Trying to write a custom buildpack along with Java paketo buildpack

[Rvarman0110]

#!/usr/bin/env bash

echo "---> Keycloak Buildpack"
set -euo pipefail

1. GET ARGS

layersdir=$1

2. CREATE THE LAYER DIRECTORY

keycloak_layer="${layersdir}"/keycloak
mkdir -p "${keycloak_layer}"

3. MAKE keycloak AVAILABLE DURING LAUNCH

echo -e '[types]\nlaunch = true' > "${layersdir}/keycloak.toml"

4. INSTALL KEYCLOAK

curl -L https://github.com/keycloak/keycloak/releases/download/24.0.1/keycloak-24.0.1.tar.gz -o "${layersdir}/keycloak-24.0.1.tar.gz"
tar -xzf "${layersdir}/keycloak-24.0.1.tar.gz" -C "${keycloak_layer}"

6. Set environment variables

export KC_HEALTH_ENABLED=true
export KC_METRICS_ENABLED=true
export KC_DB=postgres

7. Copy generated JAR files from previous Buildpack to Keycloak folders

find ./addons/target -regex './addons/target/keycloak-addons-[0-9]+.[0-9]+.[0-9]+-[0-9]+T[0-9]+-[0-9a-f]+.jar' | grep -v 'sources' | xargs -I{} cp {} "${keycloak_layer}/keycloak-24.0.1/providers/keycloak-addons.jar"
find ./scripts/target -regex './scripts/target/keycloak-scripts-[0-9]+.[0-9]+.[0-9]+-[0-9]+T[0-9]+-[0-9a-f]+.jar' | grep -v 'sources' | xargs -I{} cp {} "${keycloak_layer}/keycloak-24.0.1/providers/keycloak-scripts.jar"
find ./idp-mapper/target -regex './idp-mapper/target/idp-mapper-[0-9]+.[0-9]+.[0-9]+-[0-9]+T[0-9]+-[0-9a-f]+.jar' | grep -v 'sources' | xargs -I{} cp {} "${keycloak_layer}/keycloak-24.0.1/providers/idp-mapper.jar"
cp ./themes/open-blue /opt/keycloak/themes/open-blue-theme
cp ./target/keycloak-server-copy/* "${keycloak_layer}/keycloak-24.0.1/providers/

8. Build scripts with specified variables

cd "${keycloak_layer}"
./keycloak-24.0.1/bin/kc.sh build --http-relative-path /auth --features=scripts

exit 0

I followed https://buildpacks.io/docs/for-buildpack-authors/tutorials/basic-buildpack/07_make-buildpack-configurable/ this documentaion to write this buildpack

Then in builder.toml file

[[order]]

[[order.group]]
id = "paketo-buildpacks/java"
version = "10.5.0"

[[order.group]]
id = "custom-buildpack/keycloak"
version = "0.0.4"

I have mentioned like this now it is participating everything works fine but 

the 7th step where  I am trying to copy the jars and themes into keycloak folder so that I can build the keycloak with kc.sh build 

but i am getting an error as no such file or directory but it should be there and it is there why I am facing this issue 


**logs:
[builder]       [INFO] Reactor Summary for keycloak :

[builder] [INFO]
[builder] [INFO] keycloak ..................................... SUCCESS [02:16 min]
[builder] [INFO] Keycloak Addons .................................... SUCCESS [01:36 min]
[builder] [INFO] Keycloak Scripts ................................... SUCCESS [ 0.162 s]
[builder] [INFO] Keycloak-Okta IdP Group Mapper ..................... SUCCESS [ 0.694 s]
[builder] [INFO] ------------------------------------------------------------------------
[builder] [INFO] BUILD SUCCESS
[builder] [INFO] ------------------------------------------------------------------------
[builder] [INFO] Total time: 04:35 min
[builder] [INFO] Finished at: 2024-03-26T13:10:01Z
[builder] [INFO] ------------------------------------------------------------------------
[builder]
[builder] Removing source code
[builder] Restoring multiple artifacts

[builder] --->Keycloak Buildpack

[builder] % Total % Received % Xferd Average Speed Time Time Time Current
[builder] Dload Upload Total Spent Left Speed
[builder] 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
[builder] 100 168M 100 168M 0 0 6904k 0 0:00:24 0:00:24 --:--:-- 8540k
[builder] cp: cannot stat './themes/open-blue': No such file or directory
[builder] ERROR: failed to build: exit status 1
ERROR: failed to build: executing lifecycle. This may be the result of using an untrusted builder: failed with status code: 51**

[dmikusa]

[builder] Removing source code
[builder] Restoring multiple artifacts

It could be this part. The Maven buildpack, when it runs, will copy the output and save that to a layer. It then deletes everything because you don't want source code in the final image and restored the saved files from the layer to /workspace (i.e. where your app source used to be).

The net result is that the image now contains your built files, not the source files.

If you're trying to access something from the source files after Maven runs, it won't exist unless it's been included in the built files and if it was in the built files then it'll be in a different location (because target/ doesn't exist anymore). The new location is such that /workspace is the root and all of the files it saves are put into that directory.

In your case, it's saving multiple JAR files so you'll have a collection of JAR files in /workspace. You might just add in a ls -l /workspace to see what it's persisted across the build.

If you want it to not delete stuff, there's an include/exclude setting you can use. See BP_INCLUDE_FILES/BP_EXCLUDE_FILES here -> https://github.com/paketo-buildpacks/maven?tab=readme-ov-file#configuration for details.

The other buildpacks in the Java buildpack do expect things to be in certain locations to work properly. If you're depending on executable-jar or apache-tomcat or another buildpack to make your app actually run, then you need to be careful to keep things where they are expected. If your buildpack is going to handle all of that, then you can do whatever you want. You could tell Maven to keep everything and then have your buildpack be in charge of what is removed from the final image. Just understand that whatever's left in /workspace when all the buildpacks are done goes into the final image.

Hope that helps!

[Rvarman0110]

Thanks @dmikusa , yep that helped me I included the files using BP_INCLUDE_FILES and used BP_MAVEN_BUILT_ARTIFACT to mention every jars which eventually ended up in final image