feat: 2.0 (#2406)

.github/2.0/cookbooks/CleanCode.md

@@ -0,0 +1,84 @@
+# Temporary Cookbook on Clean Code
+
+Jina is designed as a lean and efficient framework. Solutions built on top of Jina also mean to be so. Here are some
+tips to help you write clean & beautiful code.
+
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+1. `from jina import Document, DocumentArray, Executor, Flow, requests` is all you need. Copy-paste it as the first line of your code.
+
+1. No need to implement `__init__` if your `Executor` does not contain initial states.
+
+   ✅ Do:
+   ```python
+   from jina import Executor
+
+   class MyExecutor(Executor):
+      def foo(self, **kwargs):
+        ...
+   ```
+   😔 Don't:
+   ```python
+   from jina import Executor
+
+   class MyExecutor(Executor):
+      def __init__(**kwargs):
+        super().__init__(**kwargs)
+
+      def foo(self, **kwargs):
+        ...
+   ```
+
+1. Use `@requests` without specifying `on=` if your function mean to work on all requests. You can use it for catching all requests that are not for this Executor.
+
+   ✅ Do:
+   ```python
+   from jina import Executor, requests
+
+   class MyExecutor(Executor):
+
+      @requests
+      def _skip_all(self, **kwargs):
+        pass
+   ```
+   😔 Don't:
+   ```python
+   from jina import Executor
+
+   class MyExecutor(Executor):
+      @requests(on='/index')
+      def _skip_index(self, **kwargs):
+        pass
+
+      @requests(on='/search')
+      def _skip_search(self, **kwargs):
+        pass
+   ```
+
+1. Fold unnecessary arguments into `**kwargs`, only get what you need.
+
+   ✅ Do:
+   ```python
+   from jina import Executor, requests
+
+   class MyExecutor(Executor):
+
+      @requests
+      def foo_need_pars_only(self, parameters, **kwargs):
+        print(parameters)
+   ```
+   😔 Don't:
+   ```python
+   from jina import Executor, requests
+
+   class MyExecutor(Executor):
+
+      @requests
+      def foo_need_pars_only(self, docs, parameters, docs_matrix, groundtruths_matrix, **kwargs):
+        print(parameters)
+   ```