restmail -- sendmail for email rest APIs

restmail is a sendmail-compatible CLI using gmail & outlook rest APIs. It can be used for email automation, notifications and with git send-mail for sharing patches.

restmail requires only minimal authorization scope to send mail. No access to reading or deleting mail is needed.

Install

# install to ~/go/bin ($GOPATH)
go install github.com/tonymet/restmail/cmd/restmail@latest

Initial Provider Setup (gmail or outlook)

Initial setup is done once / provider. This configures oauth2 clientID & Secret

FROM=your.name@gmail.com
CLIENT_ID=xxxxxx
CLIENT_SECRET=yyyy
restmail -configClient -provider gmail -clientId "${CLIENT_ID}" \ 
   -clientSecret "${CLIENT_SECRET}" -f "${FROM}"

Authorization Setup

Once provider config is set up above, you need to do the oauth flow through a web browser. Setup is only done once or if the tokens are invalidated.

FROM=your.name@gmail.com
restmail -authorize -provider gmail -f "${FROM}"

When this is complete, your auth-token & refresh-token are saved and refreshed automatically.

Sending Messages

FROM=your.name@gmail.com
TO=friend@gmail.com
CC=billy@gmail.com
echo "subject: test subject\n\ntest message" | restmail -f "${FROM}" -provider gmail "${TO}" cc:"${CC}"

Git send-mail configuration

[sendemail]
        smtpServer = /home/USERNAME/go/bin/restmail
        smtpServerOption = -f=your.name@gmail.com 
        smtpServerOption = -provider 
        smtpServerOption = gmail

Running Via Container & Cloud Storage

restmail can be run via container with Google Cloud storage

Build

 docker build . -t containermail 

Env & Permissions

GCS_PREFIX=test/restmail
GCS_BUCKET=YOUR_BUCKET

GCS Perms will load using APP Default Credentials. Be sure to authorize gcloud auth login before proceeding. The user will need role/Storage Object User for saving & loading the tokens

Setup OAuth Config & Token

re-run the OAuth Config with -storage gcs. This will save config to your bucket

FROM=your.name@gmail.com
CLIENT_ID=xxxxxx
CLIENT_SECRET=yyyy
restmail -configClient -storage gcs -provider gmail -clientId "${CLIENT_ID}" \ 
   -clientSecret "${CLIENT_SECRET}" -f "${FROM}"

re-run the auth step to save the token. this only needs doing once (refresh token will save)

FROM=your.name@gmail.com
restmail -authorize -storage gcs -provider gmail -f "${FROM}"

Launch the Container

You can run the container on cloud run with args -provider $PROVIDER -f $FROM -m "$MESSAGE" $TO_ADDR

Related Projects

• sendgmail & gmail-oauth-tools send mail via sendmail-compatible CLI to google via SMTP