Behavior for token sources.

A token source is responsible for fetching access tokens from a specific authentication mechanism. Different sources implement different authentication flows (client assertion, managed identity, refresh token, etc.).

Implementing a Source

To implement a new source, create a module that implements the fetch_token/1 callback:

defmodule MyApp.CustomSource do
  @behaviour ExAzureIdentity.Source

  @impl true
  def fetch_token(config) do
    # Fetch token using custom logic
    {:ok, %{
      access_token: "...",
      expires_at: System.system_time(:second) + 3600,
      token_type: "Bearer",
      scope: "..."
    }}
  end
end

Token Format

The token map returned by fetch_token/1 must include:

• :access_token - The access token string
• :expires_at - Unix timestamp (seconds) when token expires
• :token_type - Token type (usually "Bearer")
• :scope - Optional scope string