ExecutionContext is a lightweight Node.js package built with TypeScript that leverages AsyncLocalStorage to create a statically available context parallel to any execution. It provides a reliable, thread-safe context for attaching and accessing metadata throughout the lifecycle of an execution, such as API requests, background jobs, or message consumers. This allows various parts of your application to communicate and share metadata without needing to explicitly pass context objects.
npm install @clipboard-health/execution-context
This example demonstrates how to create a logging context, accumulate metadata from various function calls, and then log a single message containing all the gathered metadata.
import {
addMetadataToLocalContext,
getExecutionContext,
newExecutionContext,
runWithExecutionContext,
} from "@clipboard-health/execution-context";
export async function processRequest() {
// Start a context for this request
await runWithExecutionContext(newExecutionContext("context-name"), async () => {
const context = getExecutionContext();
try {
// Add metadata from the current function
addMetadataToLocalContext({ userId: "1" });
// Simulate calling other functions that add their own context metadata
callFunctionThatAddsContext();
callFunctionThatCallsAnotherFunctionThatAddsContext();
// Log the successful processing event with accumulated metadata
console.log("event=MessageProcessed", { ...context?.metadata });
} catch (error) {
// Capture and log error metadata if something goes wrong
addMetadataToLocalContext({ error });
console.error("event=MessageProcessed", { ...context?.metadata });
}
});
}
// Example function that adds its own metadata to the current context
function callFunctionThatAddsContext() {
addMetadataToLocalContext({ operation: "dataFetch", status: "success" });
}
// Example function that calls another function, both adding their own metadata
function callFunctionThatCallsAnotherFunctionThatAddsContext() {
addMetadataToLocalContext({ operation: "validate", validationStep: "pre-check" });
callAnotherFunctionThatAddsContext();
}
function callAnotherFunctionThatAddsContext() {
addMetadataToLocalContext({
operation: "validate",
validationStep: "post-check",
result: "passed",
});
}
See package.json scripts for a list of commands.