fix(perf): bulk-read get+read for massive speed

get.js

@@ -3,7 +3,6 @@
 const Promise = require('bluebird')
 
 const index = require('./lib/entry-index')
-const finished = Promise.promisify(require('mississippi').finished)
 const memo = require('./lib/memoization')
 const pipe = require('mississippi').pipe
 const pipeline = require('mississippi').pipeline
@@ -25,33 +24,35 @@ function getData (byDigest, cache, key, opts) {
     : memo.get(cache, key)
   )
   if (memoized && opts.memoize !== false) {
-    return Promise.resolve({
+    return Promise.resolve(byDigest ? memoized : {
       metadata: memoized.entry.metadata,
       data: memoized.data,
       digest: memoized.entry.digest,
       hashAlgorithm: memoized.entry.hashAlgorithm
     })
   }
-  const src = (byDigest ? getStreamDigest : getStream)(cache, key, opts)
-  let acc = []
-  let dataTotal = 0
-  let metadata
-  let digest
-  let hashAlgorithm
-  if (!byDigest) {
-    src.on('digest', d => {
-      digest = d
+  return (
+    byDigest ? Promise.resolve(null) : index.find(cache, key, opts)
+  ).then(entry => {
+    if (!entry && !byDigest) {
+      throw index.notFoundError(cache, key)
+    }
+    return read(cache, byDigest ? key : entry.digest, {
+      hashAlgorithm: byDigest ? opts.hashAlgorithm : entry.hashAlgorithm,
+      size: opts.size
+    }).then(data => byDigest ? data : {
+      metadata: entry.metadata,
+      data: data,
+      digest: entry.digest,
+      hashAlgorithm: entry.hashAlgorithm
+    }).then(res => {
+      if (opts.memoize && byDigest) {
+        memo.put.byDigest(cache, key, opts.hashAlgorithm, res)
+      } else if (opts.memoize) {
+        memo.put(cache, entry, res.data)
+      }
+      return res
     })
-    src.on('hashAlgorithm', d => { hashAlgorithm = d })
-    src.on('metadata', d => { metadata = d })
-  }
-  src.on('data', d => {
-    acc.push(d)
-    dataTotal += d.length
-  })
-  return finished(src).then(() => {
-    const data = Buffer.concat(acc, dataTotal)
-    return byDigest ? data : { metadata, data, digest, hashAlgorithm }
   })
 }
 

lib/content/read.js

@@ -4,11 +4,30 @@ const Promise = require('bluebird')
 
 const checksumStream = require('checksum-stream')
 const contentPath = require('./path')
+const crypto = require('crypto')
 const fs = require('graceful-fs')
 const pipeline = require('mississippi').pipeline
 
 Promise.promisifyAll(fs)
 
+module.exports = read
+function read (cache, address, opts) {
+  opts = opts || {}
+  const algo = opts.hashAlgorithm || 'sha512'
+  const cpath = contentPath(cache, address, algo)
+  return fs.readFileAsync(cpath, null).then(data => {
+    const digest = crypto.createHash(algo).update(data).digest('hex')
+    if (typeof opts.size === 'number' && opts.size !== data.length) {
+      throw sizeError(opts.size, data.length)
+    } else if (digest !== address) {
+      throw checksumError(address, digest)
+    } else {
+      return data
+    }
+  })
+}
+
+module.exports.stream = readStream
 module.exports.readStream = readStream
 function readStream (cache, address, opts) {
   opts = opts || {}
@@ -37,3 +56,19 @@ function hasContent (cache, address, algorithm) {
     }
   })
 }
+
+function sizeError (expected, found) {
+  var err = new Error('stream data size mismatch')
+  err.expected = expected
+  err.found = found
+  err.code = 'EBADSIZE'
+  return err
+}
+
+function checksumError (expected, found) {
+  var err = new Error('checksum failed')
+  err.code = 'EBADCHECKSUM'
+  err.expected = expected
+  err.found = found
+  return err
+}

test/content.read.js

@@ -2,6 +2,7 @@
 
 const Promise = require('bluebird')
 
+const bufferise = require('./util/bufferise')
 const crypto = require('crypto')
 const path = require('path')
 const Tacks = require('tacks')
@@ -13,45 +14,57 @@ const CacheContent = require('./util/cache-content')
 
 const read = require('../lib/content/read')
 
-test('readStream: returns a stream with cache content data', function (t) {
-  const CONTENT = 'foobarbaz'
+test('read: returns a Promise with cache content data', function (t) {
+  const CONTENT = bufferise('foobarbaz')
   const DIGEST = crypto.createHash('sha512').update(CONTENT).digest('hex')
   const fixture = new Tacks(CacheContent({
     [DIGEST]: CONTENT
   }))
   fixture.create(CACHE)
-  const stream = read.readStream(CACHE, DIGEST)
+  return read(CACHE, DIGEST).then(data => {
+    t.deepEqual(data, CONTENT, 'cache contents read correctly')
+  })
+})
+
+test('read.stream: returns a stream with cache content data', function (t) {
+  const CONTENT = bufferise('foobarbaz')
+  const DIGEST = crypto.createHash('sha512').update(CONTENT).digest('hex')
+  const fixture = new Tacks(CacheContent({
+    [DIGEST]: CONTENT
+  }))
+  fixture.create(CACHE)
+  const stream = read.stream(CACHE, DIGEST)
   stream.on('error', function (e) { throw e })
   let buf = ''
   stream.on('data', function (data) { buf += data })
   stream.on('end', function () {
     t.ok(true, 'stream completed successfully')
-    t.equal(CONTENT, buf, 'cache contents read correctly')
+    t.deepEqual(bufferise(buf), CONTENT, 'cache contents read correctly')
     t.end()
   })
 })
 
-test('readStream: allows hashAlgorithm configuration', function (t) {
+test('read.stream: allows hashAlgorithm configuration', function (t) {
   const CONTENT = 'foobarbaz'
   const HASH = 'whirlpool'
   const DIGEST = crypto.createHash(HASH).update(CONTENT).digest('hex')
   const fixture = new Tacks(CacheContent({
     [DIGEST]: CONTENT
   }, HASH))
   fixture.create(CACHE)
-  const stream = read.readStream(CACHE, DIGEST, { hashAlgorithm: HASH })
+  const stream = read.stream(CACHE, DIGEST, { hashAlgorithm: HASH })
   stream.on('error', function (e) { throw e })
   let buf = ''
   stream.on('data', function (data) { buf += data })
   stream.on('end', function () {
     t.ok(true, 'stream completed successfully, off a sha512')
-    t.equal(CONTENT, buf, 'cache contents read correctly')
+    t.deepEqual(buf, CONTENT, 'cache contents read correctly')
     t.end()
   })
 })
 
-test('readStream: errors if content missing', function (t) {
-  const stream = read.readStream(CACHE, 'whatnot')
+test('read.stream: errors if content missing', function (t) {
+  const stream = read.stream(CACHE, 'whatnot')
   stream.on('error', function (e) {
     t.ok(e, 'got an error!')
     t.equal(e.code, 'ENOENT', 'error uses ENOENT error code')
@@ -65,7 +78,7 @@ test('readStream: errors if content missing', function (t) {
   })
 })
 
-test('readStream: errors if content fails checksum', function (t) {
+test('read.stream: errors if content fails checksum', function (t) {
   const CONTENT = 'foobarbaz'
   const DIGEST = crypto.createHash('sha512').update(CONTENT).digest('hex')
   const fixture = new Tacks(CacheContent({

test/util/bufferise.js

@@ -0,0 +1,8 @@
+'use strict'
+
+module.exports = bufferise
+function bufferise (string) {
+  return Buffer.from
+  ? Buffer.from(string, 'utf8')
+  : new Buffer(string, 'utf8')
+}