Implement get_or_create_index method and add tests

Simple readme update

Author: eskombro

README.md

@@ -121,6 +121,8 @@ You can check out [the API documentation](https://docs.meilisearch.com/reference
 client.create_index('books')
 # Create an index and give the primary-key
 client.create_index('books', {'primaryKey': 'book_id'})
+# Get an index or create it if it doesn't exist
+client.get_or_create_index('books', {'primaryKey': 'book_id'})
 ```
 
 #### List all indexes <!-- omit in toc -->

meilisearch/client.py

@@ -1,6 +1,7 @@
 from meilisearch.index import Index
 from meilisearch.config import Config
 from meilisearch._httprequests import HttpRequests
+from meilisearch.errors import MeiliSearchApiError
 
 class Client():
     """
@@ -80,6 +81,34 @@ def get_index(self, uid):
         """
         return Index.get_index(self.config, uid=uid)
 
+    def get_or_create_index(self, uid, options=None):
+        """Get an index, or create it if it doesn't exist.
+
+        Parameters
+        ----------
+        uid: str
+            UID of the index
+        options: dict, optional
+            Options passed during index creation (ex: primaryKey)
+
+        Returns
+        -------
+        index : Index
+            an instance of Index containing the information of the retrieved or newly created index
+        Raises
+        ------
+        HTTPError
+            In case of any other error found here https://docs.meilisearch.com/references/#errors-status-code
+        """
+        try:
+            index = Index(self.config, uid)
+            index.create(self.config, uid, options)
+        except MeiliSearchApiError as err:
+            if err.message != 'index already exists':
+                raise err
+            index = self.get_index(uid)
+        return index
+
     def get_all_stats(self):
         """Get all stats of MeiliSearch
 

meilisearch/tests/index/test_index.py

@@ -10,6 +10,7 @@ class TestIndex:
     index_uid = 'indexUID'
     index_uid2 = 'indexUID2'
     index_uid3 = 'indexUID3'
+    index_uid4 = 'indexUID4'
 
     def setup_class(self):
         clear_all_indexes(self.client)
@@ -56,6 +57,32 @@ def test_get_index_with_none_uid(self):
         with pytest.raises(Exception):
             self.client.get_index(uid=None)
 
+    def test_get_or_create_index(self):
+        """Test get_or_create_index method"""
+        # self.client.create_index(self.index_uid3)
+        index_1 = self.client.get_or_create_index(self.index_uid4)
+        index_2 = self.client.get_or_create_index(self.index_uid4)
+        index_3 = self.client.get_or_create_index(self.index_uid4)
+        assert index_1.uid == index_2.uid == index_3.uid == self.index_uid4
+        update = index_1.add_documents([{
+            'book_id': 1,
+            'name': "Some book"
+        }])
+        index_1.wait_for_pending_update(update['updateId'])
+        documents = index_2.get_documents()
+        assert len(documents) == 1
+        index_2.delete()
+        with pytest.raises(Exception):
+            self.client.get_index(index_3).info()
+
+    def test_get_or_create_index_with_primary_key(self):
+        """Test get_or_create_index method with primary key"""
+        index_1 = self.client.get_or_create_index('books', {'primaryKey': self.index_uid4})
+        index_2 = self.client.get_or_create_index('books', {'primaryKey': 'some_wrong_key'})
+        assert index_1.get_primary_key() == self.index_uid4
+        assert index_2.get_primary_key() == self.index_uid4
+        index_1.delete()
+
     def test_index_info(self):
         """Tests getting an index's info"""
         index = self.client.get_index(uid=self.index_uid)