberrypi systemd[1]: myservice.service: Unit entered failed state.
Aug 31 14:39:04 raspberrypi systemd[1]: myservice.service: Failed with result 'exit-code'.
Here the code line from java code:
// this does not work :
String credentialsFilePath = "./res/credentials.properties"
try (FileInputStream in = new FileInputStream(credentialsFilePath)) {
// this line works with the config file inside the jar
String credentialsInJar = "credentials.properties"
try (InputStream in = Config.class.getResourceAsStream(credentialsInJar)) {
