Passing external configuration file?

[DarthJonathan]

Hi @vmencik !

I have a question, how do we pass an external configuration file to the binary? I passed -Dconfig.file flag to the binary does not seem to work

./app -Dconfig.file=/opt/conf/application.conf

even when building I pass the config file.. for reference this is my build config

"-Dconfig.resource=/opt/conf/application.conf",
"--static",
"--verbose",
"--no-fallback",
"--install-exit-handlers",
"--enable-http",
"--enable-https",
"--enable-url-protocols=https,http",
"--allow-incomplete-classpath",
"--initialize-at-run-time=scala.util.Random$" +
",io.grpc.netty.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine" +
",io.netty.util.internal.logging.Log4JLogger" +
",io.grpc.netty.shaded.io.netty.internal.tcnative.CertificateCompressionAlgo",
"--initialize-at-build-time=io.netty.handler.ssl.BouncyCastleAlpnSslUtils" +
",ch.qos.logback",
"--report-unsupported-elements-at-runtime",
"-H:IncludeResources=.*\.properties",
"-H:+StaticExecutableWithDynamicLibC",
"-H:+RemoveSaturatedTypeFlows",
"-H:+ReportExceptionStackTraces",
"-H:-ThrowUnsafeOffsetErrors",
"-H:+PrintClassInitialization",
"-H:ReflectionConfigurationFiles=/build/graal/reflect-config.json",
"-H:Name=app",

thanks!

[vmencik]

Hi. It's been a while since I had my hands on this. In my notes I could only find one issue with the Lightbend Config library which was that it "caches" the environment in a static field, so I had to use this option to re-initialize it at runtime:

--rerun-class-initialization-at-runtime=com.typesafe.config.impl.ConfigImpl$EnvVariablesHolder,com.typesafe.config.impl.ConfigImpl$SystemPropertiesHolder

But this is only for the parts of the configuration that references environment variables or Java system properties.
I only used the application.conf files embedded as a classpath resource. I don't see why -Dconfig.file shouldn't work.