Function registerConfigureHook

Register a callback configure hook to automatically add callback handlers to all runs.

There are two ways to use this:

1. Using a context variable:

   • Set contextVar to specify the variable name
   • Use setContextVariable() to store your handler instance

2. Using an environment variable:

   • Set both envVar and handlerClass
   • The handler will be instantiated when the env var is set to "true".

Example

// Method 1: Using context variable
import {
  registerConfigureHook,
  setContextVariable
} from "@langchain/core/context";

const tracer = new MyCallbackHandler();
registerConfigureHook({
  contextVar: "my_tracer",
});
setContextVariable("my_tracer", tracer);

// ...run code here

// Method 2: Using environment variable
registerConfigureHook({
  handlerClass: MyCallbackHandler,
  envVar: "MY_TRACER_ENABLED",
});
process.env.MY_TRACER_ENABLED = "true";

// ...run code here
Copy