Merge pull request #1782 from sass/feat/cache-path-candidates

Handle permission errors when attempting to cache binaries

lib/extensions.js

@@ -5,6 +5,7 @@
 var eol = require('os').EOL,
   fs = require('fs'),
   pkg = require('../package.json'),
+  mkdir = require('mkdirp'),
   path = require('path'),
   defaultBinaryPath = path.join(__dirname, '..', 'vendor');
 
@@ -262,6 +263,79 @@ function getBinaryPath() {
 }
 
 /**
+ * An array of paths suitable for use as a local disk cache of the binding.
+ *
+ * @return {[]String} an array of paths
+ * @api public
+ */
+function getCachePathCandidates() {
+  return [
+    process.env.npm_config_sass_binary_cache,
+    process.env.npm_config_cache,
+  ].filter(function(_) { return _; });
+}
+
+/**
+ * The most suitable location for caching the binding on disk.
+ *
+ * Given the candidates directories provided by `getCachePathCandidates()` this
+ * returns the first writable directory. By treating the candidate directories
+ * as a prioritised list this method is deterministic, assuming no change to the
+ * local environment.
+ *
+ * @return {String} directory to cache binding
+ * @api public
+ */
+function getBinaryCachePath() {
+  var i,
+    cachePath,
+    cachePathCandidates = getCachePathCandidates();
+
+  for (i = 0; i < cachePathCandidates.length; i++) {
+    cachePath = path.join(cachePathCandidates[i], pkg.name, pkg.version);
+
+    try {
+      mkdir.sync(cachePath);
+      return cachePath;
+    } catch (e) {
+      // Directory is not writable, try another
+    }
+  }
+
+  return '';
+}
+
+/**
+ * The cached binding
+ *
+ * Check the candidates directories provided by `getCachePathCandidates()` for
+ * the binding file, if it exists. By treating the candidate directories
+ * as a prioritised list this method is deterministic, assuming no change to the
+ * local environment.
+ *
+ * @return {String} path to cached binary
+ * @api public
+ */
+function getCachedBinary() {
+  var i,
+    cachePath,
+    cacheBinary,
+    cachePathCandidates = getCachePathCandidates(),
+    binaryName = getBinaryName();
+
+  for (i = 0; i < cachePathCandidates.length; i++) {
+    cachePath = path.join(cachePathCandidates[i], pkg.name, pkg.version);
+    cacheBinary = path.join(cachePath, binaryName);
+
+    if (fs.existsSync(cacheBinary)) {
+      return cacheBinary;
+    }
+  }
+
+  return '';
+}
+
+/**
  * Does the supplied binary path exist
  *
  * @param {String} binaryPath
@@ -289,6 +363,9 @@ module.exports.hasBinary = hasBinary;
 module.exports.getBinaryUrl = getBinaryUrl;
 module.exports.getBinaryName = getBinaryName;
 module.exports.getBinaryPath = getBinaryPath;
+module.exports.getBinaryCachePath = getBinaryCachePath;
+module.exports.getCachedBinary = getCachedBinary;
+module.exports.getCachePathCandidates = getCachePathCandidates;
 module.exports.getVersionInfo = getVersionInfo;
 module.exports.getHumanEnvironment = getHumanEnvironment;
 module.exports.getInstalledBinaries = getInstalledBinaries;

scripts/install.js

@@ -93,34 +93,54 @@ function download(url, dest, cb) {
  */
 
 function checkAndDownloadBinary() {
-  if (sass.hasBinary(sass.getBinaryPath())) {
+  if (process.env.SKIP_SASS_BINARY_DOWNLOAD_FOR_CI) {
+    log.info('node-sass install', 'Skipping downloading binaries on CI builds');
     return;
   }
 
-  mkdir(path.dirname(sass.getBinaryPath()), function(err) {
-    if (err) {
-      log.error('node-sass install', err);
+  var cachedBinary = sass.getCachedBinary(),
+    cachePath = sass.getBinaryCachePath(),
+    binaryPath = sass.getBinaryPath();
+
+  if (sass.hasBinary(binaryPath)) {
+    log.info('node-sass build', 'Binary found at %s', binaryPath);
     return;
   }
 
-    download(sass.getBinaryUrl(), sass.getBinaryPath(), function(err) {
+  try {
+    mkdir.sync(path.dirname(binaryPath));
+  } catch (err) {
+    log.error('node-sass install', 'Unable to save binary to %s: %s', path.dirname(binaryPath), err);
+    return;
+  }
+
+  if (cachedBinary) {
+    log.info('node-sass install', 'Cached binary found at %s', cachedBinary);
+    fs.createReadStream(cachedBinary).pipe(fs.createWriteStream(binaryPath));
+    return;
+  }
+
+  download(sass.getBinaryUrl(), binaryPath, function(err) {
     if (err) {
       log.error('node-sass install', err);
       return;
     }
 
-      log.info('node-sass install', 'Binary saved at %s', sass.getBinaryPath());
-    });
-  });
-}
+    log.info('node-sass install', 'Binary saved at %s', binaryPath);
 
-/**
- * Skip if CI
- */
+    cachedBinary = path.join(cachePath, sass.getBinaryName());
 
-if (process.env.SKIP_SASS_BINARY_DOWNLOAD_FOR_CI) {
-  log.info('node-sass install', 'Skipping downloading binaries on CI builds');
-  return;
+    if (cachePath) {
+      log.info('node-sass install', 'Caching binary to %s', cachedBinary);
+
+      try {
+        mkdir.sync(path.dirname(cachedBinary));
+        fs.createReadStream(binaryPath).pipe(fs.createWriteStream(cachedBinary));
+      } catch (err) {
+        log.error('node-sass install', 'Failed to cache binary: %s', err);
+      }
+    }
+  });
 }
 
 /**

test/runtime.js

@@ -115,6 +115,27 @@ describe('runtime parameters', function() {
     });
 
   });
+
+  describe.skip('Sass Binary Cache', function() {
+    var npmCacheDir;
+    before(function() {
+      npmCacheDir = process.env.npm_config_cache;
+    });
+
+    beforeEach(function() {
+      delete process.env.npm_config_sass_binary_cache;
+    });
+
+    it('npm config variable', function() {
+      var overridenCachePath = '/foo/bar/';
+      process.env.npm_config_sass_binary_cache = overridenCachePath;
+      assert.equal(sass.getCachePath(), overridenCachePath);
+    });
+
+    it('With no value, falls back to NPM cache', function() {
+      assert.equal(sass.getCachePath(), npmCacheDir);
+    });
+  });
 });
 
 // describe('library detection', function() {