BP_NATIVE_IMAGE_BUILD_ARGUMENTS replaces arguments added by Datadog BP

[tjuchniewicz]

We use BP_NATIVE_IMAGE=true and BP_DATADOG_ENABLED=true. Both add arguments to native-image. Unfortunately native-image BP removes argument added by Datadog BP.

Expected Behavior

native-image BP appends arguments

Current Behavior

native-image BP replaces arguments

Steps to Reproduce

1. BP_NATIVE_IMAGE_BUILD_ARGUMENTS=-O0 -J-Xmx7g

Paketo Buildpack for Datadog 4.6.0
[INFO]     [creator]       https://github.com/paketo-buildpacks/datadog
[INFO]     [creator]       Build Configuration:
[INFO]     [creator]         $BP_DATADOG_ENABLED    true   whether to contribute the Datadog trace agent
[INFO]     [creator]       Launch Configuration:
[INFO]     [creator]         $BPL_DATADOG_DISABLED  false  whether to disable the Datadog trace agent (non native-image Java applications only!)
[INFO]     [creator]       Datadog Java Agent 1.25.1: Contributing to layer
[INFO]     [creator]         Downloading from https://repo1.maven.org/maven2/com/datadoghq/dd-java-agent/1.25.1/dd-java-agent-1.25.1.jar
[INFO]     [creator]         Verifying checksum
[INFO]     [creator]         Copying to /layers/paketo-buildpacks_datadog/datadog-agent-java
[INFO]     [creator]         Writing env.build/BP_NATIVE_IMAGE_BUILD_ARGUMENTS.append
[INFO]     [creator]         Writing env.build/BP_NATIVE_IMAGE_BUILD_ARGUMENTS.delim
[INFO]     [creator]         Writing env.launch/BPI_DATADOG_AGENT_PATH.default
[INFO]     [creator]     
[INFO]     [creator]     Paketo Buildpack for Native Image 5.12.7
[INFO]     [creator]       https://github.com/paketo-buildpacks/native-image
[INFO]     [creator]       Build Configuration:
[INFO]     [creator]         $BP_BINARY_COMPRESSION_METHOD                        Compression mechanism used to reduce binary size. Options: `none` (default), `upx` or `gzexe`
[INFO]     [creator]         $BP_NATIVE_IMAGE                       true          enable native image build
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILD_ARGUMENTS       -O0 -J-Xmx7g  arguments to pass to the native-image command
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILD_ARGUMENTS_FILE                a file with arguments to pass to the native-image command
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILT_ARTIFACT                      the built application artifact explicitly, required if building from a JAR
[INFO]     [creator]       Native Image: Contributing to layer
[INFO]     [creator]         Executing native-image --no-fallback -H:+StaticExecutableWithDynamicLibC -O0 -J-Xmx7g -H:Name=/layers/paketo-buildpacks_native-image/native-image/com.mercedesbenz.blueprint.Application -cp ...    

In last line Datadog agent configuration is missing.

2. BP_NATIVE_IMAGE_BUILD_ARGUMENTS not set

Paketo Buildpack for Datadog 4.6.0
[INFO]     [creator]       https://github.com/paketo-buildpacks/datadog
[INFO]     [creator]       Build Configuration:
[INFO]     [creator]         $BP_DATADOG_ENABLED    true   whether to contribute the Datadog trace agent
[INFO]     [creator]       Launch Configuration:
[INFO]     [creator]         $BPL_DATADOG_DISABLED  false  whether to disable the Datadog trace agent (non native-image Java applications only!)
[INFO]     [creator]       Datadog Java Agent 1.25.1: Contributing to layer
[INFO]     [creator]         Downloading from https://repo1.maven.org/maven2/com/datadoghq/dd-java-agent/1.25.1/dd-java-agent-1.25.1.jar
[INFO]     [creator]         Verifying checksum
[INFO]     [creator]         Copying to /layers/paketo-buildpacks_datadog/datadog-agent-java
[INFO]     [creator]         Writing env.build/BP_NATIVE_IMAGE_BUILD_ARGUMENTS.append
[INFO]     [creator]         Writing env.build/BP_NATIVE_IMAGE_BUILD_ARGUMENTS.delim
[INFO]     [creator]         Writing env.launch/BPI_DATADOG_AGENT_PATH.default
[INFO]     [creator]     
[INFO]     [creator]     Paketo Buildpack for Native Image 5.12.7
[INFO]     [creator]       https://github.com/paketo-buildpacks/native-image
[INFO]     [creator]       Build Configuration:
[INFO]     [creator]         $BP_BINARY_COMPRESSION_METHOD                                                                                                      Compression mechanism used to reduce binary size. Options: `none` (default), `upx` or `gzexe`
[INFO]     [creator]         $BP_NATIVE_IMAGE                       true                                                                                        enable native image build
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILD_ARGUMENTS       -J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-1.25.1.jar  arguments to pass to the native-image command
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILD_ARGUMENTS_FILE                                                                                              a file with arguments to pass to the native-image command
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILT_ARTIFACT                                                                                                    the built application artifact explicitly, required if building from a JAR
[INFO]     [creator]       Native Image: Contributing to layer
[INFO]     [creator]         Executing native-image --no-fallback -H:+StaticExecutableWithDynamicLibC -J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-1.25.1.jar -H:Name=/layers/paketo-buildpacks_native-image/native-image/com.mercedesbenz.blueprint.Application -cp ...

In last line Datadog argument is included (-J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-1.25.1.jar ).
Please see that native BP recognizes arguments added by Datadog:

[INFO]     [creator]     Paketo Buildpack for Native Image 5.12.7
...
[INFO]     [creator]         $BP_NATIVE_IMAGE_BUILD_ARGUMENTS       -J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-1.25.1.jar  arguments to pass to the native-image command
...

Workaround

Configure Datadog argument manually:

 <BP_NATIVE_IMAGE_BUILD_ARGUMENTS>-O0 -J-Xmx7g -J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-1.25.1.jar</BP_NATIVE_IMAGE_BUILD_ARGUMENTS>

unfortunately this workaround will fail after Datadog BP upgrades agent version

Motivations

We want to use Native, Datadog and custom arguments in the same time due to need to change default native-build memory settings, disable optimizations etc.

[dmikusa]

The way that native-image buildpack handles arguments for native image is different than the way we handle arguments in other buildpacks. Usually, with other buildpacks, the arguments you set just override the buildpack. We don't do that with native-image buildpack because it's complicated to get all the required native-image arguments right, some of which need to be set just so because of the way things work inside buildpacks.

To attempt to allow folks to also pass in arguments, we do some processing of the arguments, restricting/removing certain arguments. This is in an effort to prevent users from accidentally passing in an argument and breaking the build.

It is entirely possible that these extra precautions are preventing something legitimate from being passed in as an argument. I'd have to dig through that logic and see what I can find out.

The other possibility here is that the layer that's setting this environment variable is not a build layer. If it's not a build layer, you can still set build env variables, they just won't appear because the layer is not around when subsequent buildpacks run. A quick glance at the datadog bp code, and it looks like it should be a build layer. It looks like build is true when native image is true. Just mentioning this to be thorough.