In Google cloud function, have FileNotFoundError: [Errno 2] No such file or directory: '/usr/sbin/sendmail': '/usr/sbin/sendmail'

Question

I want to send email with attachments using a python script in Google Cloud Function Here is the code:

def send_mail(text, from_user, to_user, subject):
    print ("SENDING EMAIL....")
    msg = MIMEMultipart()
    msg['From'] = from_user
    msg['To'] = ", ".join(to_user)
    msg['Subject'] = subject
    msg.attach(MIMEText(text, 'plain'))
    p = MIMEBase('application', 'octet-stream')
    attachment = open(join_path(OUTPUT_FILE_DIR, OUTPUT_FILENAME), "rb")
    p.add_header('Content-Disposition', "attachment; filename= %s"
                 % OUTPUT_FILENAME)
    p.set_payload(attachment.read())
    encoders.encode_base64(p)
    msg.attach(p)
    attachment.close()
    proc = Popen(['/usr/sbin/sendmail', '-t'], stdin=PIPE)
    proc.communicate(msg.as_string())
    return

And got this error: FileNotFoundError: [Errno 2] No such file or directory: '/usr/sbin/sendmail': '/usr/sbin/sendmail'

Is this proc legal in gcp? or Is there any replacement for it? Thank you so much

Answer 1

With Cloud Functions you don't control your execution runtime, and you can't assume that a binary exist or not (and if it exists, it can disappear anytime). It's serverless! You only deploy your code

If you want more control on the environment runtime, you can use Cloud Run, very similar to Cloud Functions but you have to define your container and install all the dependencies that you want.

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However, it won't work. The port 25 is blocked on Google cloud and you have to use external tools (sendgrid, twilio,...) to send emails.