Add ruby examples for triggers on lambda (address hasura#1740) (hasura#3007)

Author: grzegorz-wcislo

community/boilerplates/event-triggers/aws-lambda/README.md

@@ -7,12 +7,12 @@ These are organized in language-specific folders.
 **NOTE**
 Some of the language/platforms are work in progress. We welcome contributions for the WIP langauages. See issues and the following checklist:
 
-| Folder name | Use-case| Node.js(6) | Python | Java | Go | C#	
-|-------------|---------|:--------:|:------:|:----:|:---:|:---:	
-| echo | echo the trigger payload  | ✅ | ✅ | ❌ | ✅ | ❌ 	
-| mutation | insert related data on an insert event using graphql mutation | ✅ | ✅ | ❌ | ✅ | ❌ 	
-| push-notification | send push notification on database event | ❌ | ❌ | ❌ | ❌ | ❌	
-| etl | transform the trigger payload and update an algolia index | ❌ | ❌ | ❌ | ❌ | ❌	
+| Folder name | Use-case| Node.js(6) | Python | Java | Go | C# | Ruby
+|-------------|---------|:--------:|:------:|:----:|:---:|:---:|:---:
+| echo | echo the trigger payload  | ✅ | ✅ | ❌ | ✅ | ❌ | ✅
+| mutation | insert related data on an insert event using graphql mutation | ✅ | ✅ | ❌ | ✅ | ❌ | ✅
+| push-notification | send push notification on database event | ❌ | ❌ | ❌ | ❌ | ❌ | ❌
+| etl | transform the trigger payload and update an algolia index | ❌ | ❌ | ❌ | ❌ | ❌ | ❌
 
 
 

community/boilerplates/event-triggers/aws-lambda/ruby/echo/README.md

@@ -0,0 +1,37 @@
+# Setup tables
+
+1. Create table:
+
+```
+profile (
+  id INT PRIMARY KEY,
+  name TEXT
+)
+```
+
+# Setup AWS Lambda
+
+Create a lambda function in AWS. This will be our webhook.
+
+1. Create a function.
+1. Select Ruby 2.5 as the runtime.
+1. Select "Author from scratch".
+1. Select "handler" as the function name.
+1. Press "Create function".
+1. Add API gateway as a trigger (in this example you can use Open as the security option).
+1. Add an API to API gateway.
+1. Add the code in `lambda_function.rb` to the lambda function editor. The handler function of your lambda will be the lambda_handler.
+
+
+# Add the trigger in Hasura GraphQL
+
+1. In events tab, add a trigger
+1. Select all insert, update, delete operations for the trigger.
+1. Paste the API endpoint of your AWS lambda as the webhook.
+
+# Test your integration
+
+1. Create a record.
+1. Update a record.
+1. Delete a record.
+1. Check the logs (in the Events tab) to see what is going on.

community/boilerplates/event-triggers/aws-lambda/ruby/echo/lambda_function.rb

@@ -0,0 +1,38 @@
+require 'json'
+
+def lambda_handler(event:, context:)
+  body = JSON.parse(event['body'])
+  table_name = body['table']['name']
+  op = body['event']['op']
+  data = body['event']['data']
+
+  response = case op
+             when 'INSERT' then insert_message(data, table_name)
+             when 'UPDATE' then update_message(data, table_name)
+             when 'DELETE' then delete_message(data, table_name)
+             end
+
+  { statusCode: 200, body: response }
+rescue
+  { statusCode: 400, body: 'Cannot parse hasura event' }
+end
+
+def insert_message(data, table_name)
+  "New record #{new(data)} inserted into table #{table_name}"
+end
+
+def update_message(data, table_name)
+  "Record changed from #{old(data)} to #{new(data)} in table #{table_name}"
+end
+
+def delete_message(data, table_name)
+  "Record #{old(data)} was deleted from table #{table_name}"
+end
+
+def new(data)
+  JSON.generate(data['new'])
+end
+
+def old(data)
+  JSON.generate(data['old'])
+end

community/boilerplates/event-triggers/aws-lambda/ruby/mutation/README.md

@@ -0,0 +1,49 @@
+# Setup tables
+
+1. Create the table using the console:
+
+```
+Table name: notes
+
+Columns:
+id: Integer auto-increment
+note: Text
+
+Table name: note_revision
+
+Columns:
+id: Integer auto-increment
+note: Text
+note_id: Integer (foreign key to notes.id)
+update_at: Timestamp, default `now()`
+
+```
+
+# Setup AWS Lambda
+
+Create a lambda function in AWS. This will be our webhook.
+
+1. Create a function.
+1. Select Ruby 2.5 as the runtime.
+1. Select "Author from scratch".
+1. Select "handler" as the function name.
+1. Press "Create function".
+1. Add API gateway as a trigger (in this example you can use Open as the security option).
+1. Add an API to API gateway.
+1. Add the code in `lambda_function.rb` to the lambda function editor. The handler function of your lambda will be the lambda_handler.
+1. Add the following enviroment variables in your lambda config:
+   1. `ACCESS_KEY`: this is the access key you configured when you setup HGE (`HASURA_GRAPHQL_ADMIN_SECRET` env variable).
+   1. `HGE_ENDPOINT`: the URL on which you HGE instance is running.
+
+# Add the trigger in Hasura GraphQL
+
+1. In events tab, add a trigger
+1. Select the "notes" table and the update trigger.
+1. Paste the API endpoint of your AWS lambda as the webhook.
+
+# Test your integration
+
+1. Create a note.
+1. Change the contents of the note.
+1. Select all note revisions, previous note value should be visible.
+1. Check the logs (in the Events tab) to see what is going on.

community/boilerplates/event-triggers/aws-lambda/ruby/mutation/lambda_function.rb

@@ -0,0 +1,44 @@
+require 'json'
+require 'net/http'
+
+def lambda_handler(event:, context:)
+  access_key = ENV['ACCESS_KEY']
+  hge_endpoint = ENV['HGE_ENDPOINT']
+  query = <<~QUERY
+    mutation updateNoteRevision ($noteId: Int!, $data: String!) {
+      insert_note_revision (objects: [
+        {
+          note_id: $noteId,
+          note: $data
+        }
+      ]) {
+        affected_rows
+      }
+    }
+  QUERY
+
+  note_id = JSON.parse(event['body'])['event']['data']['old']['id']
+  data = JSON.parse(event['body'])['event']['data']['old']['note']
+
+  uri = URI.parse(hge_endpoint + '/v1/graphql')
+  use_ssl = (uri.scheme == 'https')
+
+  res = Net::HTTP.start(uri.host, uri.port, use_ssl: use_ssl) do |http|
+    req = Net::HTTP::Post.new(uri)
+    req['Content-Type'] = 'application/json'
+    req['x-hasura-access-key'] = access_key
+    req.body = JSON.generate(
+      query: query,
+      variables: { noteId: note_id, data: data }
+    )
+    http.request(req)
+  end
+
+  if errors = JSON.parse(res.body)['errors']
+    return { statusCode: 400, body: JSON.generate(errors) }
+  end
+
+  { statusCode: 200, body: 'success' }
+rescue
+  { statusCode: 400, body: 'cannot parse hasura event' }
+end