From Monolith to Microservices with Cassandra, gRPC, and Falcor (from Cassandra Summit 2016)
2 likes886 views
The document discusses transitioning from a modular monolith to microservices using technologies such as Cassandra, gRPC, and Falcor. It outlines the process of defining service contracts with protocol buffers, creating a standalone web tier, and utilizing Falcor for data fetching in a microservices architecture. The advantages of using microservices include easier scaling and maintenance of individual components, although challenges such as data ownership and integrating multiple services must be addressed.
![With Falcor you think of
your data as a graph.
Clients can request one or
more paths in the graph.
GET: /model.json
videosById['12345'][
'name', 'description',
'addedDate'
]
videosById['12345']
.author[
'firstName', 'lastName',
'email'
]
CAT BURRITO
By:
Luke Tillman](https://image.slidesharecdn.com/frommonolithtomicroserviceswithcassandragrpcandfalcor-160915172937/85/From-Monolith-to-Microservices-with-Cassandra-gRPC-and-Falcor-from-Cassandra-Summit-2016-15-320.jpg)
![19
{
"videosById": {
"12345": {
"name": "Burrito Cat",
"description": "A cat ...",
"addedDate": "2016-06-29",
"author": {
"$type": "ref",
"value": [ "usersById", "99" ]
}
}
}
}
The Falcor Router on the
server matches your paths
against a list of routes.
Each route has a handler
that can then call the
appropriate service.](https://image.slidesharecdn.com/frommonolithtomicroserviceswithcassandragrpcandfalcor-160915172937/85/From-Monolith-to-Microservices-with-Cassandra-gRPC-and-Falcor-from-Cassandra-Summit-2016-17-320.jpg)
![19
{
"videosById": {
"12345": {
"name": "Burrito Cat",
"description": "A cat ...",
"addedDate": "2016-06-29",
"author": {
"$type": "ref",
"value": [ "usersById", "99" ]
}
}
}
}
The Falcor Router on the
server matches your paths
against a list of routes.
Each route has a handler
that can then call the
appropriate service.](https://image.slidesharecdn.com/frommonolithtomicroserviceswithcassandragrpcandfalcor-160915172937/85/From-Monolith-to-Microservices-with-Cassandra-gRPC-and-Falcor-from-Cassandra-Summit-2016-18-320.jpg)
![22
Route handlers return data
in JSON Graph format
which can reference other
parts of the graph. The
Router automatically
follows references.
"author": {
"$type": "ref",
"value": [ "usersById", "99" ]
}
{
"usersById": {
"99": {
"firstName": "Luke",
"lastName": "Tillman",
"email": "luke@luketillman.com",
}
}
}](https://image.slidesharecdn.com/frommonolithtomicroserviceswithcassandragrpcandfalcor-160915172937/85/From-Monolith-to-Microservices-with-Cassandra-gRPC-and-Falcor-from-Cassandra-Summit-2016-19-320.jpg)
From Monolith to Microservices with Cassandra, gRPC, and Falcor (from Cassandra Summit 2016)
- 1. From Monolith to Microservices with Cassandra, gRPC, and Falcor Luke Tillman, Technical Evangelist at DataStax
- 2. 2 Luke, Technical Evangelist Currently: Cassandra .NET Node.js Previously: Web Applications RDBMS
- 3. A reference application for users looking to learn how to use Cassandra and DataStax Enterprise with their programming language of choice.
- 4. 4 KillrVideo was a modular monolith written entirely in C# using events for service collaboration. The modular monolith is a SOA where all services are in one programming language and can be run in-process together. But it can be difficult to stay disciplined and not blur service boundaries. omments Search Video Catalog
- 5. 8 Mixed technology stacks are a reality for more than just reference applications. How do we go from a modular monolith in a single programming language to “your programming language of choice”?
- 6. 1 Define our service contracts in a common format that can be consumed in multiple programming languages.
- 7. 10 The ability to generate client and server (stub) code was a requirement. There are a lot of choices when it comes to selecting an Interface Definition Language, including some other Apache projects like Avro and Thrift.
- 8. 11 Define your services using Protocol Buffers as the IDL. service RatingsService { rpc RateVideo(RateVideoRequest) returns (RateVideoResponse); } message RateVideoRequest { killrvideo.common.Uuid video_id = 1; killrvideo.common.Uuid user_id = 2; int32 rating = 3; } message RateVideoResponse { }
- 9. 12 Pros: • Generate client/server code in 9 languages • Built-in HTTP/2 transport • Protocol Buffers as the wire format • Comes from Google Cons: • Comes from Google READER 2005-2013
- 10. 2 Create a standalone web tier that can be reused by service implementations in multiple programming languages.
- 11. 14 Wanted a client web app that runs in a browser and works on multiple devices. The number of frontend JavaScript frameworks out there is mind numbing, but we eventually settled on a setup that makes heavy use of React and Redux.
- 12. 15 How should the client fetch data from the gRPC microservices on the backend?
- 13. 15 How should the client fetch data from the gRPC microservices on the backend? In the browser, we have a JavaScript library for fetching data. On the web server, we have the Falcor Router component that acts an API Gateway to the microservices.
- 14. Falcor More than just an awesome 80’s Luck Dragon.TM
- 15. With Falcor you think of your data as a graph. Clients can request one or more paths in the graph. GET: /model.json videosById['12345'][ 'name', 'description', 'addedDate' ] videosById['12345'] .author[ 'firstName', 'lastName', 'email' ] CAT BURRITO By: Luke Tillman
- 16. 19 The Falcor Router on the server matches your paths against a list of routes. Each route has a handler that can then call the appropriate service.
- 17. 19 { "videosById": { "12345": { "name": "Burrito Cat", "description": "A cat ...", "addedDate": "2016-06-29", "author": { "$type": "ref", "value": [ "usersById", "99" ] } } } } The Falcor Router on the server matches your paths against a list of routes. Each route has a handler that can then call the appropriate service.
- 18. 19 { "videosById": { "12345": { "name": "Burrito Cat", "description": "A cat ...", "addedDate": "2016-06-29", "author": { "$type": "ref", "value": [ "usersById", "99" ] } } } } The Falcor Router on the server matches your paths against a list of routes. Each route has a handler that can then call the appropriate service.
- 19. 22 Route handlers return data in JSON Graph format which can reference other parts of the graph. The Router automatically follows references. "author": { "$type": "ref", "value": [ "usersById", "99" ] } { "usersById": { "99": { "firstName": "Luke", "lastName": "Tillman", "email": "luke@luketillman.com", } } }
- 20. Can this architecture and these technologies help us with some of the challenges users have with Cassandra?
- 21. 24 Users coming from a RDBMS background are often frustrated by the lack of JOIN support in CQL. SELECT v.name, v.description, v.addedDate, u.firstName, u.lastName, u.email FROM videos v JOIN users u ON v.userId = u.userId WHERE v.videoId = 12345; CAT BURRITO By: Luke Tillman
- 22. 25 In a microservices architecture, data that we might have previously used a JOIN to retrieve is probably owned by different services now. Using references to other parts of the graph in Falcor makes stitching together data from multiple microservices easy.
- 23. 26 Using denormalization is a key part of successful Cassandra data modeling, but maintaining data integrity can seem daunting to new users. users users_by_email videos_by_date videos videos_by_user videos_by_tag
- 24. 27 The concept of data ownership in microservices makes the surface area of impacting operations much smaller. Having service APIs and events defined in an IDL like Protocol Buffers in gRPC makes it easy to get an immediate conceptual overview of what operations could impact denormalized data.
- 25. 28 Sizing a cluster, stress testing, and tuning for optimum performance is hard with Cassandra.
- 26. 29 With a microservices architecture, we ideally have different clusters backing different services. It's a lot easier to size, test, and tune a cluster for one service's workload than it is to tune a cluster for multiple services' workloads.