First version
This commit is contained in:
Guillaume Polaert
parent
dce23a7517
commit
7881d7dd42
|
|
@ -0,0 +1,138 @@
|
||||||
|
## Datadog Java Tracer
|
||||||
|
|
||||||
|
### Motivations
|
||||||
|
|
||||||
|
The Datadog Java Tracer is an OpenTracing-compatible tracer. It provides all resources needed to instrument your code.
|
||||||
|
Opentracing introduces the concept of the *span*. A span is *timed operation* representing an action in the code.
|
||||||
|
The span can *be linked together*. And a trace is a list of spans, each related to the same top action/operation.
|
||||||
|
|
||||||
|
Let's see an example. When a client does a request on a Http Endpoint, asking for some BD resources,
|
||||||
|
Opentracing provides a way for measuring the time consumed for each operation:
|
||||||
|
|
||||||
|
````
|
||||||
|
TRACE:
|
||||||
|
|
||||||
|
client ---> HTTP Endpoint ---> DB Query/Result ---> Custom processing ---> client
|
||||||
|
|
||||||
|
SPAN 1 (Root Span) ................................................... (end) - 200ms
|
||||||
|
|--------SPAN 2 (Child of 1).................................(end) - 100ms
|
||||||
|
|-----------SPAN 3 (Child of 2).(end) - 50 ms
|
||||||
|
|----------------------------------------SPAN 4 (Child of 2)..(end) - 50 ms
|
||||||
|
````
|
||||||
|
|
||||||
|
This shows a very simple example of how works [Opentracing](http://opentracing.io/).
|
||||||
|
Here, the tracer produces a trace composed of 4 spans, each representing a specific action.
|
||||||
|
|
||||||
|
|
||||||
|
### How to load the Datadog Tracer (DDTrace) in the project?
|
||||||
|
|
||||||
|
The current implementation uses the trace-resolver feature provides by Opentracing.
|
||||||
|
That means you can add and load the tracer using a Java Agent directly with the JVM.
|
||||||
|
|
||||||
|
And then, the DDTrace can be configured using a YAML file: `dd-trace.yaml`.
|
||||||
|
By default, the DDTrace tries to reach a local Datadog Agent, but it can change by settings a different
|
||||||
|
location in the config file. Please, refer to the latest configuration template: [dd-trace.yaml](src/main/resources/dd-trace.yaml)
|
||||||
|
|
||||||
|
|
||||||
|
### How to use the Datadog Tracer (DDTrace) to instrument the code?
|
||||||
|
|
||||||
|
Once, the DDTrace is loaded, you can start to instrument your code using:
|
||||||
|
* The `@Trace` annotation,
|
||||||
|
* Or the Opentracing SDK.
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
This agent is build on the top of the [Open-Tracing contributions](https://github.com/opentracing-contrib/) and the [Datadog
|
||||||
|
tracer](https://github.com/DataDog/dd-trace-java).
|
||||||
|
|
||||||
|
At the moment, the Datadog Java Agent supports the following framework and librairies:
|
||||||
|
|
||||||
|
* Databases
|
||||||
|
* JDBC connections
|
||||||
|
* Mongo
|
||||||
|
* Elasticsearch
|
||||||
|
* Web servers and clients
|
||||||
|
* Spring Boot
|
||||||
|
* Jetty Server
|
||||||
|
* Tomcat Servlet
|
||||||
|
* Apache HTTP Client
|
||||||
|
* OkHttp
|
||||||
|
* Queueing
|
||||||
|
* JMS
|
||||||
|
* Third-party
|
||||||
|
* AMS SDK Client
|
||||||
|
|
||||||
|
#### Instrument your code
|
||||||
|
|
||||||
|
Here are the instructions.
|
||||||
|
Before start, make sure you have a running Datadog Agent with the [APM feature enabled](http://docs.datadoghq.com/tracing/).
|
||||||
|
|
||||||
|
1. Download the latest Datadog Java Agent version: https://mvnrepository.com/artifact/com.datadoghq/dd-java-agent.
|
||||||
|
```pom.xml
|
||||||
|
<dependency>
|
||||||
|
<groupId>com.datadoghq</groupId>
|
||||||
|
<artifactId>dd-java-agent</artifactId>
|
||||||
|
<version>${dd-trace.version}</version>
|
||||||
|
</dependency>
|
||||||
|
```
|
||||||
|
2. Add to the JVM the agent. This can be done by editing the command line or via the pom file.
|
||||||
|
```pom.xml
|
||||||
|
<plugin>
|
||||||
|
<groupId>org.apache.maven.plugins</groupId>
|
||||||
|
<artifactId>maven-surefire-plugin</artifactId>
|
||||||
|
<version>2.20</version>
|
||||||
|
<configuration>
|
||||||
|
<includes>
|
||||||
|
<include>*Test.java</include>
|
||||||
|
</includes>
|
||||||
|
<excludes>
|
||||||
|
<exclude>ElasticSearchInstrumentationTest.java</exclude>
|
||||||
|
</excludes>
|
||||||
|
<forkCount>3</forkCount>
|
||||||
|
<reuseForks>false</reuseForks>
|
||||||
|
<argLine>-javaagent:${M2_REPO}/com/datadoghq/dd-java-agent/${dd-trace.version}/dd-java-agent-${dd-trace.version}.jar</argLine>
|
||||||
|
<workingDirectory>target/FORK_DIRECTORY_${surefire.forkNumber}</workingDirectory>
|
||||||
|
</configuration>
|
||||||
|
</plugin>
|
||||||
|
|
||||||
|
```
|
||||||
|
|
||||||
|
|
||||||
|
### How it's work
|
||||||
|
### Dig deeper
|
||||||
|
|
||||||
|
|
||||||
|
Du coup le Readme.md de `java-trace` il faut un truc plutot simple qui expliqe que c la
|
||||||
|
librarie opentracing compliant de Datadog. Il faut expliquer aussi le resolver et son fichier `.yaml`
|
||||||
|
|
||||||
|
[10:41]
|
||||||
|
Prend peut etre exemple aussi sur une autre lib opentracing compliant
|
||||||
|
|
||||||
|
[10:41]
|
||||||
|
Peut etre expliquer ce que c’est un tracer, un span et un ou deux exemple d’instrumentation a la mano¡¡
|
||||||
Loading…
Reference in New Issue