https://github.com/rabobank/cf-metrics-exporter
Export custom metrics from Java application to Cloud Foundry metrics endpoint
https://github.com/rabobank/cf-metrics-exporter
cloudfoundry javaagent jvm metrics-exporter
Last synced: 9 months ago
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Export custom metrics from Java application to Cloud Foundry metrics endpoint
- Host: GitHub
- URL: https://github.com/rabobank/cf-metrics-exporter
- Owner: rabobank
- License: apache-2.0
- Created: 2025-05-26T08:51:56.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-09-01T14:04:17.000Z (9 months ago)
- Last Synced: 2025-09-01T14:40:59.860Z (9 months ago)
- Topics: cloudfoundry, javaagent, jvm, metrics-exporter
- Language: Java
- Homepage:
- Size: 105 KB
- Stars: 3
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# cf-metrics-exporter
A JVM agent to send custom metrics to the cloud foundry custom metrics endpoint.
This also counts the container-to-container traffic and can be used for autoscaling.
The purpose of this agent:
* parse autoscaler endpoint info from VCAP_SERVICES
* collect RPS (Requests Per Second) from the application
* send RPS to cloud foundry custom metrics endpoint
Sends custom metric with name `custom_throughput` and unit: `rps`.
(Cloud Foundry auto scaler has a `throughput` metric.)
The RPS is calculated as an average over the configured interval (default 10 seconds).
### Spring Boot RPS
Transform these classes with ByteBuddy on SpringBoot API to count request/reply:
* org.springframework.web.servlet.DispatcherServlet#handle
* org.springframework.web.reactive.DispatcherHandler#handle
No need to enable Tomcat MBeans via application settings
Works for all Spring Boot servers:
* Netty (WebFlux/Reactor)
* Tomcat (also with virtual threads)
* Undertow
Use `rspType=spring-request` to enable this feature (default).
### Tomcat RPS
For Tomcat use the JMX MBean and Attribute:
* `Tomcat:type=GlobalRequestProcessor,name="http-nio-8080"` (or similar, depending on your Tomcat configuration)
* `Attribute: requestCount`
Needs explicit application setting: `server.tomcat.mbeanregistry.enabled=true`
Use `rspType=tomcat-mbean` to enable this feature.
### Random RPS
This is a random RPS generator, useful for testing purposes. It generates a random number of requests per second.
Use `rspType=random` to enable this feature.
## Agent usage
Copy the jar to the CF container and activate it via the `-javaagent` option.
In the `manifest.yml` file, add the following:
-javaagent:/path/to/cf-metrics-exporter-.jar
with settings:
-javaagent:/path/to/cf-metrics-exporter-.jar=debug,rpsType=random,intervalSeconds=5
## Agent Settings
The following settings are available:
- `debug`: Enable debug logging.
- `rpsType`: Type of RPS to use. Options are `spring-request` (default), `random`, `tomcat-mbean`.
- `intervalSeconds`: Interval in seconds for sending metrics. Default is 10 seconds. Note: the average RPS is calculated for every interval.
- `metricsEndpoint`: The endpoint to send metrics to. Not used currently, will pick it up from VCAP_SERVICES.
Run with debug enabled to see stacktraces of exceptions.
## Env variables
The following environment variables are used from within the cloud foundry container:
- VCAP_APPLICATION
- VCAP_SERVICES
- CF_INSTANCE_INDEX
The VCAP_SERVICES should contain the custom metrics endpoint and basic auth credentials. mTLS is not supported.
There is a `src/test/resources/test.env` file that can be used to set these variables for local testing.
The `src/test/resources/test-missing-basic-auth.env` can be used to test with mTLS instead of basic auth.
Use via `source src/test/resources/test.env` in your terminal or add as env file in the IDE runner.
## Build
To build the project, use the following command:
```bash
./mvnw clean package
```
The agent jar will be created in the `target` directory: `target/cf-metrics-exporter-LOCAL-SNAPSHOT.jar`
## Test metrics endpoint
A Wiremock server is included to test the agent. It can be used with basic-auth (port 58080) and mTLS (port 58443).
The certificates for mTLS are generated with the `mtls-certs/mtls-certificate-setup.sh` script.
This script is executed in the compile step of the Maven build.
The certs are in `target/generated-certs`.
Beware: the client private key is not exactly the same as the ones used in cloud foundry,
so parse errors were present when reading the private key on cloud foundry. The bouncy castles
library is currently included for the correct parsing of the client private key. This was
the error without bouncy castles:
```
Failed to load private client key Caused by: java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException : algid parse error, not a sequence Caused by: java.security.InvalidKeyException: IOException : algid parse error, not a sequence
```
# Notes
This is a "Beta" release, feedback is welcome!