How does it work, exactly?
Number6 is a serverless app hosted on AWS, built and deployed using their Serverless Application Model framework. It’s based on lambda functions written in Kotlin using a hexagonal architecture (“ports and adaptors”) and the Dagger DI framework. Here’s a picture of it in action:
These are the resources in the diagram:
| Name | Type | Purpose |
|---|---|---|
| SlackComprehensions | DynamoDb | Table holding a row for each channel and date that Number6 analyses |
| SlackReaderFunction | Lambda | Calls the Slack API to retrieve all the messages for each public channel each day (or for a specific date in testing), puts them onto the SlackChannelMessagesTopic |
| SlackChannelMessagesTopic | SNS | topic that notifies listeners of all the messages on a channel for a day |
| MessageSentimentFunction | Lambda | listens to SlackChannelMessagesTopic, sends all the Slack messages to Amazon Comprehend for sentiment analysis, writes a summary to the SlackComprehensions table |
| MessageEntityFunction | Lambda | listens to SlackChannelMessagesTopic, sends all the Slack messages to Amazon Comprehend for entity analysis, writes a summary to the SlackComprehensions table |
| MessageKeyPhrasesFunction | Lambda | listens to SlackChannelMessagesTopic, sends all the Slack messages to Amazon Comprehend for key phrases analysis, writes a summary to the SlackComprehensions table |
| ProcessComprehensionsStream | Lambda | triggered by updates to the SlackComprehensions table, when the sentiment, entity and key phrases analysis for a channel have been updated in the database it posts the details to Slack |
Not shown is AWS Secrets Manager which holds the Slack access token needed to use the Slack API.
Number6 is created in a single CloudFormation stack containing all its resources with the possible exception of the Slack token in AWS Secrets Manager, depending on how you choose to deploy it.
The DynamoDB table is configured for on-demand capacity with no backup schedule. This is the cheapest configuration, if backups and/or provisioned capacity are important to you you’ll need to update the table configuration manually or deploy a non-SAR version.