In the world of software development and system integration, the methods by which one system communicates with another can have a significant impact on the efficiency and responsiveness of the overall process. Two common approaches to this communication are polling and webhooks.
In the context of software, webhooks are HTTP callbacks that allow one system to notify another system of an event as soon as it happens. In the VCS and CI/CD scenario:
1. The VCS, such as GitHub, Bitbucket, or GitLab, has a webhook feature.
2. Whenever a code push occurs, the VCS sends an immediate HTTP POST request to the CI/CD server, saying, "Hey, new code just arrived!"
3. The CI/CD server responds instantly, starting the build and deployment process without wasting time checking repeatedly.
Here is a simplified example
Polling:
Imagine you're waiting for an important text message from a friend. To check if the message has arrived, you periodically take out your phone, unlock it, and open the messaging app to see if there's a new message. You keep doing this every few minutes until you finally see the message. This process is similar to polling in the context of software systems.
In software, polling is a method where a system (e.g., a Continuous Integration/Continuous Deployment server) repeatedly checks another system (e.g., a Version Control System) for updates. In your VCS and CI/CD scenario, it works like this:
1. CI/CD server regularly checks the VCS repository for code changes.
2. It repeatedly asks, "Is there new code? Is there new code?"
3. When it detects new code, it triggers the build and deployment process.
Webhooks:
Now, imagine you have a special notification setup with your friend. Instead of repeatedly checking your phone, your friend promises to send you a message as soon as anything important happens. So, you can put your phone aside and carry on with other tasks, only looking at it when you receive a notification. This is analogous to webhooks.
