CouchDB Day NYC 2017: Introduction to CouchDB 2.0
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Bradley Holt gave a presentation on Apache CouchDB 2.0, which introduced new features such as clustering, shards and replicas, Mango querying, and per-user databases. The presentation demonstrated how to connect to and interact with CouchDB through the HTTP API using the http-console tool, including creating databases and documents, retrieving documents, adding attachments, conditional requests, and deleting documents.
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CouchDB Day NYC 2017: Introduction to CouchDB 2.0
- 1. Apache CouchDB Developer Day Bradley Holt, Developer Advocate Thursday, February 9, 2017 Introducing Apache CouchDB 2.0 @BradleyHolt
- 2. @BradleyHolt
- 4. IBM Cloud Data Services Open for Data A comprehensive portfolio of open source data services
- 5. What is Apache CouchDB?
- 6. Document Database Apache CouchDB is a JSON document database
- 7. HTTP API Apache CouchDB is accessed through an HTTP API @BradleyHolt GET / GET /db/docPOST /db DELETE /db/doc PUT /db/doc PUT /db
- 8. Peer-to-Peer Replication @BradleyHolt Cloudant SyncCouchDB PouchDB CouchDB Replication Protocol CouchDB
- 9. What's new in CouchDB 2.0?
- 12. Shards and Replicas q=8 – Number of shards – One or more shards per node – Cannot have more nodes than shards r=2 – Read quorum w=2 – Write quorum n=3 – Number of replicas of every document @BradleyHolt CouchDB node1 CouchDB node2 CouchDB node3
- 13. Mango Declarative indexes MongoDB-style query language You can still use map/reduce views @BradleyHolt
- 16. What else is new? Improved database compaction Faster index updates New _bulk_get endpoint for optimized replication View-based filters in _changes feed Filter _changes feed with _doc_ids _all_docs and _changes will support attachments=true @BradleyHolt
- 19. Apache CouchDB 2.0 Sandbox Cluster Try Apache CouchDB 2.0 on an IBM Cloudant sandbox cluster @BradleyHolt
- 20. http-console
- 21. http-console $ npm install http-console -g @BradleyHolthttps://github.com/cloudhead/http-console
- 22. http-console $ npm install http-console -g $ http-console 127.0.0.1:5984 @BradleyHolthttps://github.com/cloudhead/http-console
- 23. http-console $ npm install http-console -g $ http-console 127.0.0.1:5984 > http-console 0.6.3 > Welcome, enter .help if you're lost. > Connecting to 127.0.0.1 on port 5984. @BradleyHolthttps://github.com/cloudhead/http-console
- 25. http-console http://127.0.0.1:5984/> GET / @BradleyHolthttps://github.com/cloudhead/http-console
- 26. http-console http://127.0.0.1:5984/> GET / HTTP/1.1 200 OK Content-Type: text/plain; charset=utf-8 { couchdb: 'Welcome', version: '9afa6a0', vendor: { name: 'The Apache Software Foundation' } } @BradleyHolthttps://github.com/cloudhead/http-console
- 30. http-console $ http-console https://bradley-holt.cloudant.com > http-console 0.6.3 > Welcome, enter .help if you're lost. > Connecting to bradley-holt.cloudant.com on port 443. @BradleyHolthttps://github.com/cloudhead/http-console
- 33. http-console https://bradley-holt.cloudant.com:443/> GET / HTTP/1.1 200 OK Content-Type: application/json { couchdb: 'Welcome', version: '9d28c57', vendor: { name: 'IBM Cloudant', version: '5331', variant: 'paas' }, features: [ 'geo' ] } @BradleyHolthttps://github.com/cloudhead/http-console
- 36. Exploring the CouchDB API
- 37. Connecting to CouchDB 2.0 $ http-console root:passw0rd@127.0.0.1:5984 --json @BradleyHolt
- 38. Connecting to CouchDB 2.0 $ http-console root:passw0rd@127.0.0.1:5984 --json > http-console 0.6.3 > Welcome, enter .help if you're lost. > Connecting to 127.0.0.1 on port 5984. @BradleyHolt
- 39. Connecting to IBM Cloudant $ http-console https://bradley-holt:passw0rd@bradley-holt.cloudant.com --json @BradleyHolt
- 40. Connecting to IBM Cloudant $ http-console https://bradley-holt:passw0rd@bradley-holt.cloudant.com --json > http-console 0.6.3 > Welcome, enter .help if you're lost. > Connecting to bradley-holt.cloudant.com on port 443. @BradleyHolt
- 43. Request Headers /> .headers Accept: application/json Content-Type: application/json Authorization: Basic cm9vdDorMi95N3Y2aA== Host: 127.0.0.1 @BradleyHolt
- 45. PUT a Database /> PUT /kittens @BradleyHolt
- 46. PUT a Database /> PUT /kittens ... @BradleyHolt
- 47. PUT a Database /> PUT /kittens ... HTTP/1.1 201 Created Content-Type: application/json Location: http://127.0.0.1/kittens { ok: true } @BradleyHolt
- 48. PUT a Database Again /> @BradleyHolt
- 49. PUT a Database Again /> PUT /kittens @BradleyHolt
- 50. PUT a Database Again /> PUT /kittens ... @BradleyHolt
- 51. PUT a Database Again /> PUT /kittens ... HTTP/1.1 412 Precondition Failed Content-Type: application/json { error: 'file_exists', reason: 'The database could not be created, the file already exists.' } @BradleyHolt
- 53. POST a Document /> /kittens @BradleyHolt
- 55. POST a Document /kittens> POST / @BradleyHolt
- 56. POST a Document /kittens> POST / ... @BradleyHolt
- 57. POST a Document /kittens> POST / ... { "_id": "mittens", "age_weeks": 10, "weight_kilograms": 0.997 } @BradleyHolt
- 58. POST a Document /kittens> POST / ... { "_id": "mittens", "age_weeks": 10, "weight_kilograms": 0.997 } HTTP/1.1 201 Created Content-Type: application/json Location: http://127.0.0.1/kittens/mittens { ok: true, id: 'mittens', rev: '1-e665a40d9ea9711c983e907f0b0b6e8a' } @BradleyHolt
- 60. GET All Documents /kittens> GET /_all_docs @BradleyHolt
- 61. GET All Documents /kittens> GET /_all_docs HTTP/1.1 200 OK Content-Type: application/json Etag: "92afa0f309a9fd9f140cd31ff5000b5c" { total_rows: 1, offset: 0, rows: [ { id: 'mittens', key: 'mittens', value: { rev: '1-e665a40d9ea9711c983e907f0b0b6e8a' } } ] } @BradleyHolt
- 63. GET a Document /kittens> GET /mittens @BradleyHolt
- 64. GET a Document /kittens> GET /mittens HTTP/1.1 200 OK Content-Type: application/json Etag: "1-e665a40d9ea9711c983e907f0b0b6e8a" { _id: 'mittens', _rev: '1-e665a40d9ea9711c983e907f0b0b6e8a', age_weeks: 10, weight_kilograms: 0.997 } @BradleyHolt
- 66. PUT an Attachment /kittens> .headers @BradleyHolt
- 67. PUT an Attachment /kittens> .headers Accept: application/json Content-Type: application/json Authorization: Basic cm9vdDorMi95N3Y2aA== Host: 127.0.0.1 @BradleyHolt
- 68. PUT an Attachment /kittens> .headers Accept: application/json Content-Type: application/json Authorization: Basic cm9vdDorMi95N3Y2aA== Host: 127.0.0.1 /kittens> Content-Type: image/gif @BradleyHolt
- 70. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a @BradleyHolt
- 71. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a ... @BradleyHolt
- 72. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a ... R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs= @BradleyHolt
- 73. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a ... R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs= HTTP/1.1 201 Created Content-Type: application/json Location: http://127.0.0.1/kittens/mittens/photo { ok: true, id: 'mittens', rev: '2-d858e51453a5785bafe517b7eddc5a98' } @BradleyHolt
- 74. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a ... R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs= HTTP/1.1 201 Created Content-Type: application/json Location: http://127.0.0.1/kittens/mittens/photo { ok: true, id: 'mittens', rev: '2-d858e51453a5785bafe517b7eddc5a98' } /kittens> @BradleyHolt
- 75. PUT an Attachment /kittens> PUT /mittens/photo?rev=1-e665a40d9ea9711c983e907f0b0b6e8a ... R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs= HTTP/1.1 201 Created Content-Type: application/json Location: http://127.0.0.1/kittens/mittens/photo { ok: true, id: 'mittens', rev: '2-d858e51453a5785bafe517b7eddc5a98' } /kittens> Content-Type: application/json @BradleyHolt
- 77. GET an Attachment /kittens> GET /mittens/photo @BradleyHolt
- 78. GET an Attachment /kittens> GET /mittens/photo HTTP/1.1 200 OK Content-Type: image/gif Etag: "UsqjdPnY6ApD2ENFOglFHg==" R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs= @BradleyHolt
- 80. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" @BradleyHolt
- 81. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" /kittens> @BradleyHolt
- 82. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" /kittens> GET /mittens/photo @BradleyHolt
- 83. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" /kittens> GET /mittens/photo HTTP/1.1 304 Not Modified @BradleyHolt
- 84. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" /kittens> GET /mittens/photo HTTP/1.1 304 Not Modified /kittens> @BradleyHolt
- 85. Conditional Caching /kittens> If-None-Match: "UsqjdPnY6ApD2ENFOglFHg==" /kittens> GET /mittens/photo HTTP/1.1 304 Not Modified /kittens> If-None-Match: @BradleyHolt
- 87. DELETE a Document /kittens> DELETE /mittens @BradleyHolt
- 88. DELETE a Document /kittens> DELETE /mittens HTTP/1.1 409 Conflict Content-Type: application/json { error: 'conflict', reason: 'Document update conflict.' } @BradleyHolt
- 90. DELETE a Document /kittens> HEAD /mittens @BradleyHolt
- 91. DELETE a Document /kittens> HEAD /mittens HTTP/1.1 200 OK Etag: "2-d858e51453a5785bafe517b7eddc5a98" @BradleyHolt
- 93. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" @BradleyHolt
- 94. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" /kittens> @BradleyHolt
- 95. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" /kittens> DELETE /mittens @BradleyHolt
- 96. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" /kittens> DELETE /mittens HTTP/1.1 200 OK Content-Type: application/json { ok: true, id: 'mittens', rev: '3-d0780627ddff7a7f536fe273100cec41' } @BradleyHolt
- 97. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" /kittens> DELETE /mittens HTTP/1.1 200 OK Content-Type: application/json { ok: true, id: 'mittens', rev: '3-d0780627ddff7a7f536fe273100cec41' } /kittens> @BradleyHolt
- 98. DELETE a Document /kittens> If-Match: "2-d858e51453a5785bafe517b7eddc5a98" /kittens> DELETE /mittens HTTP/1.1 200 OK Content-Type: application/json { ok: true, id: 'mittens', rev: '3-d0780627ddff7a7f536fe273100cec41' } /kittens> If-Match: @BradleyHolt
- 102. Replication /kittens> .. /> DELETE /kittens @BradleyHolt
- 103. Replication /kittens> .. /> DELETE /kittens HTTP/1.1 200 OK Content-Type: application/json { ok: true } @BradleyHolt
- 107. Replication /> POST /_replicate ... { "create_target": true, "source": "https://bradley-holt.cloudant.com/kittens", "target": "kittens" } @BradleyHolt
- 108. Replication /> POST /_replicate ... { "create_target": true, "source": "https://bradley-holt.cloudant.com/kittens", "target": "kittens" } HTTP/1.1 200 OK Content-Type: application/json { ok: true, session_id: '9f7bd286a0001ece5bf0bf65dd83c5ab', source_last_seq: '5- g1AAAAFDeJzLYWBgYMlgTmGQT0lKzi9KdUhJMtVLykxPyilN1UvOyS9NScwr0ctLLckBKmRKZEiy____f1 YiA6oWQ9xakhyAZFI9SFcGcyJzLpDHbplmZmxkaULYBKIdlscCJBkagBTQov2kuA- i8wBEJ9iNTGA3mhoampmnGBA2JQsA1LtoyA', … } @BradleyHolt
- 115. Mango /kittens> POST /_index ... { "index": { "fields": [ "age_weeks", "weight_kilograms" ] } } @BradleyHolt
- 116. Mango /kittens> POST /_index ... { "index": { "fields": [ "age_weeks", "weight_kilograms" ] } } HTTP/1.1 200 OK Content-Type: application/json { result: 'created', id: '_design/e19dde7f518129a966ebe072edc66be88d54e694', name: 'e19dde7f518129a966ebe072edc66be88d54e694' } @BradleyHolt
- 117. @BradleyHolt
- 121. Mango /kittens> POST /_find ... { "selector": { "age_weeks": { "$gte": 7, "$lte": 10 } }, "fields": [ "_id", "age_weeks" ] } @BradleyHolt
- 122. Mango /kittens> POST /_find ... { "selector": { "age_weeks": { "$gte": 7, "$lte": 10 } }, "fields": [ "_id", "age_weeks" ] } HTTP/1.1 200 OK Content-Type: application/json { docs: [ { _id: 'tiger', age_weeks: 7 }, { _id: 'daisy', age_weeks: 9 }, { _id: 'mittens', age_weeks: 10 } ] } @BradleyHolt
- 123. @BradleyHolt
- 127. Mango /kittens> POST /_find ... { "selector": { "age_weeks": { "$gte": 0 }, "weight_kilograms": { "$gte": 0.5, "$lte": 1 } }, "fields": [ "_id", "weight_kilograms" ] } @BradleyHolt
- 128. Mango /kittens> POST /_find ... { "selector": { "age_weeks": { "$gte": 0 }, "weight_kilograms": { "$gte": 0.5, "$lte": 1 } }, "fields": [ "_id", "weight_kilograms" ] } HTTP/1.1 200 OK Content-Type: application/json { docs: [ { _id: 'tiger', weight_kilograms: 0.726 }, { _id: 'daisy', weight_kilograms: 0.816 }, { _id: 'mittens', weight_kilograms: 0.997 } ] } @BradleyHolt
- 129. @BradleyHolt
- 130. Contributing
- 132. Offline First
- 134. Offline First Lack of connectivity is not an error condition.
- 140. Cloudant Sync
- 141. Cloudant FoodTracker
- 142. Cloudant FoodTracker
- 146. Offline Camp Berlin April 28th - May 1st, Berlin, Germany
- 148. Image Credits paper by malik, on Flickr <https://flic.kr/p/aZjTXv> person by Tim Morgan, on Flickr <https://flic.kr/p/7DSF5> database by Tim Morgan, on Flickr <https://flic.kr/p/7DUk5> gear by Tim Morgan, on Flickr <https://flic.kr/p/7DSF1> Mango with section on a white background by bangdoll, on Flickr <https://flic.kr/p/9CBP2h> @BradleyHolt
Notas del editor
- A comprehensive portfolio of open source data services A rich, curated open data catalog that adds meaning to your data Services that connect integrate hybrid data from internal and external data sources and connect to analytics offerings Fully managed and open for business 24/7/365
- Brings horizontal scalability to CouchDB CouchDB 2.0 can be configured for standalone mode
- Can add and remove nodes to a cluster at will Cannot reshard, so preshard instead Presharding, no resharding If you need more shards, create a new cluster and migrate over
- enable If set to true, couch_peruser ensures that a private per-user database exists for each document in _users. These databases are writable only by the corresponding user. Databases are in the following form: userdb-{hex encoded username}. delete_dbs If set to true and a user is deleted, the respective database gets deleted as well.
- The Cloudant and CouchDB 2.0 codebases are merging Clustering and Mango have been available on Cloudant for quite awhile
- HTTP Basic authentication is a simple way to authenticate with an HTTP server Other approaches, such as cookies and OAuth, are often used as well
- Resources can be represented in different content types
- … I hope that I’ve convinced you that you shouldn’t build your apps to rely on a network connection. But what’s the alternative? You have two basic options: graceful degradation or progressive enhancement. Graceful degradation involves building your app as usual, assuming that it will have a good network connection, and then gracefully handling the resultant errors when the network connection inevitably does not work. The progressive enhancement approach involves assuming that, as a baseline, your app will not have a working network connection. Then, your app can be progressively enhanced to take advantage of network connectivity when available.
- The progressive enhancement approach is what we call Offline First. Don’t assume that lack of connectivity is an error condition. Build your app to work without a connection. Get updated content, sync your data, or enable features that aren’t practical to make work offline when the app is connected. Let users still interact with your app when there’s no reliable connection available.
- The term Offline First was first coined by Alex Feyerke in a 2013 A List Apart article. The open source Hoodie project (which Alex and others work on) was probably the first framework to embrace the Offline First moniker and approach. Around the same time that Hoodie was created PouchDB was also created. PouchDB is a JavaScript database that syncs. More recently, Service Workers were introduced into Google Chrome, enabling new Offline First use cases in web browsers. Firefox and Opera have also implemented Service Workers, and Microsoft Edge plans to support Service Workers as well.
- … If you’ve heard of Progressive Web Apps then some of what I’ve talked about probably sounds familiar. The basic idea of Progressive Web Apps is to combine the discoverability of web apps with the power of native mobile apps. As an end user, you browse to a Progressive Web App just like you would browse to any other website. As you use the app more-and-more, it gains additional native-app-like capabilities. For example, installation to your home screen or the ability to send you alerts and notifications.
- Google is currently making a big push for Progressive Web Apps and many companies have invested in building Progressive Web Apps. For example, The Weather Company, which IBM recently acquired, has built a Progressive Web App which allows them to send alerts and notifications to users. Progressive Web Apps are an opportunity for web developers to rethink how we approach building web apps. The market has clearly demonstrated that it likes the interaction model of native apps. There’s a lot that we can learn from how native apps are built. Don’t get me wrong, I’m a huge believer in the power of the open web. I don’t think we should just turn web apps into native apps and call it done. I do think that we can incorporate some of the best parts of native apps into how we build web apps while not losing the soul of the open web.
- I encourage you to also check out PouchDB. It’s not as lightweight as localForage, but it includes a bunch of awesome features that are probably worth the extra overhead. The most exciting feature of PouchDB is its ability to sync with anything that implements the CouchDB Replication Protocol. This, of course, includes Apache CouchDB. It also includes IBM Cloudant, a fully-managed cloud database that is based on CouchDB. PouchDB allows you to read and write data directly on the device, and then sync this data to the cloud when you have an internet connection. This makes create, read, update, and delete operations extremely fast as all of your data access happens locally.
- Not only can PouchDB run in a web browser, but it can also run in any JavaScript environment including in Node.js, in Apache Cordova or Ionic for hybrid mobile apps, in Electron for desktop apps, and even on a Tessel for Internet of Things (IoT) apps. Nolan Lawson, one of the core contributors to PouchDB, has written up some excellent demos of running PouchDB in these environments and others.
- Our team at IBM Cloudant also created open source Cloudant Sync libraries for iOS and Android, in case you prefer to build native mobile apps and would like to take an Offline First approach. While they have different APIs than PouchDB, these libraries, like PouchDB, store data locally on the device and can also sync with anything that implements the CouchDB Replication Protocol.
- … Our Developer Advocacy team has built several Offline First sample apps to help you learn how to build Offline First apps. Cloudant FoodTracker is an app that we created to demonstrate how to build an Offline First iOS app in Swift using Cloudant Sync. Apple provides a great tutorial on starting to develop iOS apps in Swift. The tutorial walks readers through creating a simple meal tracking app. The app allows users to view and edit a list of meals. Each meal includes a meal name, rating, and a photo.
- Apple’s FoodTracker is offline-only, meaning that all of the meal data is stored only on the device and the app provides no means of syncing that data to the cloud. Cloudant FoodTracker replaces the data layer with Cloudant Sync and then syncs with Cloudant or CouchDB.
- Field Work is a web app that allows offline editing and mapping of geospatial data. The idea of Field Work is to demonstrate how a company in a field-based industry, such as the utility industry, could benefit from an app which their field personnel could use even when disconnected.
- Field Work stores GeoJSON locally on the device in PouchDB. It uses Leaflet and Mapbox.js to render the geospatial data on a map. Read-only base map layers are synced from a Cloudant database to a PouchDB database on the device. An editable map layer is then synced between a separate Cloudant database and a separate PouchDB database on the device. There are other aspects to the app, including the ability create work orders.
- Location Tracker is another iOS sample app, written in Swift. The app tracks a user’s location as they move and stores this data in a local Cloudant Sync database, which is synced with Cloudant when an internet connection is available. As a user moves, and new locations are recorded, the app queries the server for points of interests near the user’s location. Blue pins mark each location recorded by the app. A blue line is drawn over the path the user has travelled. Each time the Location Tracker app records a new location a radius-based geo query is performed in Cloudant to find nearby points of interest.