feat: add new mixin loadCustomLoader in Loader (#202)

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##### Checklist
<!-- Remove items that do not apply. For completed items, change [ ] to [x]. -->

- [x] `npm test` passes
- [x] tests and/or benchmarks are included
- [x] documentation is changed or added
- [x] commit message follows commit guidelines

##### Affected core subsystem(s)
<!-- Provide affected core subsystem(s). -->


##### Description of change
<!-- Provide a description of the change below this comment. -->

.gitignore

@@ -9,3 +9,4 @@ test/fixtures/egg/node_modules/egg-core
 .idea
 .nyc_output
 package-lock.json
+run

lib/loader/egg_loader.js

@@ -465,6 +465,7 @@ const loaders = [
   require('./mixin/middleware'),
   require('./mixin/controller'),
   require('./mixin/router'),
+  require('./mixin/custom_loader'),
 ];
 
 for (const loader of loaders) {

lib/loader/mixin/custom_loader.js

@@ -0,0 +1,53 @@
+'use strict';
+
+const assert = require('assert');
+const path = require('path');
+
+module.exports = {
+  loadCustomLoader() {
+    const loader = this;
+    assert(loader.config, 'should loadConfig first');
+    const customLoader = loader.config.customLoader || {};
+
+    for (const property of Object.keys(customLoader)) {
+      const loaderConfig = Object.assign({}, customLoader[property]);
+      assert(loaderConfig.directory, `directory is required for config.customLoader.${property}`);
+
+      let directory;
+      if (loaderConfig.loadunit === true) {
+        directory = this.getLoadUnits().map(unit => path.join(unit.path, loaderConfig.directory));
+      } else {
+        directory = path.join(loader.appInfo.baseDir, loaderConfig.directory);
+      }
+      // don't override directory
+      delete loaderConfig.directory;
+
+      const inject = loaderConfig.inject || 'app';
+      // don't override inject
+      delete loaderConfig.inject;
+
+      switch (inject) {
+        case 'ctx': {
+          const defaultConfig = {
+            caseStyle: 'lower',
+            fieldClass: `${property}Classes`,
+          };
+          loader.loadToContext(directory, property, Object.assign(defaultConfig, loaderConfig));
+          break;
+        }
+        case 'app': {
+          const defaultConfig = {
+            caseStyle: 'lower',
+            initializer(Class) {
+              return new Class(loader.app);
+            },
+          };
+          loader.loadToApp(directory, property, Object.assign(defaultConfig, loaderConfig));
+          break;
+        }
+        default:
+          throw new Error('inject only support app or ctx');
+      }
+    }
+  },
+};

test/fixtures/custom-loader/app/adapter/docker.js

@@ -0,0 +1,14 @@
+'use strict';
+
+class DockerAdapter {
+  constructor(app) {
+    this.app = app;
+  }
+
+  async inspectDocker() {
+    return this.app.config.customLoader.adapter;
+  }
+
+}
+
+module.exports = DockerAdapter;

test/fixtures/custom-loader/app/controller/user.js

@@ -0,0 +1,17 @@
+'use strict';
+
+class UserController {
+  constructor(ctx) {
+    this.ctx = ctx;
+    this.app = ctx.app;
+  }
+
+  async get() {
+    this.ctx.body = {
+      adapter: await this.app.adapter.docker.inspectDocker(),
+      repository: await this.ctx.repository.user.get(),
+    };
+  }
+}
+
+module.exports = UserController;

test/fixtures/custom-loader/app/plugin/a.js

@@ -0,0 +1,9 @@
+'use strict';
+
+class PluginA {
+  getName() {
+    return 'plugina';
+  }
+}
+
+module.exports = PluginA;

test/fixtures/custom-loader/app/repository/user.js

@@ -0,0 +1,14 @@
+'use strict';
+
+class UserRepository {
+  constructor(ctx) {
+    this.ctx = ctx;
+  }
+
+  async get() {
+    return this.ctx.params.name;
+  }
+
+}
+
+module.exports = UserRepository;

test/fixtures/custom-loader/app/router.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = app => {
+  app.router.get('/users/:name', app.controller.user.get);
+};

test/fixtures/custom-loader/config/b/app/plugin/b.js

@@ -0,0 +1,9 @@
+'use strict';
+
+class PluginB {
+  getName() {
+    return 'pluginb';
+  }
+}
+
+module.exports = PluginB;

test/fixtures/custom-loader/config/b/package.json

@@ -0,0 +1,5 @@
+{
+  "eggPlugin": {
+    "name": "b"
+  }
+}

test/fixtures/custom-loader/config/config.default.js

@@ -0,0 +1,19 @@
+'use strict';
+
+module.exports = {
+  customLoader: {
+    adapter: {
+      directory: 'app/adapter',
+      inject: 'app',
+    },
+    repository: {
+      directory: 'app/repository',
+      inject: 'ctx',
+    },
+    plugin: {
+      directory: 'app/plugin',
+      inject: 'app',
+      loadunit: true,
+    },
+  },
+};

test/fixtures/custom-loader/config/plugin.js

@@ -0,0 +1,8 @@
+'use strict';
+
+const path = require('path');
+
+exports.b = {
+  enable: true,
+  path: path.join(__dirname, 'b'),
+};

test/fixtures/custom-loader/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "custom-loader"
+}

test/loader/mixin/load_custom_loader.test.js

@@ -0,0 +1,95 @@
+'use strict';
+
+const assert = require('assert');
+const request = require('supertest');
+const utils = require('../../utils');
+
+describe('test/loader/mixin/load_custom_loader.test.js', function() {
+  let app;
+  before(function() {
+    app = utils.createApp('custom-loader');
+    app.loader.loadPlugin();
+    app.loader.loadConfig();
+    app.loader.loadController();
+    app.loader.loadRouter();
+    app.loader.loadCustomLoader();
+  });
+  after(() => app.close());
+
+  it('should load to app', async () => {
+    const res = await app.adapter.docker.inspectDocker();
+    assert(res);
+    assert(res.inject === 'app');
+  });
+
+  it('should load to ctx', async () => {
+    await request(app.callback())
+      .get('/users/popomore')
+      .expect({
+        adapter: {
+          directory: 'app/adapter',
+          inject: 'app',
+        },
+        repository: 'popomore',
+      })
+      .expect(200);
+  });
+
+  it('should support loadunit', async () => {
+    let name = app.plugin.a.getName();
+    assert(name === 'plugina');
+    name = app.plugin.b.getName();
+    assert(name === 'pluginb');
+  });
+
+
+  it('should loadConfig first', () => {
+    const app = utils.createApp('custom-loader');
+    try {
+      app.loader.loadCustomLoader();
+      throw new Error('should not run');
+    } catch (err) {
+      assert(err.message === 'should loadConfig first');
+    } finally {
+      app.close();
+    }
+  });
+
+  it('support set directory', () => {
+    const app = utils.createApp('custom-loader');
+    try {
+      app.loader.config = {
+        customLoader: {
+          custom: {
+          },
+        },
+      };
+      app.loader.loadCustomLoader();
+      throw new Error('should not run');
+    } catch (err) {
+      assert(err.message === 'directory is required for config.customLoader.custom');
+    } finally {
+      app.close();
+    }
+  });
+
+  it('inject support app/ctx', () => {
+    const app = utils.createApp('custom-loader');
+    try {
+      app.loader.config = {
+        customLoader: {
+          custom: {
+            directory: 'a',
+            inject: 'unknown',
+          },
+        },
+      };
+      app.loader.loadCustomLoader();
+      throw new Error('should not run');
+    } catch (err) {
+      assert(err.message === 'inject only support app or ctx');
+    } finally {
+      app.close();
+    }
+  });
+});