Concurrency
Elixir Agents
Using Agents
Elixir Agents manage shared state with simple APIs.
Introduction to Elixir Agents
Elixir Agents provide a mechanism to manage shared state with minimal boilerplate. They offer a simple API to store and retrieve state, making them a convenient solution for scenarios where state needs to be shared across different processes.
Creating an Agent
To create an Agent, use the Agent.start_link/2 function. This function initializes the agent process with a given initial state. Here's a basic example:
In this example, the Agent is initialized with an empty map. The :ok tuple indicates that the agent was started successfully.
Updating Agent State
Agents allow you to update their state using the Agent.update/2 function. Here's how you can add a key-value pair to the agent's state:
The above code updates the existing state by adding a new key-value pair. The function passed to Agent.update/2 takes the current state and returns the updated state.
Fetching State from an Agent
To retrieve the current state from an Agent, use the Agent.get/2 function. Here's an example of how to fetch the state:
This code retrieves the value associated with :key from the agent's state.
Stopping an Agent
When you're done with an Agent, it's important to stop it to free up resources. Use the Agent.stop/1 function to gracefully terminate the agent:
Stopping an agent ensures that any resources it was using are released, preventing potential memory leaks.
Conclusion
Elixir Agents provide a simple yet powerful way to manage state across processes. They are an excellent choice for scenarios where you need to store state without the complexity of a full-blown GenServer. In this guide, we've covered creating, updating, fetching, and stopping agents, equipping you with the fundamental skills to use Agents effectively in your Elixir applications.
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