feat: cache at loader level

This makes the cache global, per process, so that it can be re-used when resolving deps.

Author: dominykas

lib/deps.js

@@ -9,10 +9,9 @@ const Tmp = require('tmp');
 const Package = require('./package');
 const Utils = require('./utils');
 
-const internals = {};
-
-
-internals.log = Debug('detect-node-support');
+const internals = {
+    log: Debug('detect-node-support')
+};
 
 
 internals.resolve = async ({ packageJson, lockfile }, options) => {

lib/loader.js

@@ -11,6 +11,7 @@ const Wreck = require('@hapi/wreck');
 const Utils = require('./utils');
 
 const internals = {
+    cache: new Map(),
     log: Debug('detect-node-support:loader'),
     error: Debug('detect-node-support:error')
 };
@@ -95,9 +96,18 @@ internals.createRepositoryLoader = (repository) => {
             const url = `https://raw.githubusercontent.com/${parsedRepository.full_name}/HEAD/${filename}`;
             internals.log('Loading: %s', url);
 
+            if (options === undefined && internals.cache.has(url)) {
+                internals.log('From cache: %s', url);
+                return internals.cache.get(url);
+            }
+
             try {
                 const { payload } = await Wreck.get(url, options);
 
+                if (options === undefined) {
+                    internals.cache.set(url, payload);
+                }
+
                 internals.log('Loaded: %s', url);
                 return payload;
             }
@@ -164,3 +174,9 @@ exports.create = ({ path, repository, packageName }) => {
 
     return internals.createPathLoader(path);
 };
+
+
+exports.clearCache = () => {
+
+    internals.cache = new Map();
+};

lib/travis/imports.js

@@ -1,6 +1,5 @@
 'use strict';
 
-const Debug = require('debug');
 const Yaml = require('js-yaml');
 
 const Loader = require('../loader');
@@ -14,9 +13,6 @@ const internals = {
 };
 
 
-internals.log = Debug('detect-node-support');
-
-
 internals.normalizeImports = (travisYaml, { relativeTo }) => {
 
     return Utils.toArray(travisYaml.import)
@@ -53,12 +49,7 @@ internals.normalizeImports = (travisYaml, { relativeTo }) => {
 };
 
 
-internals.loadSource = async (source, { loadFile, cache }) => {
-
-    if (cache[source]) {
-        internals.log('Returning cached %s', source);
-        return cache[source];
-    }
+internals.loadSource = async (source, { loadFile }) => {
 
     let path = source;
 
@@ -70,14 +61,11 @@ internals.loadSource = async (source, { loadFile, cache }) => {
         loadFile = loader.loadFile;
     }
 
-    internals.log('Loading %s', source);
-    const result = await loadFile(path);
-    cache[source] = result;
-    return result;
+    return loadFile(path);
 };
 
 
-exports.apply = async (yaml, { loadFile, relativeTo, cache = new Map() }) => {
+exports.apply = async (yaml, { loadFile, relativeTo }) => {
 
     if (!yaml.import) {
         return;
@@ -87,14 +75,14 @@ exports.apply = async (yaml, { loadFile, relativeTo, cache = new Map() }) => {
 
     for (const entry of imports) {
 
-        const buffer = await internals.loadSource(entry.source, { loadFile, cache });
+        const buffer = await internals.loadSource(entry.source, { loadFile });
 
         const imported = Yaml.safeLoad(buffer, {
             schema: Yaml.FAILSAFE_SCHEMA,
             json: true
         });
 
-        await exports.apply(imported, { loadFile, relativeTo: entry, cache });
+        await exports.apply(imported, { loadFile, relativeTo: entry });
 
         delete imported.import;
 

test/fixtures/index.js

@@ -7,6 +7,7 @@ const SimpleGit = require('simple-git/promise');
 const Sinon = require('sinon');
 const Tmp = require('tmp');
 
+const Loader = require('../../lib/loader');
 const Utils = require('../../lib/utils');
 
 
@@ -28,6 +29,8 @@ module.exports = class TestContext {
 
     cleanup() {
 
+        Loader.clearCache();
+
         Sinon.restore();
 
         this._cleanup.forEach((cleanup) => cleanup());

test/travis.js

@@ -156,6 +156,11 @@ describe('.travis.yml parsing', () => {
                 resolved: { '14': '14.3.0' }
             }
         });
+
+        // verify cache returns the same result
+        const result2 = await NodeSupport.detect({ path: fixture.path });
+        internals.assertCommit(result2);
+        expect(result2).to.equal(result);
     });
 
     it('resolves and merges (prepend/append)', async () => {