Video and slides synchronized, mp3 and slide download available at URL http://bit.ly/2eapFFq. Michael Uzquiano talks about how to scale API to accept many items. He examines how to evolve the Evolution of ReST over HTTP to transactional, asynchronous bulk operations. He covers job descriptors, workers, the job queue and scaling workers across an API cluster elastically. He also talks about polling methods for job completion including HTTP long polling and WebSockets. Filmed at qconnewyork.com. Michael Uzquiano is Founder and CTO of CloudCMS and Alpaca.js Committer.

1. No REST
Real-Time Bulk Asynchronous APIs

2. InfoQ.com: News & Community Site
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Portuguese)
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Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
rest-evolution-async-operations

3. Presented at QCon New York
www.qconnewyork.com
Purpose of QCon
- to empower software development by facilitating the spread of
knowledge and innovation
Strategy
- practitioner-driven conference designed for YOU: influencers of
change and innovation in your teams
- speakers and topics driving the evolution and innovation
- connecting and catalyzing the influencers and innovators
Highlights
- attended by more than 12,000 delegates since 2007
- held in 9 cities worldwide

4. About me
• Michael Uzquiano
• Founder @ Cloud CMS
• First time dad, not getting much
sleep

5. Git

6. keep it simple

7. Building Blocks
• Services
• createNode()
• queryNodes()
• readNode(id)
• Object Methods
• update()
• del()
• transform(mimetype)

8. Building Blocks
• Services
• createNode()
• queryNodes()
• readNode(id)
• Object Methods
• update()
• del()
• transform(mimetype)
POST
POST
GET
PUT
DELETE
POST

9. Adding 3 Nodes
branch
.createNode({ “title”: “title1” })
.createNode({ “title”: “title2” })
.createNode({ “title”: “title3” });

10. Latency makes life tough
branch
.createNode({ “title”: “title1” })
.createNode({ “title”: “title2” })
.createNode({ “title”: “title3” });
100 ms
100 ms
100 ms

11. Life is not simple
branch
.readRepository(“repository1”)
.readBranch(“master”)
.queryNodes({
“category”: “my_category”
}).each(function) {
this.discount = 0.2;
this.update();
});

12. Problem: Latency
branch
.readRepository(“repository1”)
.readBranch(“master”)
.queryNodes({
“category”: “my_category”
}).each(function) {
this.discount = 0.2;
this.update();
});
100 ms
100 ms
100 ms
100 ms?

13. Problem: Payload Size
branch
.readRepository(“repository1”)
.readBranch(“master”)
.queryNodes({
“category”: “my_category”
}).each(function) {
this.discount = 0.2;
this.update();
});

14. Problem: No Transactions
App Server
Transaction
API Server
Transaction Op Log
Update #2
Update #1
Update #3
Update #1
Update #2

16. A Way Out?
helper.updateNodes({
“repositoryId”: repositoryId,
“branchId”: branchId,
“query”: {
“category”: “my_category”
},
“properties”: {
“discount”: 0.2
}
});

18. A Way Out?
helper.updateNodes({
“repositoryId”: repositoryId,
“branchId”: branchId,
“query”: {
“category”: “my_category”
},
“properties”: {
“discount”: 0.2
}
});
100 ms
}
}
query
upsert

19. Simplicity

20. Dev

21. Dev

22. Staging / Test
Dev

23. Production
Staging / Test
Dev

24. The hard problems
• Reduce Payload Size
• Multiple Calls -> Single Call
• Transactions (Rollback / Commit)

25. reducing payload

26. RFC 5789 (HTTP Patch)
• Modify an existing HTTP resource
• Send a “set of instructions” to modify resource
• Atomic
• Idempotent

27. Using HTTP PUT
PUT /repositories/{repositoryId}/branches/
{branchId}/nodes/{nodeId}
{
“title”: “My Title”,
“description”: “My Description”,
“discount”: 0.2
}

28. Using HTTP PATCH
PATCH /repositories/{repositoryId}/branches/
{branchId}/nodes/{nodeId}
{
“discount”: 0.2
}

29. Using HTTP PATCH
PATCH /repositories/{repositoryId}/branches/
{branchId}/nodes/{nodeId}
{
“discount”: 0.2
}
{
“title”: “My Title”,
“description”: “My Description”
}
Original JSON

30. Using HTTP PATCH
PATCH /repositories/{repositoryId}/branches/
{branchId}/nodes/{nodeId}
{
“discount”: 0.2
}
{
“title”: “My Title”,
“description”: “My Description”,
“discount”: 0.2
}
Modified JSON

31. RFC 6902 - JSON Patch
• Sequence of Operations to modify a JSON resource
• Operations
• add, remove, replace, move, copy, test

32. JSON Patch Example
{
“title”: “Hello World”,
“category”: “my_category”
}
Original JSON

33. JSON Patch Example
Original JSON
JSON Patch
{
“title”: “Hello World”,
“category”: “my_category”,
“discount”: 0.2
}
[{
“op”: “add”,
“path”: “discount”,
“value”: 0.2
}]

34. HTTP Patch and JSON Patch
PATCH /repositories/{repositoryId}/branches/
{branchId}/nodes/{nodeId}
[{
“op”: “add”,
“path”: “discount”,
“value”: 0.2
}]

35. Path-based Changes
• add
• remove
• replace
• move
• copy
• test

36. multiple calls

37. Multiple Resources

38. Creates

39. Deletes
X X

40. Updates
X X

41. Moves
X X

42. Operations Queue
• create
• update
• remove
• move
• copy

43. Partial Writes?
Lack of rollback or commit

44. Changesets

45. Let’s Say…
my:book
my:chapter
my:chapter
my:page
my:page
my:page
my:page
my:page

46. Create #1
my:book
my:chapter
my:page
my:page

47. Create #2
my:book
my:chapter
my:page
my:page
my:page

48. Create #3
my:book
my:chapter
my:chapter
my:page
my:page
my:page
my:page

49. Create #4
my:book
my:chapter
my:chapter
my:page
my:page
my:page
my:page
my:page

50. Changeset #1
my:chapter
my:page
my:page
C1

51. Changeset #2
my:chapter
my:page
my:page
my:page
C1
C2

52. Changeset #3
my:chapter
my:page
my:page
my:page
my:chapter
my:page
C1
C2
C3

53. Changeset #4
my:chapter
my:page
my:page
my:page
my:chapter
my:page
my:page
C1
C2
C3
C4

54. Lack of Transaction Boundaries
C0
C1 C2 C3 C4
C5

55. Transaction Boundaries
C0
C1 C2 C3 C4
C5
Read/Write Lock?
Accumulation vs commit

57. transactions

58. Branches
Long Running Transactions

59. Branches
C0
C1’
C5C1 C2
C2’ C3’ C4’
Fork Merge

60. Merge
• Detect collisions (various strategies)
• Automatically merge where possible (JSON Patch with merge
algorithm)
• JSON Schema validation
• Graph validation
• Transactional write (Hazelcast shout out)

61. Create a Transaction
var t = cloudcms.createTransaction(branch);

62. Create a Node
var t = cloudcms.createTransaction(branch);
t.create({
“title”: “Hello World”
});

63. Commit the Transaction
var t = cloudcms.createTransaction(branch);
t.create({
“title”: “Hello World”
});
t.commit(function(results) {
console.log(“Result: “ + results.success);
});

64. Client Side: Build Transaction
API ServerApp Server

65. Client Side: Build Transaction
API ServerApp Server
Create #1

66. Client Side: Build Transaction
API ServerApp Server
Create #1
Update #2

67. Client Side: Build Transaction
API ServerApp Server
Create #1
Update #2
Delete #3

68. Transaction
Client Side: Call commit()
App Server API Server
Transaction Op Log
Create #1
Update #2
Delete #3
Create #1
Update #2
Delete #3

69. Transaction Executes
App Server API Server
Transaction Op Log
Create #1
Update #2
Delete #3

70. Client polls for completion
App Server API Server
Transaction Op Log
Results
Create #1
Update #2
Delete #3

71. • Lower Latency
• Reduced Payload Size
• No Partial Writes / Reads
Pros

72. • Reuse / repeatability
• Custom “loader” code
Cons

73. packages

74. Packages
Package up objects, binaries and manifest (operations log) on client
Send over to API and say “deal with this”

75. Create Package
API ServerApp Server
Create #1

76. API ServerApp Server
Create #1
Update #2
Create Package

77. API ServerApp Server
Create #1
Update #2
Delete #3
Create Package

78. Transaction
App Server API Server
Package into Archive

79. Upload Archive to Server
App Server API Server
Transaction

80. Server Imports the Archive
App Server API Server
Work Items
Create #1
Update #2
Delete #3

81. Polls for completion
App Server API Server
Transaction Op Log
Results
Create #1
Update #2
Delete #3

82. Create a Package
var p = cloudcms.createPackage();

83. Add Nodes
var p = cloudcms.createPackage();
var node1 = p.addNode({ “title”: “title1” });
var node2 = p.addNode({ “title”: “title2” });

84. Add Binary Attachments
var p = cloudcms.createPackager();
var node1 = p.addNode({ “title”: “title1” });
var node2 = p.addNode({ “title”: “title2” });
var stream = fs.createReadStream(filePath);
var attachment1 = p.addAttachment(node2._doc,
“default”, stream);

85. Create the Archive
var p = cloudcms.createPackager();
var node1 = p.addNode({ “title”: “title1” });
var node2 = p.addNode({ “title”: “title2” });
var stream = fs.createReadStream(filePath);
var attachment1 = p.addAttachment(node2._doc,
“default”, stream);
var archive = p.package(“org.cloudcms”, “demo”,
“1.0”);

86. Upload the Archive
vault.uploadArchive(archive, function(results) {
console.log(“Success: “ + results.success);
});

87. Import the Archive
vault.uploadArchive(archive, function(results) {
console.log(“Success: “ + results.success);
});
branch.importArchive(“org.cloudcms”, “demo”,
“1.0”, function(results) {
console.log(“Success: “ + results.success);
});

89. Production
Staging / Test
Dev

90. The hard problems
• Reduce Payload Size
• Multiple Calls
• Transactions

92. Michael Uzquiano
@uzquiano
https://www.cloudcms.com

93. Watch the video with slide synchronization on
InfoQ.com!
https://www.infoq.com/presentations/rest-
evolution-async-operations