SendGrid - NoMethodError (undefined method `[]' for nil:NilClass)

KCAS · November 11, 2023, 10:24pm

Hello,

Have started to use the sendgrid webhook with verification key. Now are getting a lot of these errors. Had sent out a bulk invite with sendgrid.

app/controllers/webhooks_controller.rb:29:in `block in sendgrid'
app/controllers/webhooks_controller.rb:24:in `each'
app/controllers/webhooks_controller.rb:24:in `sendgrid'
actionpack (7.0.7) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (7.0.7) lib/abstract_controller/base.rb:215:in `process_action'
actionpack (7.0.7) lib/action_controller/metal/rendering.rb:165:in `process_action'
actionpack (7.0.7) lib/abstract_controller/callbacks.rb:234:in `block in process_action'
activesupport (7.0.7) lib/active_support/callbacks.rb:107:in `run_callbacks'
actionpack (7.0.7) lib/abstract_controller/callbacks.rb:233:in `process_action'
actionpack (7.0.7) lib/action_controller/metal/rescue.rb:23:in `process_action'
actionpack (7.0.7) lib/action_controller/metal/instrumentation.rb:67:in `block in process_action'
activesupport (7.0.7) lib/active_support/notifications.rb:206:in `block in instrument'
activesupport (7.0.7) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (7.0.7) lib/active_support/notifications.rb:206:in `instrument'
actionpack (7.0.7) lib/action_controller/metal/instrumentation.rb:66:in `process_action'
actionpack (7.0.7) lib/action_controller/metal/params_wrapper.rb:259:in `process_action'
activerecord (7.0.7) lib/active_record/railties/controller_runtime.rb:27:in `process_action'
actionpack (7.0.7) lib/abstract_controller/base.rb:151:in `process'
actionview (7.0.7) lib/action_view/rendering.rb:39:in `process'
rack-mini-profiler (3.1.1) lib/mini_profiler/profiling_methods.rb:85:in `block in profile_method'
actionpack (7.0.7) lib/action_controller/metal.rb:188:in `dispatch'
actionpack (7.0.7) lib/action_controller/metal.rb:251:in `dispatch'
actionpack (7.0.7) lib/action_dispatch/routing/route_set.rb:49:in `dispatch'
actionpack (7.0.7) lib/action_dispatch/routing/route_set.rb:32:in `serve'
actionpack (7.0.7) lib/action_dispatch/journey/router.rb:50:in `block in serve'
actionpack (7.0.7) lib/action_dispatch/journey/router.rb:32:in `each'
actionpack (7.0.7) lib/action_dispatch/journey/router.rb:32:in `serve'
actionpack (7.0.7) lib/action_dispatch/routing/route_set.rb:852:in `call'
lib/middleware/omniauth_bypass_middleware.rb:64:in `call'
rack (2.2.8) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.2.8) lib/rack/conditional_get.rb:40:in `call'
rack (2.2.8) lib/rack/head.rb:12:in `call'
actionpack (7.0.7) lib/action_dispatch/http/permissions_policy.rb:38:in `call'
lib/content_security_policy/middleware.rb:12:in `call'
lib/middleware/anonymous_cache.rb:389:in `call'
lib/middleware/gtm_script_nonce_injector.rb:10:in `call'
rack (2.2.8) lib/rack/session/abstract/id.rb:266:in `context'
rack (2.2.8) lib/rack/session/abstract/id.rb:260:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/cookies.rb:704:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
activesupport (7.0.7) lib/active_support/callbacks.rb:99:in `run_callbacks'
actionpack (7.0.7) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/debug_exceptions.rb:28:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/show_exceptions.rb:29:in `call'
logster (2.13.1) lib/logster/middleware/reporter.rb:40:in `call'
railties (7.0.7) lib/rails/rack/logger.rb:40:in `call_app'
railties (7.0.7) lib/rails/rack/logger.rb:27:in `call'
config/initializers/100-quiet_logger.rb:20:in `call'
config/initializers/100-silence_logger.rb:29:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/remote_ip.rb:93:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/request_id.rb:26:in `call'
lib/middleware/enforce_hostname.rb:24:in `call'
rack (2.2.8) lib/rack/method_override.rb:24:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/executor.rb:14:in `call'
rack (2.2.8) lib/rack/sendfile.rb:110:in `call'
actionpack (7.0.7) lib/action_dispatch/middleware/host_authorization.rb:131:in `call'
rack-mini-profiler (3.1.1) lib/mini_profiler.rb:260:in `call'
message_bus (4.3.8) lib/message_bus/rack/middleware.rb:60:in `call'
lib/middleware/request_tracker.rb:233:in `call'
railties (7.0.7) lib/rails/engine.rb:530:in `call'
railties (7.0.7) lib/rails/railtie.rb:226:in `public_send'
railties (7.0.7) lib/rails/railtie.rb:226:in `method_missing'
rack (2.2.8) lib/rack/urlmap.rb:74:in `block in call
rack (2.2.8) lib/rack/urlmap.rb:58:in `each'
rack (2.2.8) lib/rack/urlmap.rb:58:in `call'
unicorn (6.1.0) lib/unicorn/http_server.rb:634:in `process_client'
unicorn (6.1.0) lib/unicorn/http_server.rb:739:in `worker_loop'
unicorn (6.1.0) lib/unicorn/http_server.rb:547:in `spawn_missing_workers'
unicorn (6.1.0) lib/unicorn/http_server.rb:143:in `start'
unicorn (6.1.0) bin/unicorn:128:in `<top (required)>'
vendor/bundle/ruby/3.2.0/bin/unicorn:25:in `load'
vendor/bundle/ruby/3.2.0/bin/unicorn:25:in `<main>'

ENV

|REQUEST_URI|/webhooks/sendgrid|
|REQUEST_METHOD|POST|
|HTTP_USER_AGENT|SendGrid Event API|

Seems to be the same as here, which was a fixed issue a while back: Sendgrid error: NoMethodError (undefined method `[]' for nil:NilClass) - #3 by Terrapop

pfaffman · November 12, 2023, 1:34pm

Are those generated for bounces from your list that are not discourse users?

KCAS · November 12, 2023, 3:59pm

Not sure about if they’re bounces, how could we check? It’s most likely around the time we did a bulk invite to non-discourse users.

selase · November 13, 2023, 11:21am

There might be something going on with the event payload being received from Sendgrid. It seems status isn’t being set on the bounce events as expected.

Assuming you got the backtrace from logster at <YOUR_SITE>/logs, the env tab should have the request details. Could you provide a sanitized copy of the payload from there?

KCAS · November 13, 2023, 12:35pm

There’s not a lot of info there, most of it i’ve put here.

For the full reference, i’ve put it below as requested

hostname	serverhostname
process_id	248749
application_version	a8d6dc4d3a5c3d937ff0bb162c93ec628428cda1
HTTP_HOST	forum.URL.co.uk
REQUEST_URI	/webhooks/sendgrid
REQUEST_METHOD	POST
HTTP_USER_AGENT	SendGrid Event API
HTTP_X_FORWARDED_FOR	IPADDRESS
HTTP_X_REAL_IP	IPADDRESS
time	Su 5:54 pm

selase · November 13, 2023, 1:23pm

KCAS:

For the full reference, i’ve put it below as requested

hostname serverhostname

process_id 248749

application_version a8d6dc4d3a5c3d937ff0bb162c93ec628428cda1

HTTP_HOST forum.URL.co.uk

REQUEST_URI /webhooks/sendgrid

REQUEST_METHOD POST

HTTP_USER_AGENT SendGrid Event API

HTTP_X_FORWARDED_FOR IPADDRESS

HTTP_X_REAL_IP IPADDRESS

time Su 5:54 pm

I am sorry, I should have been more specific. The request body has the clues needed. You should be able to find this after the time row. You may have to scroll up or expand panel to see this.

KCAS · November 13, 2023, 1:58pm

Hello,

There is no further information after the Time row, i’ve checked all of the 34 of the errors. Seems odd however it’s not included?

selase · November 14, 2023, 12:02pm

Yes, it’s odd. Could you retrieve the payload from the SendGrid dashboard instead?

Per the latest SendGrid webhooks docs, the current endpoint in Discourse should work without issues but the error points to an issue with the request payload so sample will be great.

cultiv · February 23, 2025, 8:48am

Did you ever figure this one out? I have the same error, on the same line of code:

github.com/discourse/discourse

app/controllers/webhooks_controller.rb

main


      
              "Received a Sendgrid webhook, but no verification key has been configured. This is unsafe behaviour and will be disallowed in the future.",
            )
          end
          
          events = params["_json"] || [params]
          events.each do |event|
            message_id = Email::MessageIdService.message_id_clean((event["smtp-id"] || ""))
            to_address = event["email"]
            error_code = event["status"]
            if event["event"] == "bounce"
              if error_code[Email::SMTP_STATUS_TRANSIENT_FAILURE]
                process_bounce(message_id, to_address, SiteSetting.soft_bounce_score, error_code)
              else
                process_bounce(message_id, to_address, SiteSetting.hard_bounce_score, error_code)
              end
            elsif event["event"] == "dropped"
              process_bounce(message_id, to_address, SiteSetting.hard_bounce_score, error_code)
            end
          end
          
          success

I am not familiar with Ruby but it looks like it can parse the json just fiine up until trrying to parse the error code, Email::SMTP_STATUS_TRANSIENT_FAILURE points to:

github.com/discourse/discourse

lib/email.rb

main


      
          # frozen_string_literal: true
          
          require "mail"
          
          module Email
            # See https://www.iana.org/assignments/smtp-enhanced-status-codes/smtp-enhanced-status-codes.xhtml#smtp-enhanced-status-codes-1
            SMTP_STATUS_SUCCESS = "2."
            SMTP_STATUS_TRANSIENT_FAILURE = "4."
            SMTP_STATUS_PERMANENT_FAILURE = "5."
          
            def self.is_valid?(email)
              return false unless String === email
              EmailAddressValidator.valid_value?(email)
            end
          
            def self.downcase(email)
              return email unless Email.is_valid?(email)
              email.downcase

I checked in Webhook.site what Sendgrid actually sends when I test the webhook and it looks like this for a bounce:

[
  {
    "email": "example@test.com",
    "timestamp": 1740136261,
    "smtp-id": "<14c5d75ce93.dfd.64b469@ismtpd-555>",
    "event": "bounce",
    "category": [
      "cat facts"
    ],
    "sg_event_id": "ovGQ2rRo8ytNezHPDq-7Ig==",
    "sg_message_id": "14c5d75ce93.dfd.64b469.filter0001.16648.5515E0B88.0",
    "reason": "500 unknown recipient",
    "status": "5.0.0"
  }
]

Seems like it should work!

cultiv · February 23, 2025, 9:02am

Aha… answering my own question here, the Webhook “Test integration” button lies to you…

Here is the actual payload if I actually send an email to a non-existing email address:

[
  {
    "bounce_classification": "Unclassified",
    "email": "noemail@this.does.not.exist.tld",
    "event": "bounce",
    "reason": "unable to get mx info: failed to get IPs from PTR record: lookup <nil>: unrecognized address",
    "sg_event_id": "Ym91bmNlLTQtNTA0ODUxOTUtZXVvMmlLeGRTYXlQRjRZRTQtLUk3QS0w",
    "sg_message_id": "euo2iKxdSayPF4YE4--I7A.recvd-5f54b5d587-pczjm-1-67BADEEA-6.0",
    "smtp-id": "<870b3a2a-160c-4fc8-bc9a-bd0d5b943b81@forum.umbraco.com>",
    "timestamp": 1740300320,
    "tls": 0,
    "type": "blocked"
  }
]

And there we have it: no status field.

This is when I purposely use a domain that does not exist, I feel like this should be handled, perhaps "type": "blocked" can be the indicator Discourse looks for.

As a different attempt I put some nonsense in front of outlook.com and that does give me a working payload:

[
  {
    "bounce_classification": "Invalid Address",
    "email": "oeihoiwehitwiohtriuweruiwerwierhwuerguiwerg@outlook.com",
    "event": "bounce",
    "ip": "149.72.1.78",
    "reason": "550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [HK3PEPF0000021E.apcprd03.prod.outlook.com 2025-02-23T08:54:35.950Z 08DD502499E1A0AA]",
    "sg_event_id": "Ym91bmNlLTAtNTA0ODUxOTUtQWJFZ2pVejZUUFd3MnJNTnJabDg4Zy0w",
    "sg_message_id": "AbEgjUz6TPWw2rMNrZl88g.recvd-786d47b7ff-tsp86-1-67BAE249-D.0",
    "smtp-id": "<d8dc253e-6e9a-4418-8478-60780eb4898c@forum.umbraco.com>",
    "status": "5.5.0",
    "timestamp": 1740300876,
    "tls": 1,
    "type": "bounce"
  }
]

cultiv · February 23, 2025, 9:28am

Made a PR!

github.com/discourse/discourse

Sendgrid webhook payload is different for unreachable hosts

main ← nul800sebastiaan:fix-sendgrid-webhook

opened 09:27AM - 23 Feb 25 UTC

nul800sebastiaan

+5 -1

As described in https://meta.discourse.org/t/sendgrid-nomethoderror-undefined-me…thod-for-nil-nilclass/285221/9?u=cultiv When an email bounced because the host does not exist (any more), the payload of the webhook Sendgrid sends does not include a `status` field, leading to an error: `NoMethodError (undefined method `[]' for nil)`. The payload is as follows: ```json [ { "bounce_classification": "Unclassified", "email": "noemail@this.does.not.exist.tld", "event": "bounce", "reason": "unable to get mx info: failed to get IPs from PTR record: lookup <nil>: unrecognized address", "sg_event_id": "Ym91bmNlLTQtNTA0ODUxOTUtZXVvMmlLeGRTYXlQRjRZRTQtLUk3QS0w", "sg_message_id": "euo2iKxdSayPF4YE4--I7A.recvd-5f54b5d587-pczjm-1-67BADEEA-6.0", "smtp-id": "<870b3a2a-160c-4fc8-bc9a-bd0d5b943b81@forum.umbraco.com>", "timestamp": 1740300320, "tls": 0, "type": "blocked" } ] ``` I figured `"type": "blocked"` is probably a good thing to test on and set the `error_code` for. I feel like this is probably an unrecoverable error, so I turned it into a `5.5.0` error, just like when an email on a valid domain bounces. Furthermore, before reading the `error_code`, I added a check for `nil`, just in case the variable has still not been set for some reason. Word of warning: this is my first time writing Ruby code, so please correct me if I am doing it wrong 😅

tgxworld · February 25, 2025, 5:17am

@cultiv Thank you for diving into the problem here and taking the time to submit a PR. I’ve used your PR as a base and merged a fix for the issue in FIX: No method error in `WebhooksController#sendgrid` (#31495) · discourse/discourse@209d289 · GitHub.

cultiv · February 25, 2025, 2:08pm

Fantastic, that was very helpful. Wouldn’t have been able to do all of that on my own

Thanks, I’ve updated and a manual test now does things correctly, error log is clean and I can see the email bounced in the mail log

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SendGrid - NoMethodError (undefined method `[]' for nil:NilClass)

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