Kinesis Feed
Venuenext’s ordering system (named “Stadium”) publishes messages as orders’ states change. We can integrate those messages to clients’ systems.
How?
A lambda, hosted on VN’s AWS account, consumes the messages published by our ordering system. It can publish those messages to a kinesis stream (in the client’s account). Clients may hook up as many lambdas as they’d like to the stream in their own account.
Requirements
Venuenext
A kinesis stream for the ecosystem/env combination (e.g. mars-dev or levis-prd). A purpose-built lambda whose only responsibility is to publish to the client-hosted kinesis stream.
Client
A client-hosted lambda to consume from a kinesis stream in its own account.
Identity Management / Permissions
Clients must create the following:
- A kinesis stream.
- A consumer lambda bound to that stream, with whatever business logic they want.
- An IAM role or user, used by that lambda to read from the stream and give access to any other AWS resources it needs to acomplish its job. (e.g. S3 permission if the lambda is writing files to S3.)
- A “writer role”, which VN’s lambda will assume, so it can publish across AWS accounts, to the client-hosted kinesis stream. The writer role will grant
sts:AssumeRoleon the ARN of VN’s lambda.
Sample
{
"_id": "01egndytjh3xmmt154hxa6dz4m",
"_v": 1,
"o": "cubs",
"u": "1d1c41ee-a875-43dd-ad9c-4375256190de",
"s": "stadium",
"e": "order.state.change",
"p": {
"uuid": "b120fdbf-9b4e-44a8-99fd-4e21e3709c1f",
"venue_uuid": "e13b6c22-fdcf-4446-ba25-c240bc9bc40b",
"confirmation_number": "1234",
"state": "completion_pending",
"created_at": "2020-08-26T01:02:46Z",
"total": 7500,
"tax": 250,
"discount": "0",
"tip": 1250,
"device_uuid": "817c505d-d620-467b-b8a7-77ba9cd2fd30",
"revenue_center_name": "Suite 101",
"revenue_center_external_ref_id": "external-suite-101",
"revenue_center_uuid": "c30550a3-4f87-4a7d-8fd9-22afc2bdbbdb",
"menu_name": "Day of Event",
"menu_external_ref_id": "external-day-of-event",
"service_type": "POS",
"employee_name": null,
"employee_id": null,
"transaction_history": [{
"state": "authorized",
"time": "2020-08-26T01:02:47Z"
}],
"state_history": [{
"state": "tabbed",
"time": "2020-08-26T01:02:46Z"
}, {
"state": "processing",
"time": "2020-08-26T02:28:12Z"
}, {
"state": "completion_pending",
"time": "2020-08-26T02:28:13Z"
}],
"line_items": [{
"uuid": "6d268953-85c8-4db4-8091-33676e890c6f",
"name": "Sausage Sampler",
"price": 1000,
"sku": "5001",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": [{"discount_amount_in_cents": 0, "uuid": "8e8c197e-9b2b-4f40-a528-ce28f51404d7"}]
}, {
"uuid": "8aed311c-3c2d-46d8-9d63-c6d218491c1d",
"name": "Sausage Sampler",
"price": 1000,
"sku": "5001",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": []
}, {
"uuid": "038418fc-59b8-4b91-b8f7-b5d71ef2bbe1",
"name": "Sausage Sampler",
"price": 1000,
"sku": "5001",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": []
}, {
"uuid": "a4b862dc-bb73-4ae0-a805-5ddd25e6d7a7",
"name": "Sausage Sampler",
"price": 1000,
"sku": "5001",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": []
}, {
"uuid": "d888d272-2260-4761-8809-5a7ab92a1ec1",
"name": "Sausage Sampler",
"price": 1000,
"sku": "5001",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": []
}, {
"uuid": "887c26fd-0669-4d78-9319-ab46dbf3b86d",
"name": "Service Charge",
"price": 1000,
"sku": "servicechargebeeatch",
"created_at": "2020-08-26T01:02:46Z",
"refunded_at": null,
"removed_at": null,
"modified_line_item_uuid": null,
"promotions": []
}]
}
}
Data Types
{
"_id": standard ULID string
"_v": short integer
"o": 256 character string
"u": 36 character UUID
"s": short string, currently always “stadium”
"e": 256 character string
"p": {
"uuid": 36 character UUID string
"state": 256 character string
"created_at": 256 character date string
"total": 16-bit integer total in cents
"tax": 16-bit integer tax in cents
"discount": 256 character string discount amount
"tip": 16-bit integer tax in cents
"device_uuid": 36 character UUID string
"revenue_center_name": 256 character string
"revenue_center_external_ref_id": 256 character string
"menu_name": 256 character string
"menu_external_ref_id": 256 character string
"service_type": short string
"employee_name": 256 character string
"employee_id": 256 character string
"transaction_history": [{
"state": 256 character string
"time": 256 character date string
}],
"state_history": [{
"state": 256 character string
"time": 256 character date string
}],
"line_items": [{
"uuid": 36 character UUID string
"name": 256 character string
"price": 16-bit integer price in cents
"sku": 256 character string
"created_at": 256 character date string
"refunded_at": 256 character date string
"removed_at": 256 character date string
"modified_line_item_uuid": 36 character UUID string
}]
}
}
Conflict Resolution
As outlined above, each payload contains a state history array (of objects). There are timestamps included with each state transition. If that array contains the same elements AND the most recent timestamps are the same, then it can be presumed that the order hasn’t had a state change.
Another way to do this “quickly” if one wanted a “marker” would be to hash a sorted (by date) copy of that array as a string. An incoming state change with the same transition hash would be a duplicate.