Added SendGrid output binding for sending emails

[benc-uk]

Description

Added an output binding for SendGrid
This sends simple HTML emails using the SendGrid API.

Example component

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: sendgrid
spec:
  type: bindings.twilio.sendgrid
  metadata:
  - name: emailFrom
    value: "testapp@dapr.io" # optional 
  - name: emailTo
    value: "dave@dapr.io" # optional 
  - name: subject
    value: "Hello!" # optional 
  - name: apiKey
    value: "CHANGEME" # required, this is your SendGrid key

The data field in the binding request is used as email body
You can specify any of the metadata properties on the request too (e.g. emailFrom, emailTo, subject)

Example payload

{
  "metadata": {
    "emailTo": "changeme@example.net",
    "subject": "An email from Dapr SendGrid binding"
  }, 
  "data": "<h1>Testing Dapr Bindings</h1>This is a test.<br>Bye!"
}

Test / demo app is here https://github.com/benc-uk/dapr-sendgrid-test

TODO: Add docs :)

Issue reference

Fixes #314

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation / Created issue in the https://github.com/dapr/docs/ repo: dapr/docs#[issue number] PR: Adding docs for SendGrid docs#535

[yaron2]

@jjcollinge do you mind reviewing this?

[jjcollinge]

@yaron2 yh np - will do tomorrow

[jjcollinge]

few comments

[jjcollinge]

LGTM - just need to decide on whether this lives under /bindings/twilio/sendgrid/sendgrid.go or just /bindings/sendgrid/sendgrid.go - I'll leave that to @yaron2

[yaron2]

I suggest the following:

/twilio/sms.go
/twilio/sendgrid.go

[benc-uk]

Moved the sms and sendgrid bindings into a twilio folder
Changed the component registration to bindings.twilio.sendgrid

The registration in daprd main.go now looks like

import(
	"github.com/dapr/components-contrib/bindings/twilio/sms"
	"github.com/dapr/components-contrib/bindings/twilio/sendgrid"
)

... ... ...

bindings_loader.NewOutput("twilio.sms", func() bindings.OutputBinding {
  return sms.NewSMS(logContrib)
}),
bindings_loader.NewOutput("twilio.sendgrid", func() bindings.OutputBinding {
  return sendgrid.NewSendGrid(logContrib)
})

Tested and working

[jjcollinge]

Moved the sms and sendgrid bindings into a twilio folder
Changed the component registration to bindings.twilio.sendgrid

The registration in daprd main.go now looks like

import(
	"github.com/dapr/components-contrib/bindings/twilio/sms"
	"github.com/dapr/components-contrib/bindings/twilio/sendgrid"
)

... ... ...

bindings_loader.NewOutput("twilio.sms", func() bindings.OutputBinding {
  return sms.NewSMS(logContrib)
}),
bindings_loader.NewOutput("twilio.sendgrid", func() bindings.OutputBinding {
  return sendgrid.NewSendGrid(logContrib)
})

Tested and working

Cool, thanks

[amanbha]

Please open a doc issue for this as well.

[benc-uk]

Just checking do you want me to set up a PR with some extra docs, or just an issue to discuss it?

[amanbha]

Doc issue to start with. PR would be great!

[benc-uk]

@amanbha Hi, I've created a PR for the docs. Let me know if you need an issue to track it too dapr/docs#535

[amanbha]

Great @benc-uk Thanks. I will merge it shortly, please make the corresponding changes in dapr runtime as well.

[yaron2]

Is sendgrid.go still under /sendgrid? It should move under /twilio/sendgrid.go

[yaron2]

And /twilio/sms.go

[benc-uk]

@yaron2 I moved them around #308 (comment)

[yaron2]

Ahh.. just to be clear I'm not hallucinating :)

Is it under /twilio/sendgrid.go? Or /twilio/sendgrid/sendgrid.go? It should be the former

[benc-uk]

twilio/sms/sms.go
and
twilio/sendgrid/sendgrid.go

This is the convention used by all the other directories that have multiple bindings. e.g. azure, aws, gcp

Otherwise we have two differently named packages in the same directory, which feels wrong

[yaron2]

LGTM