115 lines
3.8 KiB
Markdown
115 lines
3.8 KiB
Markdown
## Spring-boot + JDBC (MySQL) example
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### Purpose
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This project aims at demonstrating how to instrument legacy code based on the SpringBoot framework
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and a MySQL JDBC connection.
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We are using the [opentracing contributions](https://github.com/opentracing-contrib) in order to trace:
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* All the JDBC queries and calls to the DB
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* All incoming HTTP calls
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The instrumentation is injected via the Datadog Java Agent. Java agents allows developers to execute
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some code before starting the legacy application. All operations for instrumenting the code are done
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at this time.
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### Run the demo
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The demo consistes into a very simple backend backed by a MySQL db. The Spring Boot application exposes
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2 endpoints that can be reached via an HTTP request.
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#### Prerequisites
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1. Run the latest version of Datadog Agent. For instance, you can run it through a docker container:
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`docker run -d --name dd-agent -v /var/run/docker.sock:/var/run/docker.sock:ro -v /proc/:/host/proc/:ro -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro -e API_KEY=<YOUR-API-KEY> -e SD_BACKEND=docker -p 8126:8126 -P datadog/docker-dd-agent:latest`
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#### Run the application
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The first step is to edit the Spring configuration file and the Datadog Tracer file and check if the
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connection properties are okay.
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```properties
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# file: src/resources/application.properties
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spring.datasource.driver-class-name= io.opentracing.contrib.jdbc.TracingDriver
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spring.datasource.url= jdbc:tracing:mysql://localhost:3306/springdb
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spring.datasource.username=root
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spring.datasource.password=root
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```
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```yaml
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# file: src/resources/dd-trace.yaml
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# Service name used if none is provided in the app
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defaultServiceName: spring-app
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# The writer to use.
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writer:
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type: DDAgentWriter
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host: localhost
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port: 8126
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# The sampler to use.
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sampler:
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type: AllSampler
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```
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Then, is to run the Spring Application along the Datadog Java Agent.
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- So first download the `jar` file from the main repository.
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*NOTE:* While in beta, the latest version is best found on the [Snapshot Repo](https://oss.jfrog.org/artifactory/oss-snapshot-local/com/datadoghq/).
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```
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# download the latest published version:
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wget -O dd-java-agent.jar 'https://search.maven.org/remote_content?g=com.datadoghq&a=dd-java-agent&v=LATEST'
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```
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- Then add the following JVM argument when launching your application (in IDE, using Maven/Gradle run or simply in collaboration with the `>java -jar` command):
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```
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-javaagent:/path/to/the/dd-java-agent.jar
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```
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- Finally, build and run the application with the `javaagent` option. (Note, actual flag set in `spring-boot-jdbc.gradle`)
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```
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cd path/to/dd-trace-examples/spring-boot-jdbc
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./gradlew bootRun -Pjavaagent=/path/to/the/dd-java-agent.jar
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```
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### Generate traces
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Once the application runs. Go to the following urls:
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* [http://localhost:8080/demo/add?name=foo&email=bar](http://localhost:8080/demo/add?name=foo&email=bar)
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* [http://localhost:8080/demo/all](http://localhost:8080/demo/all)
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Then, you will able to see traces directly to the DataDog UI.
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### How did we instrument this project?
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If you want to instrument your own code (Spring-boot and JDBC based), here is how you should do it.
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#### Dependencies
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#### Auto-instrumentation with the `dd-trace-agent`
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The instrumentation is entirely done by the datadog agent which embed a set of rules that automatically recognizes & instruments:
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- The java servlet filters
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The datadog agent embeds the [open tracing java agent](https://github.com/opentracing-contrib/java-agent).
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JDBC is not automatically instrumented yet by the agent. So you should follow the instructions on the next section.
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#### JDBC tracing configuration
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Just edit your `application.properties` [file](src/main/resources/application.properties)
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and add `:tracing` right after the `jdbc` string as shown below.
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```properties
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spring.datasource.url= jdbc:tracing:mysql://localhost:3306/springdb
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```
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