@aws-lambda-powertools/commons
Version:
A shared utility package for Powertools for AWS Lambda (TypeScript) libraries
109 lines (108 loc) • 3.98 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.isSdkClient = exports.addUserAgentMiddleware = exports.customUserAgentMiddleware = void 0;
const version_js_1 = require("./version.js");
const EXEC_ENV = process.env.AWS_EXECUTION_ENV || 'NA';
const middlewareOptions = {
relation: 'after',
toMiddleware: 'getUserAgentMiddleware',
name: 'addPowertoolsToUserAgent',
tags: ['POWERTOOLS', 'USER_AGENT'],
};
/**
* Type guard to check if the client provided is a valid AWS SDK v3 client.
*
* @internal
*/
const isSdkClient = (client) => typeof client === 'object' &&
client !== null &&
'send' in client &&
typeof client.send === 'function' &&
'config' in client &&
client.config !== undefined &&
typeof client.config === 'object' &&
client.config !== null &&
'middlewareStack' in client &&
client.middlewareStack !== undefined &&
typeof client.middlewareStack === 'object' &&
client.middlewareStack !== null &&
'identify' in client.middlewareStack &&
typeof client.middlewareStack.identify === 'function' &&
'addRelativeTo' in client.middlewareStack &&
typeof client.middlewareStack.addRelativeTo === 'function';
exports.isSdkClient = isSdkClient;
/**
* Helper function to create a custom user agent middleware for the AWS SDK v3 clients.
*
* The middleware will append the provided feature name and the current version of
* the Powertools for AWS Lambda library to the user agent string.
*
* @example "PT/Tracer/2.1.0 PTEnv/nodejs20x"
*
* @param feature The feature name to be added to the user agent
*
* @internal
*/
const customUserAgentMiddleware = (feature) => {
return (next) => async (args) => {
const existingUserAgent = args.request.headers['user-agent'] || '';
if (existingUserAgent.includes('PT/NO-OP')) {
const featureSpecificUserAgent = existingUserAgent.replace('PT/NO-OP', `PT/${feature}/${version_js_1.PT_VERSION} PTEnv/${EXEC_ENV}`);
args.request.headers['user-agent'] = featureSpecificUserAgent;
return await next(args);
}
if (existingUserAgent.includes('PT/')) {
return await next(args);
}
args.request.headers['user-agent'] =
existingUserAgent === ''
? `PT/${feature}/${version_js_1.PT_VERSION} PTEnv/${EXEC_ENV}`
: `${existingUserAgent} PT/${feature}/${version_js_1.PT_VERSION} PTEnv/${EXEC_ENV}`;
return await next(args);
};
};
exports.customUserAgentMiddleware = customUserAgentMiddleware;
/**
* Check if the provided middleware stack already has the Powertools for AWS Lambda
* user agent middleware.
*
* @param middlewareStack The middleware stack to check
*
* @internal
*/
const hasPowertools = (middlewareStack) => {
let found = false;
for (const middleware of middlewareStack) {
if (middleware.includes('addPowertoolsToUserAgent')) {
found = true;
}
}
return found;
};
/**
* Add the Powertools for AWS Lambda user agent middleware to the
* AWS SDK v3 client provided.
*
* We use this middleware to unbotrusively track the usage of the library
* and secure continued investment in the project.
*
* @param client The AWS SDK v3 client to add the middleware to
* @param feature The feature name to be added to the user agent
*/
const addUserAgentMiddleware = (client, feature) => {
try {
if (isSdkClient(client)) {
if (hasPowertools(client.middlewareStack.identify())) {
return;
}
client.middlewareStack.addRelativeTo(customUserAgentMiddleware(feature), middlewareOptions);
}
else {
throw new Error('The client provided does not match the expected interface');
}
}
catch (error) {
console.warn('Failed to add user agent middleware', error);
}
};
exports.addUserAgentMiddleware = addUserAgentMiddleware;