Develop Reference

NestJS ConfigModule.forRoot load is not working as I expected

I am trying to get the load env variable functionality to work in ConfigModule in NestJS.
import { Module } from '#nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { ConfigModule } from '#nestjs/config';
#Module({
imports: [
ConfigModule.forRoot({
load: [
() => ({
port: 3000,
database: {
host: process.env.DATABASE_HOST,
port: parseInt(process.env.DATABASE_PORT, 10) || 5432,
},
}),
],
}),
],
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}
When I inspect process.env.port it is undefined. I have a feeling I am not understanding what this is actually doing. I thought it would be adding the env variable port and database. I think it may have something to do with expandable env variables which I don't understand how to access. Can someone explain how to get this to work and how to access these variables. The code above was taken from the NestJS documentation located at https://docs.nestjs.com/techniques/configuration
Thanks

Okay, as usual I answered my own question 15 minutes after I posted it. My assumption that this modified process.env was incorrect. It looks like it stores these values internally to the ConfigModule and they are accessible through the ConfigService.
this.configService.get<number>('port') // returns 3000
process.env.port // returns undefined
I will leave this up here if it helps someone else. You know what they say about assuming.
Thanks

Best practice to use config service in NestJS Module

I want to use environment variables to configure the HttpModule per module, from the docs I can use the configuration like this:
#Module({
imports: [HttpModule.register({
timeout: 5000,
maxRedirects: 5,
})],
})
But I don't know what is the best practice to inclue a baseURL from environment vairable (or a config service), for example like this:
#Module({
imports: [HttpModule.register({
baseURL: this.config.get('API_BASE_URL'),
timeout: 5000,
maxRedirects: 5,
})],
The this.config is undefined here cause it's out of class.
What is the best practice to set baseURL from environment variables (or config service)?

Update Jan 19
HttpModule.registerAsync() was added in version 5.5.0 with this pull request.
HttpModule.registerAsync({
imports:[ConfigModule],
useFactory: async (configService: ConfigService) => ({
baseURL: configService.get('API_BASE_URL'),
timeout: 5000,
maxRedirects: 5,
}),
inject: [ConfigService]
}),
Original Post
This problem was discussed in this issue. For the nestjs modules like the TypeOrmModule or the MongooseModule the following pattern was implemented.
The useFactory method returns the configuration object.
TypeOrmModule.forRootAsync({
imports:[ConfigModule],
useFactory: async (configService: ConfigService) => ({
type: configService.getDatabase()
}),
inject: [ConfigService]
}),
Although Kamil wrote
Above convention is now applied in all nest modules and will be
treated as a best practice (+recommendation for 3rd party modules).
More in the docs
it does not seem to be implemented for the HttpModule yet, but maybe you can open an issue about it. There are also some other suggestions in the issue I mentioned above.
Also have a look at the official docs with best practices on how to implement a ConfigService.

Although the top rated answer to this question is technically correct for most implementations, users of the #nestjs/typeorm package, and the TypeOrmModule should use an implementation that looks more like the below.
// NestJS expects database types to match a type listed in TypeOrmModuleOptions
import { TypeOrmModuleOptions } from '#nestjs/typeorm/dist/interfaces/typeorm-options.interface';
#Module({
imports: [
ConfigModule.forRoot({
isGlobal: true,
load: [mySettingsFactory],
}),
TypeOrmModule.forRootAsync({
imports: [ConfigModule],
useFactory: async (configService: ConfigService) => ({
type: configService.get<TypeOrmModuleOptions>('database.type', {
infer: true, // We also need to infer the type of the database.type variable to make userFactory happy
}),
database: configService.get<string>('database.host'),
entities: [__dirname + '/**/*.entity{.ts,.js}'],
synchronize: true,
logging: true,
}),
inject: [ConfigService],
}),
],
controllers: [],
})
export class AppRoot {
constructor(private connection: Connection) {}
}
The major thing this code is doing is retrieving the correct typings from TypeORM (see the import) and using them to hint the return value configService.get() method. If you don't use the correct TypeORM typings, Typescript would get mad.

I also encountered several issues with implementing a ConfigService as described in the NestJS documentation (no type-safety, no modularity of configuration values, ...), I wrote down our company's final NestJS configuration management strategy in great detail here: NestJS Configuration Management
The basic idea is to have a central config module that loads all configuration values from the processes' environment. However, instead of providing a single service to all modules, each module can inject a dedicated subset of the configuration values! So each module contains a class that specifies all configuration values that this module needs to be provided at runtime. This simultaneously gives the developer type-safe access to configuration values (instead of using string literals throughout the codebase)
Hope this pattern also works for your use-case :)

Great answer by #Kim Kern, which clearly goes over injection of the ConfigService into a module configuration, that might be dependent on environment variables; however, from my personal experience, your app-root module or some other module with a couple of imports might get crowded and/or hard to read as well as understand the imports, module configuration and what the module you are defining relies on. So, thanks to Jay McDoniel, who curated me on this question, you can move configuration logic into a separate file.
First Solution
Example of app.module.ts:
import { Module } from '#nestjs/common';
import { ConfigModule } from '#nestjs/config';
import { MikroOrmModule } from '#mikro-orm/nestjs';
import { AppService } from './users.service';
import { AppController } from './users.controller';
import { get_db_config } from './config/database.config';
#Module({
imports: [
ConfigModule.forRoot({
isGlobal: true,
expandVariables: true,
}),
MikroOrmModule.forRootAsync( get_db_config() ),
],
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}
Example of config/database.config.ts:
import { MikroOrmModuleAsyncOptions } from "#mikro-orm/nestjs";
import { ConfigService } from "#nestjs/config";
export function get_db_config(): MikroOrmModuleAsyncOptions
{
return {
useFactory: (configService: ConfigService) =>
({
dbName: 'driver',
type: 'postgresql',
host: configService.get('DB_HOST'),
port: configService.get('DB_PORT'),
user: configService.get('DB_USERNAME'),
password: configService.get('DB_PASSWORD'),
autoLoadEntities: true
}),
inject: [ConfigService]
}
}
However, NestJS Docs - Configuration Namespaces as well as NestJS Authentication and Authorization Course provide an alternative method of solving this issue.
Second Solution
Example of auth.module.ts:
import { Module } from '#nestjs/common';
import { ConfigModule } from '#nestjs/config';
import { JwtModule } from '#nestjs/jwt';
import jwtConfig from './jwt.config';
#Module({
imports: [
ConfigModule.forFeature( jwtConfig ),
JwtModule.registerAsync( jwtConfig.asProvider() ),
]
})
export class AuthModule {}
Example of jwt.config.ts:
import { registerAs } from "#nestjs/config"
export default registerAs('jwt', () => {
return {
secret: process.env.JWT_SECRET,
issuer: process.env.JWT_TOKEN_ISSUER,
accessTokenTtl: parseInt(process.env.JWT_TOKEN_TTL)
};
});

Set up Angular 6 environment variables from .env

There's an angular 6 project using environment variables from ./project/src/environments/environment.prod.ts
export const environment = {
production: true,
testVar: 'gg',
};
The backend for this project also has env variables in a .env file, so a lot of variable duplicate angular env variables. It would be nice to have something like
export const environment = {
production: true,
testVar: process.env.TEST_VAR
};
, so I didn't have to duplicate variables.
ie
I'd like to parse variables from a .env file and assign their values to angular env variables during typescript compilation on the server.
How can this be done?
Maybe with webpack?
UPDATE
Some clarification. My .env file contains no json. It looks like this:
TEST_VAR=1
UPDATE
Since ng eject is not available for Angular 6, I don't seem to be able to hack into webpack config. Looks like deadend here.
ng eject
Overview
Temporarily disabled.
Ejects your app and output the
proper webpack configuration and scripts.

This question becomes also more and more important, when we want to containerize angular applications.
My research lead me to an idea, where I have to write a little node.js or typescript program, using dotenv for reading .env file and create the environment.ts file at buildtime, before starting ng serve.
You can create entries in the package.json like this:
...
"config": "ts-node set-env.ts",
"server": "npm run config && ng serve"
...
and run it with
npm run server
Here is a good explanation with an example typescript file:
https://medium.com/#ferie/how-to-pass-environment-variables-at-building-time-in-an-angular-application-using-env-files-4ae1a80383c

You can create a config file and populate in Run-time.
1) create a File(app-config.json) in assets folder with your variables
{ "servicesUrl": "https://localhost:8080/api"}
2) create a service (AppConfigService ) to read the file.
#Injectable()
export class AppConfigService {
private appConfig;
constructor (private injector: Injector) { }
loadAppConfig() {
let http = this.injector.get(HttpClient);
return http.get('/assets/app-config.json')
.toPromise()
.then(data => {
this.appConfig = data;
})
}
get config() {
return this.appConfig;
}
3) Next we need to tell our application to execute the loadAppConfig() method of our service.
import { NgModule, APP_INITIALIZER } from '#angular/core';
import { AppConfigService } from './services/app-config.service';
#NgModule({
...,
providers: [
AppConfigService,
{
provide: APP_INITIALIZER,
useFactory: appInitializerFn,
multi: true,
deps: [AppConfigService]
}
],
...
})
export class AppModule { }
4) create a function called "appInitializerFn" to call our service in AppModule (app.module.ts)
const appInitializerFn = (appConfig: AppConfigService) => {
return () => {
return appConfig.loadAppConfig();
}
};
...
#NgModule({
...
})
export class AppModule {}
5) import environment and use it :example
import { Injectable } from '#angular/core';
import { HttpClient } from '#angular/common/http';
import { AppConfigService } from './services/app-config.service';
#Injectable()
export class DataContextService {
basePath: string;
constructor (private environment: AppConfigService, private http: HttpClient) {
this.basePath = environment.config.servicesBasePath;
}
getNames() {
return this.http.get(this.basePath + '/names/');
}
}
for more information please see:
link

If you want to use variables in build time you could use dotenv
As early as possible in your application, require and configure dotenv.
require('dotenv').config()
Create a .env file in the root directory of your project. Add environment-specific variables on new lines in the form of NAME=VALUE. For example:
DB_HOST=localhost
DB_USER=root
DB_PASS=s1mpl3

Switch from mock backend to real backend on application start

I have an Angular 5 application that I want to be able to start from either a mock backend or a real backend depending on an environment variable.
This is my environment file:
export const environment = {
production: false,
mockBackend: true
};
I want to be able to have this sort of structure:
AppModule
SharedAppModules
AppModule, imports SharedAppModules and adds what is necessary.
MockAppModule, imports SharedAppModules and adds what is necessary:
MockBackendService,
MockBackend,
BaseRequestOptions,
{ provide: LocationStrategy, useClass: HashLocationStrategy },
{
provide: Http,
deps: [MockBackend, BaseRequestOptions],
useFactory: mockHttpFactory
}
My goal would be to do in main.ts:
if (environment.production) {
enableProdMode();
}
if(environment.mockBackend) {
platformBrowserDynamic().bootstrapModule(MockAppModule);
} else {
platformBrowserDynamic().bootstrapModule(AppModule);
}
But I have an error from Angular saying it did not find anything to bootstrap. Has anybody already tried to do the same thing or have any idea to achieve the same goal differently?

Save the log in electron devtools to a file

I am working on Electron app with angular 5 for the rendering process,
is there is a way to export the console programmatically?
I need a way to synchronize the logging data to file so, I can review it anytime
without opening electron devtools and save as option, I need it programmatically
I save my own logs, but what if there is a module that logging an error i need to get whole console log history and export it to log file

You can use electron-log, which is a logging module for Electron application. It can be used without Electron.
And you should use ngx-electron.
Firstly, install electron-log
npm install electron-log
Require it in the electron's main process.
const logger = require('electron-log');
Then install ngx-electron
npm install ngx-electron
ngx-electron is exposing a module called NgxElectronModule which needs to be imported in your AppModule.
import {NgModule} from '#angular/core';
import {BrowserModule} from '#angular/platform-browser';
import {NgxElectronModule} from 'ngx-electron';
import {AppComponent} from './app.component';
#NgModule({
declarations: [],
imports: [
BrowserModule,
NgxElectronModule
],
bootstrap: [AppComponent]
})
export class AppModule {
}
Once the module has been imported, you can easily use angular DI to ask for ElectronService.
import {Component} from '#angular/core';
import {ElectronService} from 'ngx-electron';
#Component({
selector: 'my-app',
templateUrl: 'app.html'
})
export class AppComponent {
logger
constructor(private _electronService: ElectronService) {
// this should be in init()
if(this._electronService.isElectronApp) {
this.logger = this._electronService.remote.require("electron-log");
}
}
public testLogger() {
this.logger.info('this is a message from angular');
}
}
After that, you should be able to use electron-log in your components, just remember import {ElectronService} from 'ngx-electron';, and this.logger = this._electronService.remote.require("electron-log"); in the components.