Environment variables for a specific command

[l0rd]

Should it be possible to set environment variables that apply for a specific command? The current way to handle this would be to set the environment variables inline with the command but this can be cumbersome and reduce readability.

Sample of current devfile snippet to show example of usage/format:

- exec:
     commandLine: "MAVEN_CONFIG=~/mvn/config JAVA_OPTS="-XX:MaxRAMPercentage=50.0 -XX:+UseParallelGC -XX:MinHeapFreeRatio=10
               -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90
               -Dsun.zip.disableMemoryMapping=true -Xms20m -Djava.security.egd=file:/dev/./urandom
               -Duser.home=/home/user" ./buildSchema.sh"
     component: build-tools
     alias: buildSchema

Example with proposed changes:

commands:
 - exec:
     commandLine: "./buildSchema.sh"
     env:
     - name: MAVEN_CONFIG
       value: "~/mvn/config"
     - name: JAVA_OPTS
       value: "-XX:MaxRAMPercentage=50.0 -XX:+UseParallelGC -XX:MinHeapFreeRatio=10
               -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90
               -Dsun.zip.disableMemoryMapping=true -Xms20m -Djava.security.egd=file:/dev/./urandom
               -Duser.home=/home/user"
     component: build-tools
     alias: buildSchema

[l0rd]

cc @johnmcollier @elsony

[davidfestal]

That would be very easy to do, model-wise, and quite consistent with the way environment is mentioned in other parts of the devfile (in container components for example).

[l0rd]

Reviewed and approved

[maysunfaisal]

I am wondering what is the benefit of doing this way as opposed to having the ENV defined for the component container?

Also what happens if multiple commands are referencing the same component and require the same ENV? Will I need to mention it twice in the respective command? That seems redundant IMO..

[johnmcollier]

@maysunfaisal This allows you to easily set variables for just one command, without needing to change the default value for the entire container, and to allow separate commands to have separate values for the same variable.

The environment variable value will only be set in the context of the command, and shouldn't conflict with other commands setting the same variable.

The example given in issue description is a good one, setting different values of JAVA_OPTS for each separate command as needed.

[maysunfaisal]

@johnmcollier will 2.0 spec support defining ENV on the component level as well or just on the command level?

[johnmcollier]

@maysunfaisal Both

[davidfestal]

Implemented