Test Locally with ngrok

Create a Public Address by Tunneling to Your Localhost

What is ngrok?

ngrok exposes your local server (e.g. localhost:3000) to the public Internet. You can sign up for a free account here.

Note: ngrok exposes your local environment beyond the firewall and NAT of your machine. Even though the environment is exposed through a secure HTTP connection, there can be security vulnerabilities if the public address of your ngrok endpoint is not secured by authorization. Adding Authorization headers to your database or endpoint is recommended to properly test with ngrok.

Add ngrok to Your Local Database for the @dbquery Directive

Install ngrok on your machine by following the instructions in the ngrok dashboard, or run the following brew installation command:

brew cask install ngrok

If you choose to use the brew command, there is a forum here, that can support you with any errors you may run into while installing it.

Create the StepZen Schema

If you already have a StepZen schema, skip to PostgreSQL or MySQL, depending on the database you are testing.

Follow the steps below to create a StepZen schema:

  1. Generate the StepZen schema:

Mac

mkdir StepZen;
cd StepZen;
touch config.yaml;
touch postgres.graphql;
touch index.graphql

Windows

mkdir StepZen;
cd StepZen;
type nul >> "config.yaml";
type nul >> "postgres.graphql";
type nul >> "index.graphql"
  1. Open index.graphql in your code editor, and add database.graphql to your SDL:
schema
  @sdl(
    files: [
      "database.graphql"
    ]
  ) {
  query: Query
}

PostgreSQL

The following subsections describe how to install and use PostgreSQL with ngrok:

Install PostgreSQL

Follow the steps below to install PostgreSQL locally and test it using ngrok:

Note:

Ensure you have ngrok installed on your machine before continuing.

If you already have a PostgreSQL database running locally, skip to Point ngrok to your Local PostgreSQL Server.

The following steps are for macOS. If you are using Windows, Chocolatey follows a similar installation method.

  1. (Optional) Install pgAdmin if you want to see your database outside of the CLI.

  2. Install PostgreSQL on macOS using HomeBrew:

brew install postgresql
  1. Start the PostgreSQL server:
brew services start postgresql
  1. Install psql to run PostgreSQL commands:
brew link --force libpq
  1. Verify that PostgreSQL is installed:
Your-MacBook-Pro:sz-ngrok yourname$ psql --version
psql (PostgreSQL) 13.3
  1. Access your PostgreSQL server in the CLI:
psql postgres
  1. Create a table in the database by pasting the following in front of postgres-#, which is now running in your command line:
CREATE TABLE weather (
    city            varchar(80),
    temp_lo         int,           -- low temperature
    temp_hi         int,           -- high temperature
    prcp            real,          -- precipitation
    date            date
);

Point ngrok to your Local PostgreSQL Server

The PostgreSQL server is now running locally in your CLI.

Follow the steps below to point ngrok to your local PostgreSQL server:

  1. Run \conninfo in the PostgreSQL server to obtain details of the localhost session:
postgres=# \conninfo
You are connected to database "postgres" as user "testuser" via socket in "/tmp" at port "5432".
  1. Run the following command, changing the port to your unique generated port number. The PostgreSQL example above generated port 5432:
ngrok tcp 5432 // change 5432 to your port number

This command generates the TCP endpoint you will use later in config.yaml:

Session Status                online                                                                                                                                                                                                                          
Account                       Test Account                                                                                                                                                                                                         
Version                       2.3.40                                                                                                                                                                                                                          
Region                        United States (us)                                                                                                                                                                                                              
Web Interface                 http://127.0.0.1:1234                                                                                                                                                                                                           
Forwarding                    tcp://2.tcp.ngrok.io:1234 -> localhost:5432                                                                                                                                                                                    
                                                                                                                                                                                                                                                              
Connections                   ttl     opn     rt1     rt5     p50     p90                                                                                                                                                                                     
                              0       0       0.00    0.00    0.00    0.00 

Connect PostgreSQL to StepZen

From the information collected earlier via the \conninfo and ngrok tcp 5432 commands, let's add the PostgreSQL TCP endpoint along with the username and password from the database, to config.yaml for the schema.

Follow the steps below to connect PostgreSQL to StepZen:

  1. Copy the following configuration and add in your unique username, password, and TCP endpoint. If you are adding this configuration to an existing GraphQL schema, change the name of the configuration to match the name in your schema:
configurationset:
  - configuration:
      name: pg_config
      uri: postgresql://username:password@2.tcp.ngrok.io:1234/postgres

The endpoint in this uri configuration was generated by the ngrok command (ngrok tcp 5432) you ran earlier.

The username and password in the URI are the same login credentials you use to access the database.

In this example, the following endpoint is generated by ngrok:

2.tcp.ngrok.io:1234
  1. Append the database name to this TCP endpoint. In this example, the database is postgres:
2.tcp.ngrok.io:1234/postgres

With config.yaml properly configured, open the GraphQL schema file (e.g. database.graphql). In this example schema, there is one table in the database named weather:

postgres=# \c postgres
You are now connected to database "postgres" as user "root".
postgres=# \dt
           List of relations
 Schema |  Name   | Type  |   Owner    
--------+---------+-------+------------
 public | weather | table | root
(1 row)

The GraphQL schema below executes one mutation and one query to the PostgreSQL database:

  1. The createWeather mutation creates new rows in the weather table.
  2. The weather query retrieves all of the existing rows in the weather table.
type Weather {
  city: String
  temp_lo: Int
  temp_hi: Int
  prcp: Float
  date: Date
}

type Query {
  weather: [Weather]
    @dbquery(
      type: "postgresql"
      query: "select * from weather"
      configuration: "pg_config"
    )
}

type Mutation {
  createWeather(city: String!, temp_lo: Int!, temp_hi: Int!, prcp: Float!, date: Date!): Weather
    @dbquery(
      type: "postgresql"
      table: "weather"
      dml: INSERT
      configuration: "pg_config"
    )
}

MySQL

The following subsections describe how to install and use MySQL with ngrok:

Install MySQL

Follow the steps below to install MySQL locally and test it using ngrok:

Note:

If you already have a MySQL database running locally, skip to Point ngrok to your Local MySQL Server.

The following steps are for macOS. If you are using Windows, Chocolatey follows a similar installation method.

  1. Install MySQL:
brew install mysql
  1. Verify that MySQL is installed:
Your-MacBook-Pro:sz-ngrok username$ mysql --version
mysql  Ver 8.0.25 for macos10.15 on x86_64 (Homebrew)
  1. Start MySQL:
brew services start mysql
  1. Access the MySQL server:
mysql -u root -p password
  1. Create a new database and user:
mysql> create database tutorialdb;
Query OK, 1 row affected (0.00 sec)

mysql> create user 'tutorialuser'@'localhost' identified by 'tutorialuserpassword';
Query OK, 0 rows affected (0.01 sec)

mysql> grant all on tutorialdb.* to 'tutorialuser'@'localhost';
Query OK, 0 rows affected (0.01 sec)
  1. Exit the MySQL server and log in as the new user created in the previous step (e.g. tutorialuser:tutorialuserpassword):
mysql> exit

desktop % mysql -u tutorialuser -p tutorialdb
Enter password: ************ // tutorialuserpassword
  1. Create a table in the database:
mysql> CREATE TABLE weather (
    city            varchar(80),
    temp_lo         int,           -- low temperature
    temp_hi         int,           -- high temperature
    prcp            real,          -- precipitation
    date            date
);

Point ngrok to your Local MySQL Server

Follow the steps below to point ngrok to your local MySQL server:

  1. Determine where your MySQL database is running locally. There are many different ways to check where a program is running on a local machine by using grep, netstat, etc.

  2. Determine which port number MySQL is using:

mysql> SHOW VARIABLES WHERE Variable_name = 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.00 sec)

The following are alternative commands to check for port on a local machine:

mysql> SHOW GLOBAL VARIABLES LIKE 'port';
$ netstat -tlnp
  1. Set the port for ngrok to MySQL's port number. The MySQL example from above uses port 3306:
ngrok tcp 3306 // change 3306 to your port number

This command generates the TCP endpoint you will use later in config.yaml:

Session Status                online                                                                                                                                                                                                                          
Account                       Test Account                                                                                                                                                                                                         
Version                       2.3.40                                                                                                                                                                                                                          
Region                        United States (us)                                                                                                                                                                                                              
Web Interface                 http://127.0.0.1:1234                                                                                                                                                                                                           
Forwarding                    tcp://2.tcp.ngrok.io:1234 -> localhost:3306                                                                                                                                                                                    
                                                                                                                                                                                                                                                              
Connections                   ttl     opn     rt1     rt5     p50     p90                                                                                                                                                                                     
                              0       0       0.00    0.00    0.00    0.00 

Connect MySQL to StepZen

From the information collected earlier via the \port and ngrok tcp 3306 commands, let's add the MySQL TCP endpoint along with the username and password from the database, to config.yaml for the schema.

Follow the steps below to connect MySQL to StepZen:

  1. Copy the following configuration and add in your unique username, password, and TCP endpoint. If you are adding this configuration to an existing GraphQL schema, change the name of the configuration to match the name in your schema:
configurationset:
    - configuration:
      name: mysql_config
      dsn: tutorialuser:tutorialuserpassword@tcp(2.tcp.ngrok.io:1234)/tutorialdb

The endpoint in this dsn configuration was generated by the ngrok command (ngrok tcp 3306) you ran earlier.

The username and password are the same login credentials you use to access your database.

In this example, the following endpoint is generated by ngrok:

2.tcp.ngrok.io:1234
  1. Append the database name to this TCP endpoint. In this example, the database is tutorialdb:
2.tcp.ngrok.io:1234/tutorialdb

With config.yaml properly configured, open the GraphQL schema file (e.g. database.graphql). In this example, there is one table in my database named weather:

mysql> show tables;
+----------------------+
| Tables_in_tutorialdb |
+----------------------+
| weather              |
+----------------------+
1 row in set (0.00 sec)

The GraphQL schema below executes one mutation and one query to the tutorialdb database:

  1. The createWeather mutation creates new rows in the weather table.
  2. The weather query retrieves all of the existing rows in the weather table.
type Weather {
  city: String
  temp_lo: Int
  temp_hi: Int
  prcp: Float
  date: Date
}

type Query {
  weather: [Weather]
    @dbquery(
      type: "mysql"
      query: "select * from weather"
      configuration: "mysql_config"
    )
}

type Mutation {
  createWeather(city: String!, temp_lo: Int!, temp_hi: Int!, prcp: Float!, date: Date!): Weather
    @dbquery(
      type: "mysql"
      table: "weather"
      dml: INSERT
      configuration: "mysql_config"
    )
}

Add ngrok to a Local REST API Server

This section shows how to point ngrok to a local server and add the ngrok public address as an endpoint to the @rest directive. Since there are many ways to generate a REST API, this tutorial assumes that you have a REST API running on your localhost.

Note:

ngrok exposes the REST API to a public address, so restricting your REST API with authorization is recommended. The REST API operates on an HTTP protocol and can be proxied by ngrok as an HTTP endpoint.

Run the following command anywhere in the CLI to create an HTTP endpoint for the REST API local server:

ngrok http 8080 // change 8080 to your port number

This command generates the http endpoint you will use later in the StepZen schema:

Session Status                online                                                                                                                                                                                                                          
Account                       Test Account                                                                                                                                                                                                        
Version                       2.3.40                                                                                                                                                                                                                          
Region                        United States (us)                                                                                                                                                                                                              
Web Interface                 http://127.0.0.1:1234                                                                                                                                                                                                           
Forwarding                    http://1234addf9e2a9d.ngrok.io -> http://localhost:8080                                                                                                                                                                           
Forwarding                    https://1234addf9e2a9d.ngrok.io -> http://localhost:8080                                                                                                                                                                          
                                                                                                                                                                                                                                                              
Connections                   ttl     opn     rt1     rt5     p50     p90                                                                                                                                                                                     
                              0       0       0.00    0.00    0.00    0.00 

This ngrok command creates a secure public address on top of the local proxy on your machine. In the example above, this newly created ngrok endpoint is https://1234addf9e2a9d.ngrok.io.

In the StepZen schema, the @rest endpoint enables you to access the public address that has been generated:

"""
This is a dummy schema and should be replaced by your schema.
"""
type Sample {
  title: String!
}


type Query {
      restNgrok: [Sample]
        @rest(
            endpoint: "https://1234addf9e2a9d.ngrok.io"
            configuration: "sample"
        )
}

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