Finalize failed with exception error for offline buildpacks

[hp685]

For offline buildpacks JavaBuildpack::Component::BaseComponent#download throws this error
[Buildpack] ERROR Finalize failed with exception #<RuntimeError: Unable to find cached file for http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/controller-info.xml>

This impacts a feature to download configuration files for appd agents

   Downloaded java-offline-bp
   Cell 8c6e8f68-6d7e-46d7-a8b1-75c891704479 creating container for instance b9d798e3-695b-443e-9973-b04bc54f7822
   Cell 8c6e8f68-6d7e-46d7-a8b1-75c891704479 successfully created container for instance b9d798e3-695b-443e-9973-b04bc54f7822
   Downloading app package...
   Downloading build artifacts cache...
   Downloaded build artifacts cache (131B)
   Downloaded app package (40.6M)
   -----> Java Buildpack 712fc0d5 (offline) | https://github.com/hp685/java-buildpack.git#712fc0d5
   -----> Downloading Jvmkill Agent 1.16.0_RELEASE from https://java-buildpack.cloudfoundry.org/jvmkill/bionic/x86_64/jvmkill-1.16.0-RELEASE.so (found in cache)
   -----> Downloading Open Jdk JRE 1.8.0_252 from https://java-buildpack.cloudfoundry.org/openjdk/bionic/x86_64/bellsoft-jre8u252%2B9-linux-amd64.tar.gz (found in cache)
          Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (3.4s)
          JVM DNS caching disabled in lieu of BOSH DNS caching
   -----> Downloading Open JDK Like Memory Calculator 3.13.0_RELEASE from https://java-buildpack.cloudfoundry.org/memory-calculator/bionic/x86_64/memory-calculator-3.13.0-RELEASE.tar.gz (found in cache)
          Loaded Classes: 17948, Threads: 250
   -----> Downloading AppDynamics Agent 4.5.19_29609 from https://packages.appdynamics.com/java/4.5.19.29609/AppServerAgent-4.5.19.29609.zip (found in cache)
          Expanding AppDynamics Agent to .java-buildpack/app_dynamics_agent (0.7s)
   [AppDynamicsAgent]               INFO  Downloading override configuration files from http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/
   [AppDynamicsAgent]               INFO  Could not retrieve http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/logging/log4j2.xml.  Code: 404 Message: Not Found
   [AppDynamicsAgent]               INFO  Could not retrieve http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/logging/log4j.xml.  Code: 404 Message: Not Found
   [AppDynamicsAgent]               INFO  Could not retrieve http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/app-agent-config.xml.  Code: 404 Message: Not Found
   **[Buildpack]                      ERROR Finalize failed with exception #<RuntimeError: Unable to find cached file for http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/controller-info.xml>**
   Unable to find cached file for http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/controller-info.xml
   Failed to compile droplet: Failed to run finalize script: exit status 1

@nebhale This issue surfaced recently for our customers. Wondering if caching mechanism changed recently

[nebhale]

It appears that those files are not visible to the buildpack. The HTTP request was completed successfully but resulted in a 404.

Could not retrieve http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/logging/log4j2.xml.  Code: 404 Message: Not Found

[hp685]

@nebhale yes those are INFO messages and indicate that those files were not meant to be overridden. For the particular example controller-info.xml was the only file meant to be overridden (http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/) which results in a runtime error:

   **[Buildpack]                      ERROR Finalize failed with exception #<RuntimeError: Unable to find cached file for http://appd-configuration-server.apps.hiddenhills.cf-app.com/v1/java/controller-info.xml>**

[hp685]

Thanks @nebhale for the fix!