Sending Email with SendGrid

This tutorial shows how to use SendGrid to send email from an application running on a Compute Engine instance. SendGrid is a third-party email service that offers Compute Engine users a free trial with 12,000 transactional emails free each month.

Objectives

• Use SendGrid with Postfix on a Compute Engine instance.
• Use SendGrid in Java code running on a Compute Engine instance.
• Use SendGrid in Node.js code running on a Compute Engine instance.

Costs

This tutorial uses billable components of Cloud Platform including Google Compute Engine.

New Cloud Platform users might be eligible for a free trial.

Before you begin

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Select or create a Google Cloud Platform project.

   Note: If you don't plan to keep the resources you create in this procedure, create a new project instead of selecting an existing project. After you finish following these steps, you can delete the project, removing all resources associated with the project.

   Go to the Manage resources page

3. Projeniz için faturalandırmanın etkinleştirildiğinden emin olun.

   Faturalandırmayı etkinleştirmeyi öğren

4. In the GCP Console, go to the VM Instances page.

   Go to the VM Instances page

5. Click Create instance.
6. Set Name to sendgrid-tutorial.
7. In the Boot disk section, click Change to begin configuring your boot disk.

8. On the OS images tab, choose a Debian or CentOS image.

9. Click Select.
10. Click Create to create the instance.
11. Use the GCP Marketplace to sign up for the SendGrid Email service. Make a note of your SendGrid SMTP account credentials, which include username, password, and hostname. Your SMTP username and password are the same as what you used to sign up for the service. The SendGrid hostname is smtp.sendgrid.net.
12. Create an API key:
    1. Sign in to Sendgrid and go to Settings > API Keys.
    2. Create an API key.
    3. Select the permissions for the key. At a minimum, the key will need Mail send permissions to send email.
    4. Click Save to create the key.
    5. SendGrid generates a new key. This is the only copy of the key so make sure to copy the key and save it for later.

Sending mail with Postfix on your instance

Follow these steps to connect to your sendgrid-tutorial instance and run SendGrid with Postfix.

Note: The SendGrid documentation provides a set of instructions for Postfix installation and setup. If you run into issues setting up Postfix with SendGrid, review the SendGrid Postfix instructions.

Connect to your sendgrid-tutorial instance using SSH

1. In the GCP Console, go to the VM Instances page.

   Go to the VM Instances page

2. In the list of virtual machine instances, click SSH in the row of the instance that you want to connect to.

Configuring SendGrid as an SMTP relay with Postfix

Run the following commands in your SSH terminal to use SendGrid as an SMTP relay with Postfix.

1. Become a superuser:

   sudo su -
   

2. Set a safe unmask:

   umask 077
   

3. Install the Postfix Mail Transport Agent:

   Debian

   apt-get update && apt-get install postfix libsasl2-modules -y

   CentOS

   yum install postfix cyrus-sasl-plain cyrus-sasl-md5 -y

   If prompted, select the Local Only configuration and accept the default domain name.

4. Modify the Postfix configuration options. Open /etc/postfix/main.cf for editing. For example, to use the nano text editor, enter the following command:

   nano /etc/postfix/main.cf
   

5. Update the file:

   1. Comment out the following lines:

      # default_transport = error
      # relay_transport = error
      

   2. Add the following lines to the end of the file:

      relayhost = [smtp.sendgrid.net]:2525
      smtp_tls_security_level = encrypt
      smtp_sasl_auth_enable = yes
      smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
      header_size_limit = 4096000
      smtp_sasl_security_options = noanonymous
      

      The above lines enforce SSL/TLS support and configure SMTP authentication for these requests. A simple access and security layer (SASL) module handles authentication in the Postfix configuration.

      Note: You must use port 2525 because port 25 and port 587 are not allowed on Compute Engine.

6. Save and close the file.

7. Generate the SASL password map using the API key you generated in the Before you begin section:

   echo [smtp.sendgrid.net]:2525 apikey:[YOUR_API_KEY] >> /etc/postfix/sasl_passwd
   

   where [YOUR_API_KEY] is the API key you generated.

8. Use the postmap utility to generate a .db file:

   postmap /etc/postfix/sasl_passwd
   

9. Verify that you have a .db file:

   ls -l /etc/postfix/sasl_passwd*
   

   -rw------- 1 root root    ...  /etc/postfix/sasl_passwd
   -rw------- 1 root root    ...  /etc/postfix/sasl_passwd.db
   

10. Remove the file containing your credentials, as it is no longer needed:

    rm /etc/postfix/sasl_passwd
    

11. Set the permissions on your .db file and verify that the other file was removed:

    chmod 600 /etc/postfix/sasl_passwd.db
    ls -la /etc/postfix/sasl_passwd.db
    

    -rw------- 1 root root    ...  /etc/postfix/sasl_passwd.db
    

12. Reload your configuration to load the modified parameters:

    Debian

    /etc/init.d/postfix restart
    

    CentOS

    postfix reload
    

13. Install the mailutils or mailx package:

    Debian

    apt-get install mailutils -y

    CentOS

    yum install mailx -y
    

14. Send a test email:

    echo '[MESSAGE]' | mail -s [SUBJECT] [[e-mail]]

    where:

    • [MESSAGE] is the body of the email.
    • [SUBJECT] is the subject of the email.
    • [[e-mail]] is the email address that you want to send a message to.

    Look in your system logs for a status line containing status and the successful server response code (250):

    Debian

    tail -n 5 /var/log/syslog
    

    CentOS

    tail -n 5 /var/log/maillog
    

Sending mail with Java on your instance

Connect to your sendgrid-tutorial instance using SSH

1. In the GCP Console, go to the VM Instances page.

   Go to the VM Instances page

2. In the list of virtual machine instances, click SSH in the row of the instance that you want to connect to.

Construct and send an email message

The following instructions use the SendGrid Java client library to construct and send an email message through SendGrid. You can view the full example on GitHub.

In your SSH terminal:

1. Become a superuser and set a safe umask:

   sudo su -
   umask 077
   

2. Install Java and Maven:

   apt-get update -y && apt-get install git-core openjdk-8-jdk maven -y
   

3. Clone the GitHub repo:

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git
   

4. Go to the main source code for the example:

   cd /root/java-docs-samples/compute/sendgrid/src/main/java/com/example/compute/sendgrid
   

5. Open SendEmailServelet.java for editing.

   • Replace YOUR-SENDGRID-API-KEY with the API key for your SendGrid account.

   • Replace YOUR-SENDGRID-FROM-EMAIL with the email address you you want to send mail from.

   • Replace DESTINATION-EMAIL with the email address you want to send mail to.

6. Go to the root directory of the sample code:

   cd /root/java-docs-samples/compute/sendgrid
   

7. Package the Java class:

   mvn clean package
   

8. Go to the new target directory:

   cd target
   

9. Set permissions to allow you to execute the jar file:

   chmod +x compute-sendgrid-1.0-SNAPSHOT-jar-with-dependencies.jar
   

10. Run the alternative Java version selector:

    update-alternatives --config java
    

    Select the java-8-openjdk-amd64 option.

11. Execute the Java file:

    java -jar compute-sendgrid-1.0-SNAPSHOT-jar-with-dependencies.jar
    

Sending mail with Node.js on your instance

To run this sample, you must have Node.js version 7.6 or newer installed on the VM instance.

Connect to your sendgrid-tutorial instance using SSH

1. In the GCP Console, go to the VM Instances page.

   Go to the VM Instances page

2. In the list of virtual machine instances, click SSH in the row of the instance that you want to connect to.

Construct and send an email message

In your SSH terminal:

1. Become a superuser and set a safe umask:

   sudo su -
   umask 077
   

2. Update your package repositories:

   Debian

   apt-get update
   

   CentOS

   yum update -y
   

3. Install Node.js dependencies:

   Debian

   apt-get install git-core curl build-essential openssl libssl-dev -y
   

   CentOS

   yum install git-core curl openssl openssl-devel -y
   yum groupinstall "Development Tools" -y
   

4. Install Node.js. The installation will also install npm by default:

   Debian

   curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
   sudo apt-get install -y nodejs
   

   CentOS

   curl --silent --location https://rpm.nodesource.com/setup_6.x | bash -
   

   Then, install Node.js:

   yum -y install nodejs
   

5. Install the SendGrid Node.js client:

   npm install sendgrid
   

6. Clone the sample repository:

   git clone https://github.com/googleapis/nodejs-compute.git
   

7. Go to the directory that contains the SendGrid sample:

   cd nodejs-compute/samples
   

8. Copy the sendgrid.js file:

   cp sendgrid.js sendmail.js
   

9. Open sendmail.js for editing.

   • Replace <your-sendgrid-api-key> with the API key for your SendGrid account.

   • Replace [e-mail] with the email address that you want to send mail from.

   • Replace [e-mail] with the email address that you want to send mail to.

   View on GitHub

   // This sample is based off of:
   // https://github.com/sendgrid/sendgrid-nodejs/tree/master/packages/mail
   const sendgrid = require('@sendgrid/mail');
   sendgrid.setApiKey(process.env.SENDGRID_API_KEY || '<your-sendgrid-api-key>');
   
   async function sendgridExample() {
     await sendgrid.send({
       to: '[e-mail]',
       from: '[e-mail]',
       subject: 'Sendgrid test email from Node.js on Google Cloud Platform',
       text:
         'Well hello! This is a Sendgrid test email from Node.js on Google Cloud Platform.',
     });
   }
   sendgridExample();

10. Execute the program to send an email message through SendGrid:

    node sendmail.js
    

Cleaning up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this tutorial:

Delete the project

The easiest way to eliminate billing is to delete the project that you created for the tutorial.

To delete the project:

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for this tutorial, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

If you plan to explore multiple tutorials and quickstarts, reusing projects can help you avoid exceeding project quota limits.

1. In the GCP Console, go to the Projects page.

   Go to the Projects page

2. In the project list, select the project you want to delete and click Delete .
3. In the dialog, type the project ID, and then click Shut down to delete the project.

Delete your Compute Engine instance

To delete a Compute Engine instance:

1. In the GCP Console, go to the VM Instances page.

   Go to the VM Instances page

2. Click the checkbox for your sendgrid-tutorial instance.
3. Click Delete to delete the instance.

What's next

Try out other Google Cloud Platform features for yourself. Have a look at our tutorials.