From Oredev 2014 http://oredev.org/2014/sessions/evolving-the-nuget-org-architecture After 3 years of usage growth though, NuGet.org needs to be more reliable, scalable, and maintainable, with the goal of 99.999% availability of package downloads. To achieve this, we’re evolving the architecture away from a monolithic website/service into several independent services, connected purely through HTTP. Come learn how we’re starting to use Command Query Responsibility Segregation (CQRS), JSON-LD/Linked Data, and event sourcing.

1. Evolving the nuget.org
Architecture
Jeff Handley
@JeffHandley

4. 275 000 000
Package downloads

5. 265 000
Total packages

6. 28 000
Unique package IDs

7. 7 500 000
Requests per day

8. 1 500 000
Searches per day

9. 700 000
Package downloads per day

10. 550
Package uploads per day

11. 60
User registrations per day

12. 85
Requests per second

13. Uptime (October 2013 – September 2014)
99.86%
99.88%
99.91%
100.00%
99.95%
99.90%
99.85%
99.80%
package installation
and restore
feed / search registration, login,
and package uploads

14. http://lapulpadigital.files.wordpress.com/2013/12/simo
n-cowell-people-sound-bad-when-recorded.jpg

15. Line of Business application
Using familiar technology

16. API v2 architecture
SQL Azure
database
Azure
Blob
Storage
Gallery / API v2
Azure web role (3 instances)
EntityFramework
code-first
WCF Data
Services and
ASP.NET MVC
and Razor
OData
Search and
feed
requests
Website
requests
Content Delivery Network (CDN)
Package
downloads

17. http://www.thecoralgablesstory.com/2010/08/17/sellers-regret-
is-the-new-buyers-remorse-in-real-estate/

18. Basing architecture on usage
Instead of familiar technology

19. all other reads
71%
user registrations
0.001%
package downloads
9%
package uploads
0.01%
searches
20%

20. Avoiding failures
• Writes should not impact read or query performance
• Command-Query Responsibility Segregation
• Append-only system for incremental processing
• Reads should not require server compute
• Presentation models (views) are regenerated (and persisted) asynchronously
• The materialized views can then be treated as static documents on the CDN
• Queries should not require external resources
• Lucene search index can be held entirely in memory

21. Catalog and materialized views
Resolver metadata
Another catalog
HTML
Web site
catalog
LUCENE Search

22. Building the catalog
page0.json
A B C
page1.json
D E F
page2.json
G H I
index.json

23. Reading the catalog
index.json
page0.json
A B C
page1.json
D E F
page2.json
G H I

24. Commit timestamps
1 | 1 | 2
1 1 2
3 | 3 | 3
3 3 3
4 | 5 | 5
4 5 5
2 | 3 | 5

25. Incremental updates
1 | 1 | 2
1 1 2
3 | 3 | 3
3 3 3
4 | 5 | 5
4 5 5
2 | 3 | 5
Cursor: 45

26. Materializing views as blobs
Read new
catalog entries
Apply view
Identify blobs
to be written
Read any
existing blobs
Merge data
using RDF
Write the new
blob

27. http://jerryfahrni.com/2009/12/biometric-identification-and-facial-recognition/

28. Database
Server
http://jerryfahrni.com/2009/12/biometric-identification-and-facial-recognition/

29. What we planned
•Add API v3 support to nuget.org
• Update the NuGet client to use API v3
• Factor the server into NuGet packages
• Factor the client into NuGet packages

30. Design resource formats
• Search
• Dependency resolution
•Website rendering
• Other package metadata reads
• Gallery mirroring
• Custom metadata consumption scenarios

31. Representing a graph in JSON
• Collection+JSON and Collection.Next+JSON
• Very similar to ATOM
• Includes query templates
• JSON-API and most others
• Emphasis on RESTful CRUD
• Client specification of data shape in some
• We didn’t want to expose our raw data model
• Scenario-specific views instead

32. http://www.flickr.com/photos/foxypar4/1004464889/

33. JSON-LD
HTTP://JSON-LD.ORG/
{
"@context": "http://json-ld.org/contexts/person.jsonld",
"@id": "http://dbpedia.org/resource/John_Lennon",
"name": "John Lennon",
"born": "1940-10-09",
"spouse": "http://dbpedia.org/resource/Cynthia_Lennon"
}

34. Linked Data
• @context allows the JSON document to be treated as an RDF data-set
• RDF = Resource Definition Framework
• Fully-qualified names and relationships (URI triples)
• RDF data-sets benefits
• Easily merged and queried
• Idempotent
• Everything is namespaced
• Based on W3C standards
• RDF 1.0: 1999
• RDF 1.1: February 2014 - http://www.w3.org/RDF/
• JSON-LD: January 2014 - http://www.w3.org/TR/json-ld/ (W3C Recommendation)

35. Azure
Blob
Storage
API v3
search
(feed)
Search Service
Azure worker role (3+ instances)
Lucene.NET
Full index loaded into memory
Backend jobs
Azure VM
(1 instance)
SQL
Azure
warehouse Gallery / API v2
Azure web role (3+ instances)
Content Delivery Network (CDN)
Package
Downloads
SQL
Azure
database
Website
requests
API v3
Package
Metadata
Metrics Service
Azure website (3+ instances)

36. API v3 clients
• Get service index from CDN
• Links are followed to resources:
• Search service
• Dependency resolver views
• Other metadata views
• Packages
• Metrics service

37. http://preview.nuget.org/ver3-preview/index.json
Humanizer RavenDB.Client

38. http://readingafterbedtime.wordpress.com/2012/11/01/october-2012-in-review/

39. http://freethoughtblogs.com/biodork/2012/03/19/cross-country-connections-tricky/

40. API v2 client behavior locked
• Lots of existing clients in the wild
• All requests are made through a single Gallery pipeline
• Download requests
• Record statistics to database
• Redirect to the CDN to get the nupkg

41. Azure
Blob
Storage
API v3
search
(feed)
Search Service
Azure worker role (3+ instances)
Lucene.NET
Full Index Loaded into Memory
Backend jobs
Azure VM
(1 instance)
SQL
Azure
warehouse Gallery / API v2
Azure web role (3+ instances)
Content Delivery Network (CDN)
Package
Downloads
SQL
Azure
database
Website
requests
API v3
Package
Metadata
Metrics Service
Azure website (3+ instances)
API v2
OData

42. Search service integration
Gallery receives
OData request
Search queries
identified and
stopped
API v3
request to
search service
JSON-LD
response
Transformed
into OData XML
OData XML
returned

43. Metrics service integration
Gallery receives
download
request
Call to
database is
removed
API v3
request to
metrics service
JSON-LD
POST
Fire and forget
Redirect to
package on
CDN

44. Iterative success
• Usage-based priorities for availability
• JSON-LD as our API v3 resource format
• Scenario-focused API v3 subsystems
• API v2 gallery became the first API v3 client
• API v3 responses are transformed into API v2 responses
• Getting API v3 benefits for existing API v2 users

45. NUGET 3.0 – TRANSITIONING
FROM ODATA TO JSON-LD
Friday at 14:20 in KITT

46. Thanks
Come get NuGet stickers 
Gallery and Backend Services
http://github.com/NuGet
Catalog and Collectors
http://github.com/NuGet/NuGet.Services.Metadata
JSON-LD Processor
http://github.com/NuGet/json-ld.net
http://www.nuget.org/packages/json-ld.net
@jeffhandley | jeffhandley.com | jeff.handley@microsoft.com | blog.nuget.org