Nimrod: MongoDB Shell in NodeJS (JSConfUY 2015)

Nimrod: MongoDB Shell in NodeJS (JSConfUY 2015)

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  Nimrod: MongoDB Shellin NodeJS Valeri Karpov NodeJS Engineer, MongoDB www.thecodebarbarian.com github.com/vkarpov15 @code_barbarian
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  * What is thistalk about? •Why a NodeJS shell? •Note: not an officially sponsored project •Going off the beaten trail in JS •NodeJS repl module •Proxies in ECMAScript 6 •“Synchronous” I/O using fibers •Demos
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  * What’s the MongoDBShell For? •REPL for interfacing with MongoDB •Basic find operations for debugging •.explain() your queries
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  * What’s the MongoDBShell For? •Server administration
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  * Two Modes •Interactive -type at a REPL •Scripting - execute a file •Mongo shell focuses on interactive mode •Without I/O, scripting mode is limited
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  * Why Write Shellin NodeJS? •Very old V8 - no ES6 •MongoDB shell is a limited scripting environment • No I/O • No environment variables • Non-standard JS environment - limited module support •Want to do simple tasks like: • pull credentials from config without copy/paste • write results of a set of queries to a file • utilize moment in the shell
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  * NodeJS Shell Challenges •Needa REPL •db.collectionName.findOne() - how to make . collectionName access query the database? •Need synchronous I/O •The core features for understanding nimrod’s internals
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  * The Core Noderepl Package •Underrated Node feature •Can easily create repls to manage your servers
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  * The Core Noderepl Package •Basic example
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  * Contexts and repl •Contextsmake repl actually useful •Define “global” variables for the repl
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  * ECMAScript 6 Proxies •Moregeneric Object.defineProperty() •Great talk by JavaScript creator Brandon Eich
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  * ECMAScript 6 Proxies •Moregeneric Object.defineProperty() •Object.defineProperty(obj, ‘a’, { get: function() {} }); •Great talk by JavaScript creator Brandon Eich
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  * Why Proxies? •db.collectionName.find() ←collectionName should really be a function call •Difficult to sync with db on which collections exist •Hard to get this right without proxies •Note: proxies are only in node 0.12 •Also need --harmony --harmony_proxies flags
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  * More About Proxies •An80/20 Guide to ECMAScript 6 Proxies on my blog
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  * Coroutines for I/O •NodeJSconcurrency: great for servers, not for scripts •Fibers: seemingly synchronous I/O
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  * Coroutines for I/O •Callbacksare awesome for servers • See Callback Hell is a Myth •But not for scripting •Terseness and syntactic sugar are key
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  * Why Sync-ish I/O? •Canfake on REPL with asynchronous eval + promises •Much harder to fake in scripting mode:
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  * Nimrod Examples •Now youunderstand nimrod’s core principles •Time to see it in action :)
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  * Auth From Environment
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  * Writing Query Outputto a File
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  * Using NodeJS Packages
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  * •Contributors welcome! npmjs.org/package/nimrod •MoreNodeJS+MongoDB content at: • www.thecodebarbarian.com • Twitter: @code_barbarian Thanks for Listening!