With the massive adoption of microservices and serverless functions-based cloud native architectures, the need for cloud native programming languages is on the rise. Today, the apps we write increasingly integrate with programmable endpoints such as data, microservices, APIs, and serverless functions. Yet, with existing languages, developers have to take responsibility to solve the hard problems of integration such as security, resiliency, transactions, stream processing, workflows, protocol handling, data formats, and mediation. Ballerina is a cloud native programming language specializing in integration. It makes the development of microservices that integrate with other systems simpler by bringing fundamental concepts, ideas, and tools of distributed system integration into the language. In this session, we will give you an in-depth overview of Ballerina’s language features: high-level network abstractions such as endpoints, services and resources, network-aware type system, error handling, and the concurrency model built on the sequence diagram metaphor.

1. Writing Microservices
Anjana Fernando
Director, Ecosystem Engineering, WSO2 Inc.

2. ○ Network abstractions
○ Network-aware type system
○ Concurrency
○ Resiliency
○ Security
○ Test driven development
○ Observability
○ Cloud-native deployment
Writing Microservices

3. Network Abstractions

4. Endpoints...

5. Endpoints...

6. Endpoints...

7. Endpoints...

8. Endpoints...

9. Endpoints...

10. Endpoints...

11. Endpoints...

12. Endpoints...

13. Endpoints...

14. Endpoints...

15. Endpoints...

16. Endpoints...

17. Endpoints...

18. Endpoints...

19. ○ Protocols
○ HTTP/S
○ HTTP2
○ GRPC
○ WebSocket
○ JMS
Service Endpoints

20. Client Endpoints

21. Network-aware Type System

22. json

23. json

24. json

25. json...

26. json...

27. json...

28. xml

29. xml

30. xml

31. xml

32. xml...

33. xml...

34. xml...

35. Union types

36. Union types

37. Union types

38. match / but

39. match / but

40. match / but

41. match / but...

42. match / but...

43. match / but...

44. Error handling

45. Error handling...

46. check

47. check

48. check...

49. check...

50. Concurrency

51. Workers

52. Workers...

53. Workers...

54. Workers...

55. Async

56. Async...

57. Async...

58. Fork/Join

59. Fork/Join

60. Fork/Join

61. Resiliency

62. caller hello
response
Simpson quotes
GET
quote
twitter
tweet (quote)
response

63. caller hello
response
Simpson quotes twitter
tweet
response
Open
Circuit Breaker
logic

64. ○ Timeout
○ Retry
○ Failover
○ Load balancing
○ Circuit breaker
○ Transactions
Ballerina Resiliency Features

65. Security

66. ○ Secure defaults / Built-in features
○ XML External Entity Injection (XXE) prevention
○ OCSP validation for SSL/TLS certificates
○ CRL validation for SSL/TLS certificates
○ Config API reading encrypted passwords or secrets
○ Taint analysis
○ Authentication / Authorization
Ballerina Security Features

67. Taint Analysis
public native function select
(@sensitive string sqlQuery,
typedesc? recordType,
boolean loadToMemory = false,
Param... parameters)
returns @tainted table|error;
@sensitive [parameter]
Security Sensitive Parameters
(Passing untrusted data to the
parameter can lead to a security risk)
returns @tainted
Returns Untrusted Data
Signature is derived
if not explicitly mentioned.
public native function read
(@sensitive int numberOfChars)
returns @tainted string|error;
public function execute
(@sensitive string httpVerb,
@sensitive string path,
Request|string|xml|json|byte[]
|io:ByteChannel|mime:Entity[]|()
message)
returns Response|error;
public native function getHeaders
(@sensitive string headerName)
returns @tainted string[];
ballerina/sql
ballerina/io
ballerina/http
ballerina/mime

68. SQL Injection Prevention
sql:Parameter param_id = { sqlType:
sql:TYPE_INTEGER, value: params.id };
var selectRet = testDB->select
("SELECT * FROM student WHERE id = ?", (),
param_id);
match selectRet {
table tableReturned => {
if (td.hasNext()) {
res.setPayload("Found!");
} else {
res.setPayload("Not Found!");
}
td.close();
}
error err => throw err;
}
var params = req.getQueryParams();
var selectRet = testDB->select
("SELECT * FROM student WHERE id = "
+ params.id, ());
match selectRet {
table tableReturned => {
if (td.hasNext()) {
res.setPayload("Found!");
} else {
res.setPayload("Not Found!");
}
td.close();
}
error err => throw err;
}
Correct Approach:
error: ./sqli_fail.bal:23:40: tainted value passed to
sensitive parameter 'sqlQuery'

69. Inbound Authentication & Authorization
Authentication
Filter
Authorization
Filter
Authentication
Provider
Resource
Request
Basic Auth
OAuth
JWT
Certificate
Response
HTTP JMS
Config File
LDAP
AD
DB
User Storage

70. Observability

71. Ballerina Observability
○ Services and client connectors are observable by default
○ Database connectors (e.g., SQL) have semantic tags to provide additional information for
metrics and tracing
○ Ballerina user API for emitting custom observability data
○ Ballerina directly supported technologies:-
○ Metrics Collection
○ Prometheus, Honeycomb
○ Tracing (via OpenTracing)
○ Jaeger, Zipkin, Honeycomb
○ Logging
○ Flat files
○ ELK stack
○ Visualization
○ Grafana

72. Metrics Monitoring

73. Distributed Tracing

74. Logging

75. Test Driven Development

76. Testing Microservices
Functions
Services
Packages
Deployment
Updated source: https://martinfowler.com/articles/microservice-testing
Ballerina Unit Tests
Ballerina Service Tests
Ballerina Service Tests
Google Container Structure
Tests / Falco for K8s

77. Cloud Native Deployment

78. Ballerina Deployment Options
○ Standalone binary
○ Docker/Kubernetes deployment
○ Annotation based Docker/Kubernetes artifact generation
○ No manual Kubernetes yaml creation
○ No Ballerina code changes

79. Demo

80. THANK YOU