Pipeline DISCARD support (#1565)

closes #1539

Part of #1546

2 files changed, 33 insertions, 1 deletions

diff --git a/redis/client.py b/redis/client.py
index 8979280..7a022a0 100755
--- a/redis/client.py
+++ b/redis/client.py
@@ -1810,6 +1810,12 @@ class Pipeline(Redis):
         finally:
             self.reset()
 
+    def discard(self):
+        """Flushes all previously queued commands
+        See: https://redis.io/commands/DISCARD
+        """
+        self.execute_command("DISCARD")
+
     def watch(self, *names):
         "Watches the values at keys ``names``"
         if self.explicit_transaction:
diff --git a/tests/test_pipeline.py b/tests/test_pipeline.py
index 9bc4a9f..08bd40b 100644
--- a/tests/test_pipeline.py
+++ b/tests/test_pipeline.py
@@ -1,7 +1,7 @@
 import pytest
 
 import redis
-from .conftest import wait_for_command
+from .conftest import wait_for_command, skip_if_server_version_lt
 
 
 class TestPipeline:
@@ -353,3 +353,29 @@ class TestPipeline:
 
             assert pipe == pipe2
             assert response == [True, [0, 0, 15, 15, 14], b'1']
+
+    @skip_if_server_version_lt('2.0.0')
+    def test_pipeline_discard(self, r):
+
+        # empty pipeline should raise an error
+        with r.pipeline() as pipe:
+            pipe.set('key', 'someval')
+            pipe.discard()
+            with pytest.raises(redis.exceptions.ResponseError):
+                pipe.execute()
+
+        # setting a pipeline and discarding should do the same
+        with r.pipeline() as pipe:
+            pipe.set('key', 'someval')
+            pipe.set('someotherkey', 'val')
+            response = pipe.execute()
+            pipe.set('key', 'another value!')
+            pipe.discard()
+            pipe.set('key', 'another vae!')
+            with pytest.raises(redis.exceptions.ResponseError):
+                pipe.execute()
+
+            pipe.set('foo', 'bar')
+            response = pipe.execute()
+        assert response[0]
+        assert r.get('foo') == b'bar'