"The dirty secret of the microservices movement is the heavy operational burden of service provisioning, discovery and interface specification. For many applications, e.g. those with logically grouped activities or that require single-tenant deployment, microservices are a “bridge too far.” In-place refactoring of monolithic applications with service-oriented architecture presents a 3rd-way between monoliths and microservices. OpenAPI provides the API specification and the supporting tooling ecosystem to define sensible service boundaries at the API-layer, substantially de-risking monolith refactors. We present a “war story”, targeted at software architects and developers, detailing the design and implementation considerations that allowed us to use OpenAPI to “break” our monolithic code-base into sensible services to support our life-sciences partners."

1. Breaking a Monolith
In-Place Refactoring with Service-Oriented Architecture
at a Life-Sciences Startup
Ryan M Harrison, PhD
Head of Engineering
BioBright

2. The Lab
2

3. 3
Image Metadata
Objective
Excitation
Emission
Label
Reagents
Protocols
Exp Metadata Analysis MetadataRaw Image
Collect all the things

4. 4
Business proposition
in development
DarwinSync DarwinSpeech DarwinTerminal

5. 5

6. 6
Courtesy of https://www.weave.works

7. 7
MicroservicesMonoliths

8. 8
Shiny things!
API Gateway Lambda

9. 9

10. 10
Self-reflection
- B2B / Enterprise
- Unconstrained problem
- Scaling needs?

11. 11
Self-reflection
- B2B / Enterprise ⇒ On prem?
- Unconstrained problem ⇒ Rapid iteration
- Scaling needs? ⇒ Slow / predictable

12. 12
Code: 2016
exports.lastActions = function(req, res) { // data query for lastActions, ember data model
console.log("req: ", req.query);
var user = req.query.user; // get user
var x1 = Math.floor(req.query.x[0]); // get start of time range
var x2 = Math.floor(req.query.x[1]); // end of time range
coknexions[req.lab]('data') // query from data table on users lab
.whereIn('source', user) // query source
.whereBetween("x",[x1, x2]) // query range
.orderBy('x', 'desc') // oldest to newest
.then(function(r){ // results in r
res.json({lastActions:r}); // send in form expected by ember
});
};

13. 13
Self-reflection
exports.lastActions = function(req, res) {
console.log("req: ", req.query);
var user = req.query.user;
var x1 = Math.floor(req.query.x[0]);
var x2 = Math.floor(req.query.x[1]);
coknexions[req.lab]('data')
.whereIn('source', user)
.whereBetween("x",[x1, x2])
.orderBy('x', 'desc')
.then(function(r){
res.json({lastActions:r});
});
};
No documentation

14. 14
Self-reflection
exports.lastActions = function(req, res) {
console.log("req: ", req.query);
var user = req.query.user;
var x1 = Math.floor(req.query.x[0]);
var x2 = Math.floor(req.query.x[1]);
coknexions[req.lab]('data')
.whereIn('source', user)
.whereBetween("x",[x1, x2])
.orderBy('x', 'desc')
.then(function(r){
res.json({lastActions:r});
});
};
Minimal logging

15. 15
Self-reflection
exports.lastActions = function(req, res) {
console.log("req: ", req.query);
var user = req.query.user;
var x1 = Math.floor(req.query.x[0]);
var x2 = Math.floor(req.query.x[1]);
coknexions[req.lab]('data')
.whereIn('source', user)
.whereBetween("x",[x1, x2])
.orderBy('x', 'desc')
.then(function(r){
res.json({lastActions:r});
});
};
No input specification
(or validation)
No output specification

16. 16
Self-reflection
exports.lastActions = function(req, res) {
console.log("req: ", req.query);
var user = req.query.user;
var x1 = Math.floor(req.query.x[0]);
var x2 = Math.floor(req.query.x[1]);
coknexions[req.lab]('data')
.whereIn('source', user)
.whereBetween("x",[x1, x2])
.orderBy('x', 'desc')
.then(function(r){
res.json({lastActions:r});
});
};
Inadequate interface to DB layer

17. 17
Problem
- B2B / Enterprise ⇒ On prem?
- Unconstrained problem ⇒ Rapid iteration
- Scaling needs? ⇒ Slow / predictable
- Engineering maturity ⇒
- Code quality ⇒

18. 18
Must be
this tall
to ride
(the hype)
2016
Not tall enough

19. 19
Must be
this tall
to ride
(the hype)
?
2016
Not tall enough

20. 20
Not tall enough
Dev portal
Monitoring
On demand infra scaling
Continuous Integration
Continuous Deployment

21. 21
Glide paths
API spec → API docs → Dev portal
Logging → Monitoring
Infra → On demand infra scaling
Testing → Continuous Integration
Deployment → Continuous Deployment

22. 22
3 B’s
Build it
Borrow it
Buy it

23. 23
Image Metadata
Objective
Excitation
Emission
Label
Reagents
Protocols
Exp Metadata Analysis MetadataRaw Image
Collect all the things

24. 24
API

25. 25
Raw Image Analysis MetadataExperiment MetadataImage Metadata
API APIAPIAPI
API

26. 26
API (Borrow)
/protocols/notes:
x-swagger-router-controller: protocols
post:
operationId: post_note
security:
- JWT: [write:protocols]
parameters:
...
schema:
$ref: '#/definitions/Note'
responses:
"200":
$ref: "#/responses/ProtocolsResponse"

27. 27
API (Borrow)
function post_note (req, res) {
let content = note.value.data.attributes['content']
let context = note.value.data.attributes['context']
Note
.forge({content: content, context: context})
.save()
.then(function (response) {
let note = mapper.map(response, 'note')
return res.json(note)
})
.catch(function (err) {
...
})
}

28. 28
API (Borrow)
- Logically separated services
- DB ORM, serialisation (JSONAPI)
- Specification and validation (middleware)
- Interactive API docs (tooling)

29. 29
Logging (Borrow)
{
"name": "...",
"hostname": "...",
"pid": 7,
"level": 30,
"req": {
"requestID": "ab9add8f-ceb5-4015-b0d1-2b0b52772add",
"method": "POST",
"url": "/api/protocols",
"remoteAddress": "...",
"remotePort": ...,
"protocol": "https",
"xhr": false,
"headers": {
"host": "..."
}
},
"responseTime": 40.46, // milliseconds
"msg": "API request log",
"time": "...",
"v": 0.5.3
}
Bunyan

30. 30
Logging (Borrow + Buy)
CloudWatch Logs
{
"name": "...",
"hostname": "...",
"pid": 7,
"level": 30,
"req": {
"requestID": "ab9add8f-ceb5-4015-b0d1-2b0b52772add",
"method": "POST",
"url": "/api/protocols",
"remoteAddress": "...",
"remotePort": ...,
"protocol": "https",
"xhr": false,
"headers": {
"host": "..."
}
},
"responseTime": 40.46, // milliseconds
"msg": "API request log",
"time": "...",
"v": 0.5.3
}
Bunyan

31. 31
Infra (Borrow)
module "cloud" {
source = "./BioBrightCloud"
public-key-path = "...”
}
module "database" {
source = "./BioBrightDB"
vpc-id = "${module.cloud.vpc-id}"
database-release = "v0.1.4"
}
module "ember" {
source = "./EmberBioBright"
ember-release = "v0.3.1"
ember-environment = "${terraform.env}"
}
>> terraform apply

32. 32
Testing (Borrow)
parameters:
device_id_path:
name: device_id
in: path
description: ID of device fetch
required: true
type: string
x-example: "..."

33. 33
Testing (Borrow)
hooks.before('protocols > /api/protocols/notes > POST > 200 > application/json; charset=utf-8', function
(transaction) {
let testData = Math.random().toString(36).substring(2)
transaction.request.body = `{"data":{"attributes":{"content":"${testData}","context":{}}}}`
})
hooks.beforeEach(function (transaction) {
transaction.request.headers['Authorization'] = `Bearer ${jwt.token}`
})

34. 34
Deployment (Buy)
Elastic Beanstalk Elastic Beanstalk
+
ECS

35. 35
Summary
API spec Borrow OpenAPI
Logging Borrow + Buy Bunyan +
CloudWatch
Infra Borrow Terraform
Testing Borrow Dredd
Deployment Buy ElasticBeanStalk or
ECS

36. 36
1:1 Service : Swagger controller
1:1 Service : CloudWatch log group
1:1 Service : Terraform Module
1:1 Service : Repo (or Container)
Service Oriented Architecture

37. 37
MicroservicesMonoliths
Service
Oriented
Architecture

38. 38
LinkedIn: https://www.linkedin.com/in/harrisonrm/
Medium: https://medium.com/@rmharrison
Stack Overflow: https://stackoverflow.com/story/rmharrison