ecoCode-rule-validator-js-cadvisor

JS Rules validator using cadvisor

Install prerequisites

You can run the code in a VSCODE devcontainer, which will launch the PostGres database and the metrics service cAdvisor

You need to have Docker, Node, VSCode, and the Dev Container extension installed on your machine.

Context

The tests run in a docker container. The database is running in another container on the docker network. The monitoring is realized through another container running cAdvisor

Running containers:

• the Node.js container with the test script, and uses pg as a driver to connect to the database,
• the Postgres container with the database,
• the cAdvisor container to monitor the execution and get the relevant data.

graph TD
    A[Node.js container] -->|Connects to| B(Postgres container)
    A -->|Calls API| C(cAdvisor container)
    B -->|Stores data in| D(Postgres docker volume)
    C -->|Returns data| A

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Tools

• Node.js
• Docker
• Postgres
• cAdvisor

Structure

.devcontainer

The code is run in a devcontainer for VSCode. If you do not use VSCode and want to run the code in another container, you need to:

1. Create a Dockerfile to build your project and run it in a Node container.
2. Use the Dockerfile in the docker-compose.yml file instead of the devcontainer's image.

There is a tutorial available here that you can read and adapt to your needs: Use containers for Node.js development

db/db.js

The default export is the driver that connects to the the database. Just use db.query() to run a SQL query.

monitoring

monitoring.api.js

This contains the code to connect to the cAdvisor API using node-fetch.

• setStartDate: You need to set a start time BEFORE the test
• getMonitoringData: get the raw statistic events from cAdvisor AFTER the test

stat.js

Using stats you can:

• getStats: pass the raw events you got from getMonitoringData to get usable statistics
• diffStats: pass two statistic objects to get the difference between the two. Useful to compare test scenarii
• displayStats: pass the statistic object to log it in the console

src

This is where you should put the files for your test.

utils

• delay: pass a number in milliseconds to wait in the process

Usage

You can edit the postgres user in the .dockercontainer/.env file.

You should do the following steps for your test:

1. Write the code you need in src a. Do not forget to set a time with setStartDate before the test. b. Run the test. c. Get the monitoring data with getMonitoringData after the test, then get the statistics with getStats. d. Use the pino logger to log the results both in console and in file.
2. Execute the code in the root index.js file.
3. Run the code in the devcontainer with npm start to see the results.
4. Find the logs in the logs folder or in the console.

Metrics

The data is fetched through the REST API of the cAdvisor container. The 1.3 API's documentation is here: cAdvisor API. It is a bit limited, but you can observe what data is returned if you need more, or dig through the GO code here: container.go . There is also a web UI available at http://localhost:8080 where you can see more data: cAdvisor Web UI.

We measure the following data:

• CPU total usage: Amount of time for which the CPU was used for processing instructions in nanoseconds.
• CPU user usage: Same as befor but in the user space.
• Memory usage: Memory usage of the container in bytes.
• Network RX: Measure the amount of network traffic received by the container in bytes.
• Network TX: Measure the amount of network traffic transmitted by the container in bytes.