index.js

const load = async ({
    secretId = undefined,
    raiseException = true,
    debug = false,
    parseStringSecretToJSON = true,
    region = undefined,
    binarySecretDefaultKey = 'SMLOADER_BINARY_SECRET',
    stringSecretDefaultKey = 'SMLOADER_STRING_SECRET'
} = {}) => {
    const getEnvVar = (name, { boolType = false, defaultValue = undefined } = {}) => {
        if (name in process.env) {
            if (boolType) return process.env[name].toLowerCase() === 'true';
            else return process.env[name];
        }
        return defaultValue;
    }

    const SMLOADER_DEBUG = getEnvVar('SMLOADER_DEBUG', { boolType: true, defaultValue: debug });
    const SMLOADER_SECRET_ID = getEnvVar('SMLOADER_SECRET_ID', { defaultValue: secretId });
    const SMLOADER_RAISE_EXCEPTION = getEnvVar('SMLOADER_RAISE_EXCEPTION', { boolType: true, defaultValue: raiseException });
    const SMLOADER_PARSE_STRING_SECRET_TO_JSON = getEnvVar('SMLOADER_PARSE_STRING_SECRET_TO_JSON', { boolType: true, defaultValue: parseStringSecretToJSON });
    const SMLOADER_BINARY_SECRET_DEFAULT_KEY = getEnvVar('SMLOADER_BINARY_SECRET_DEFAULT_KEY', { defaultValue: binarySecretDefaultKey });
    const SMLOADER_STRING_SECRET_DEFAULT_KEY = getEnvVar('SMLOADER_STRING_SECRET_DEFAULT_KEY', { defaultValue: stringSecretDefaultKey });
    const SMLOADER_AWS_DEFAULT_REGION = getEnvVar('SMLOADER_AWS_DEFAULT_REGION', { defaultValue: region || getEnvVar('AWS_DEFAULT_REGION') });

    const finish = err => {
        if (SMLOADER_RAISE_EXCEPTION) {
            if (err instanceof String) throw new Error(err);
            else throw err;
        }
        if (SMLOADER_DEBUG) {
            console.log('Done');
        }
    }

    if (SMLOADER_DEBUG) {
        console.log('Initializing SM loader');
        console.log(`SMLOADER_DEBUG=${SMLOADER_DEBUG}`);
        console.log(`SMLOADER_SECRET_ID=${SMLOADER_SECRET_ID}`);
        console.log(`SMLOADER_RAISE_EXCEPTION=${SMLOADER_RAISE_EXCEPTION}`);
        console.log(`SMLOADER_PARSE_STRING_SECRET_TO_JSON=${SMLOADER_PARSE_STRING_SECRET_TO_JSON}`);
        console.log(`SMLOADER_BINARY_SECRET_DEFAULT_KEY=${SMLOADER_BINARY_SECRET_DEFAULT_KEY}`);
        console.log(`SMLOADER_STRING_SECRET_DEFAULT_KEY=${SMLOADER_STRING_SECRET_DEFAULT_KEY}`);
        console.log(`SMLOADER_AWS_DEFAULT_REGION=${SMLOADER_AWS_DEFAULT_REGION}`);
    }

    if (!SMLOADER_SECRET_ID) return finish('No secretId passed to secret manager loader');

    const parseStringSecretToEnv = data => {
        try {
            const json = JSON.parse(data);
            const keys = Object.keys(json);
            for (key of keys) {
                process.env[key] = json[key];
            }
        } catch (error) {
            return finish(error);
        }
    }

    const AWS = require('aws-sdk');
    const client = new AWS.SecretsManager({
        region: SMLOADER_AWS_DEFAULT_REGION
    });
    try {
        const data = await client.getSecretValue({
            SecretId: SMLOADER_SECRET_ID
        }).promise();
        if ('SecretString' in data) {
            const secret = data.SecretString;
            process.env[SMLOADER_STRING_SECRET_DEFAULT_KEY] = secret;
            if (SMLOADER_PARSE_STRING_SECRET_TO_JSON) {
                parseStringSecretToEnv(secret);
            }
        } else {
            const buff = Buffer.from(data.SecretBinary, 'base64');
            const decodedBinarySecret = buff.toString('ascii');
            process.env[SMLOADER_BINARY_SECRET_DEFAULT_KEY] = decodedBinarySecret;
        }
        if (SMLOADER_DEBUG) {
            console.log('SM Loader finished successfully');
        }
    } catch (error) {
        return finish(error);
    }
};

module.exports = {
    load
}