Remove Heroku's Java Metrics Agent (#679)

buildpacks/jvm/CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Some error messages have changed so they longer suggest to open a Heroku support ticket. Instead, users are now provided with a link to create an issue on GitHub. ([#674](https://github.com/heroku/buildpacks-jvm/pull/674))
 
+### Removed
+
+- The buildpack no longer installs [Heroku's Java Metrics Agent](https://github.com/heroku/heroku-java-metrics-agent). It is only useful on the Heroku platform and can be installed by a dedicated buildpack in the future. ([#679](https://github.com/heroku/buildpacks-jvm/pull/679))
+
 ## [5.0.1] - 2024-05-23
 
 ### Changed

buildpacks/jvm/buildpack.toml

@@ -24,9 +24,5 @@ arch = "amd64"
 os = "linux"
 arch = "arm64"
 
-[metadata.heroku-metrics-agent]
-url = "https://repo1.maven.org/maven2/com/heroku/agent/heroku-java-metrics-agent/4.0.1/heroku-java-metrics-agent-4.0.1.jar"
-sha256 = "9a718680e4a93f93a8755b20fb21cc541e5c2692acc9da27c667530f48a716db"
-
 [metadata.release]
 image = { repository = "docker.io/heroku/buildpack-jvm" }

buildpacks/jvm/src/constants.rs

@@ -1,5 +1,3 @@
 pub(crate) const JAVA_TOOL_OPTIONS_ENV_VAR_DELIMITER: &str = " ";
 pub(crate) const JAVA_TOOL_OPTIONS_ENV_VAR_NAME: &str = "JAVA_TOOL_OPTIONS";
 pub(crate) const JDK_OVERLAY_DIR_NAME: &str = ".jdk_overlay";
-pub(crate) const SKIP_HEROKU_JVM_METRICS_AGENT_INSTALLATION_ENV_VAR_NAME: &str =
-    "SKIP_HEROKU_JVM_METRICS_AGENT_INSTALLATION";

buildpacks/jvm/src/errors.rs

@@ -1,6 +1,6 @@
 use crate::openjdk_artifact::HerokuOpenJdkVersionRequirement;
-use crate::{OpenJdkArtifactRequirementParseError, OpenJdkBuildpackError, ValidateSha256Error};
-use buildpacks_jvm_shared::log::{log_please_try_again, log_please_try_again_error};
+use crate::{OpenJdkArtifactRequirementParseError, OpenJdkBuildpackError};
+use buildpacks_jvm_shared::log::log_please_try_again_error;
 use buildpacks_jvm_shared::system_properties::ReadSystemPropertiesError;
 use indoc::formatdoc;
 use libherokubuildpack::log::log_error;
@@ -21,32 +21,6 @@ pub(crate) fn on_error_jvm_buildpack(error: OpenJdkBuildpackError) {
                     Heroku
             "},
         ),
-        OpenJdkBuildpackError::MetricsAgentDownloadError(error) => log_please_try_again_error(
-            "Heroku Metrics Agent download failed",
-            "Could not download Heroku Metrics Agent.",
-            error,
-        ),
-        OpenJdkBuildpackError::MetricsAgentSha256ValidationError(sha_256_error) => {
-            match sha_256_error {
-                ValidateSha256Error::CouldNotObtainSha256(error) =>
-                    log_please_try_again_error(
-                        "Heroku Metrics Agent download checksum error",
-                        formatdoc! {"
-                            Heroku Metrics Agent download succeeded, but an error occurred while verifying the
-                            SHA256 checksum of the downloaded file.
-                        "},
-                        error
-                    ),
-                ValidateSha256Error::InvalidChecksum { actual, expected } =>
-                    log_please_try_again(
-                        "Heroku Metrics Agent download checksum error",
-                        formatdoc! {"
-                            Heroku Metrics Agent download succeeded, but the downloaded file's SHA256
-                            checksum {actual} did not match the expected checksum {expected}.
-                        ", actual = actual, expected = expected },
-                    )
-            }
-        },
         OpenJdkBuildpackError::CannotCreateOpenJdkTempDir(error) => log_please_try_again_error(
             "Unexpected IO error",
             "Could not create temporary directory for the OpenJDK download due to an unexpected I/O error.",

buildpacks/jvm/src/layers/mod.rs

@@ -1,3 +1,2 @@
-pub(crate) mod heroku_metrics_agent;
 pub(crate) mod openjdk;
 pub(crate) mod runtime;

buildpacks/jvm/src/main.rs

@@ -5,30 +5,26 @@ mod openjdk_artifact;
 mod openjdk_version;
 mod util;
 
-use crate::constants::SKIP_HEROKU_JVM_METRICS_AGENT_INSTALLATION_ENV_VAR_NAME;
 use crate::errors::on_error_jvm_buildpack;
-use crate::layers::heroku_metrics_agent::HerokuMetricsAgentLayer;
 use crate::layers::openjdk::OpenJdkLayer;
 use crate::layers::runtime::RuntimeLayer;
 use crate::openjdk_artifact::{
     OpenJdkArtifactMetadata, OpenJdkArtifactRequirement, OpenJdkArtifactRequirementParseError,
 };
-use crate::util::{boolean_buildpack_config_env_var, ValidateSha256Error};
 use buildpacks_jvm_shared::system_properties::{read_system_properties, ReadSystemPropertiesError};
 pub(crate) use constants::{
     JAVA_TOOL_OPTIONS_ENV_VAR_DELIMITER, JAVA_TOOL_OPTIONS_ENV_VAR_NAME, JDK_OVERLAY_DIR_NAME,
 };
 use inventory::artifact::{Arch, Os};
 use inventory::inventory::{Inventory, ParseInventoryError};
 use libcnb::build::{BuildContext, BuildResult, BuildResultBuilder};
+use libcnb::buildpack_main;
 use libcnb::data::build_plan::BuildPlanBuilder;
 use libcnb::data::layer_name;
 use libcnb::detect::{DetectContext, DetectResult, DetectResultBuilder};
-use libcnb::generic::GenericPlatform;
+use libcnb::generic::{GenericMetadata, GenericPlatform};
 use libcnb::Buildpack;
-use libcnb::{buildpack_main, Platform};
 use libherokubuildpack::download::DownloadError;
-use serde::{Deserialize, Serialize};
 use std::env::consts;
 use url as _; // Used by exec.d binary
 
@@ -45,8 +41,6 @@ struct OpenJdkBuildpack;
 enum OpenJdkBuildpackError {
     UnsupportedOpenJdkVersion(OpenJdkArtifactRequirement),
     OpenJdkDownloadError(DownloadError),
-    MetricsAgentDownloadError(DownloadError),
-    MetricsAgentSha256ValidationError(ValidateSha256Error),
     CannotCreateOpenJdkTempDir(std::io::Error),
     CannotOpenOpenJdkTarball(std::io::Error),
     CannotDecompressOpenJdkTarball(std::io::Error),
@@ -61,7 +55,7 @@ enum OpenJdkBuildpackError {
 
 impl Buildpack for OpenJdkBuildpack {
     type Platform = GenericPlatform;
-    type Metadata = OpenJdkBuildpackMetadata;
+    type Metadata = GenericMetadata;
     type Error = OpenJdkBuildpackError;
 
     fn detect(&self, context: DetectContext<Self>) -> libcnb::Result<DetectResult, Self::Error> {
@@ -137,19 +131,6 @@ impl Buildpack for OpenJdkBuildpack {
             },
         )?;
 
-        libherokubuildpack::log::log_header("Installing Heroku JVM metrics agent");
-
-        if boolean_buildpack_config_env_var(
-            context.platform.env(),
-            SKIP_HEROKU_JVM_METRICS_AGENT_INSTALLATION_ENV_VAR_NAME,
-        ) {
-            libherokubuildpack::log::log_info(format!(
-                "Skipping agent installation, {SKIP_HEROKU_JVM_METRICS_AGENT_INSTALLATION_ENV_VAR_NAME} environment variable is set to a truthy value."
-            ));
-        } else {
-            context.handle_layer(layer_name!("heroku_metrics_agent"), HerokuMetricsAgentLayer)?;
-        }
-
         context.handle_layer(layer_name!("runtime"), RuntimeLayer)?;
 
         BuildResultBuilder::new().build()
@@ -160,18 +141,6 @@ impl Buildpack for OpenJdkBuildpack {
     }
 }
 
-#[derive(Deserialize, Debug)]
-struct OpenJdkBuildpackMetadata {
-    #[serde(rename = "heroku-metrics-agent")]
-    heroku_metrics_agent: HerokuMetricsAgentMetadata,
-}
-
-#[derive(Serialize, Deserialize, Clone, Debug, Eq, PartialEq)]
-struct HerokuMetricsAgentMetadata {
-    url: String,
-    sha256: String,
-}
-
 buildpack_main!(OpenJdkBuildpack);
 
 impl From<OpenJdkBuildpackError> for libcnb::Error<OpenJdkBuildpackError> {