[RFR] Added latency DA

README.rst

@@ -35,10 +35,14 @@ Providing an extendable and easy to use tool for developers and QE to ensure the
 Features
 --------
 
-* Async all the things via asyncio and asyncssh
+- Async all the things via asyncio and asyncssh
 
-* Easy disruptive scenarios definitions via yaml files
+- Easy disruptive scenarios definitions via yaml files
 
-* Tail remote log files and search for regular expressions
+- Tail remote log files and search for regular expressions
 
-* Event driven disruptive actions trigger
+- Event driven disruptive actions trigger
+
+  - Service restart
+
+  - Inject network latency

disruption_generator/experiments/latency-example.yaml

@@ -0,0 +1,14 @@
+---
+- disrupt_action:
+    - name: Restart sysstat on regex ocurrance
+      listener:
+        re: FINISH
+        log: /var/log/vdsm/vdsm.log
+        host: localhost
+      trigger:
+        - action:
+            name: latency
+            params: 100ms
+            target_host: localhost
+            wait: 3
+            timeout: 10

disruption_generator/trigger/trigger.py

@@ -1,8 +1,8 @@
+import asyncio
+import asyncssh
 import logging
 
-from asyncssh import SSHClient, create_connection
-
-ALL_ACTIONS = ["restart_service"]
+ALL_ACTIONS = ["restart_service", "latency"]
 
 logger = logging.getLogger(__name__)
 
@@ -41,6 +41,31 @@ async def run_client(self, cmd):
                 return False
 
     async def restart_service(self):
+        """
+        Restart a service on a remote host
+
+        Returns:
+            result (bool): Result of the restart
+        """
         cmd = "systemctl restart"
         result = await self.run_client(cmd)
         return result
+
+    async def latency(self):
+        """
+        Add latency to a remote hosts link
+
+        Returns:
+            result (bool): True if successful, False otherwise
+        """
+        cmd_add = "tc qdisc add dev eth0 root netem delay"
+        cmd_del = "tc qdisc del dev eth0 root netem delay"
+        result = await self.run_client(cmd_add)
+        wait = self.action.wait if self.action.wait else 10
+        await asyncio.sleep(wait)
+        if result:
+            rollback = await self.run_client(cmd_del)
+            if not rollback:
+                logger.info("Rollback was not successful")
+
+        return result