@dynrl/drl-settings/lib/index.js

Standardizes settings access

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const env = require('dotenv');
const fs = require('fs');
const path = require('path');
/**
 * Wrapper for accessing settings in DRL apps and modules.
 */
class DrlSettings {
    /**
     * Detects if importing .env files is allowed. This requires that the
     * environment variable DRL_HOST_ENV be set to CI or LOCAL.
     */
    static useEnvFile() {
        // This is a environmental setting emitted in azure instances. Hopefully
        // we can rely on it to
        return process.env['DRL_HOST_ENV'] === 'CI' ||
            process.env['DRL_HOST_ENV'] === 'LOCAL';
    }
    /**
     * Initializes and validates anticipated keys.
     * @param keys - A list of keys that are going to be used
     * @param filePath - An optional
     */
    static initSettings(keys, filePath) {
        if (!keys || keys.length === 0) {
            this.warn('No keys defined... This call has no effect!');
        }
        // Add keys to white list
        keys.forEach(k => {
            this.WhiteList[k] = true;
        });
        // When running on azure, we should rely on the app settings instead of env files.
        // This ensures that the creation of app settings are intentional.
        if (this.useEnvFile() && filePath) {
            filePath = path.resolve(filePath);
            if (!fs.existsSync(filePath)) {
                throw new Error(`Could not locate .env file at ${filePath}`);
            }
            this.log(`Looking for .env file at ${filePath}.`);
            env.config({ path: filePath });
        }
        // Validate that provided keys now exist in process.env
        this.checkKeys(keys);
    }
    /**
     * Lists all available keys
     */
    static getSettingKeys() {
        let result = new Array();
        for (const key in this.WhiteList) {
            if (this.WhiteList.hasOwnProperty(key) &&
                process.env.hasOwnProperty(key)) {
                result.push(key);
            }
        }
        return result;
    }
    /**
     * Grabs setting value for a given key.
     * @param key - key to look up
     * @throws - If key has not be properly registered or doesn't exist in process.env
     */
    static getSetting(key) {
        if (!this.WhiteList[key]) {
            throw new Error(`Non-sanctioned key detected, ${key}. Make sure keys are registered during the initSettings call.`);
        }
        const val = process.env[key];
        if (val == null) {
            throw new Error(`Could not locate required setting, ${key}. Add this to your environment variables.`);
        }
        if (val === '') {
            this.warn(`Empty key detected, ${key}.`);
        }
        return val;
    }
    static warn(msg) {
        console.warn(`DrlSettings: ${msg}`);
    }
    static log(msg) {
        console.log(`DrlSettings: ${msg}`);
    }
    static checkKeys(keys) {
        keys.forEach(k => {
            if (process.env[k] === void 0) {
                throw new Error(`Missing key detected ${k}`);
            }
            if (process.env[k] === '') {
                throw new Error(`Empty key detected ${k}`);
            }
        });
    }
}
DrlSettings.WhiteList = {};
exports.DrlSettings = DrlSettings;
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