Merge pull request #545 from remind101/threaded-tail

Implement --tail with threads

stacker/plan.py

@@ -2,7 +2,7 @@
 import logging
 import time
 import uuid
-import multiprocessing
+import threading
 
 from .util import stack_template_key_name
 from .exceptions import (
@@ -65,20 +65,21 @@ def run(self):
         skipped.
         """
 
+        stop_watcher = threading.Event()
         watcher = None
         if self.watch_func:
-            watcher = multiprocessing.Process(
+            watcher = threading.Thread(
                 target=self.watch_func,
-                args=(self.stack,)
+                args=(self.stack, stop_watcher)
             )
             watcher.start()
 
         try:
             while not self.done:
                 self._run_once()
         finally:
-            if watcher and watcher.is_alive():
-                watcher.terminate()
+            if watcher:
+                stop_watcher.set()
                 watcher.join()
         return self.ok
 

stacker/providers/aws/default.py

@@ -514,7 +514,7 @@ def is_stack_rolling_back(self, stack, **kwargs):
     def is_stack_failed(self, stack, **kwargs):
         return self.get_stack_status(stack) in self.FAILED_STATUSES
 
-    def tail_stack(self, stack, retries=0, **kwargs):
+    def tail_stack(self, stack, cancel, retries=0, **kwargs):
         def log_func(e):
             event_args = [e['ResourceStatus'], e['ResourceType'],
                           e.get('ResourceStatusReason', None)]
@@ -528,14 +528,15 @@ def log_func(e):
 
         try:
             self.tail(stack.fqn,
+                      cancel=cancel,
                       log_func=log_func,
                       include_initial=False)
         except botocore.exceptions.ClientError as e:
             if "does not exist" in e.message and retries < MAX_TAIL_RETRIES:
                 # stack might be in the process of launching, wait for a second
                 # and try again
                 time.sleep(1)
-                self.tail_stack(stack, retries=retries + 1, **kwargs)
+                self.tail_stack(stack, cancel, retries=retries + 1, **kwargs)
             else:
                 raise
 
@@ -565,7 +566,7 @@ def get_events(self, stackname):
             time.sleep(1)
         return reversed(sum(event_list, []))
 
-    def tail(self, stack_name, log_func=_tail_print, sleep_time=5,
+    def tail(self, stack_name, cancel, log_func=_tail_print, sleep_time=5,
              include_initial=True):
         """Show and then tail the event log"""
         # First dump the full list of events in chronological order and keep
@@ -584,7 +585,8 @@ def tail(self, stack_name, log_func=_tail_print, sleep_time=5,
                 if e['EventId'] not in seen:
                     log_func(e)
                     seen.add(e['EventId'])
-            time.sleep(sleep_time)
+            if cancel.wait(sleep_time):
+                return
 
     def destroy_stack(self, stack, **kwargs):
         logger.debug("Destroying stack: %s" % (self.get_stack_name(stack)))

tests/suite.bats

@@ -779,3 +779,34 @@ EOF
   assert_has_line "${STACKER_NAMESPACE}-vpc2: submitted (creating new stack)"
   assert_has_line "${STACKER_NAMESPACE}-vpc2: complete (creating new stack)"
 }
+
+@test "stacker build - tailing" {
+  needs_aws
+
+  config() {
+    cat <<EOF
+namespace: ${STACKER_NAMESPACE}
+stacks:
+  - name: vpc
+    class_path: stacker.tests.fixtures.mock_blueprints.Dummy
+  - name: bastion
+    class_path: stacker.tests.fixtures.mock_blueprints.Dummy
+    requires: [vpc]
+EOF
+  }
+
+  teardown() {
+    stacker destroy --force <(config)
+  }
+
+  # Create the new stacks.
+  stacker build --tail <(config)
+  assert "$status" -eq 0
+  assert_has_line "Using default AWS provider mode"
+  assert_has_line "Tailing stack: ${STACKER_NAMESPACE}-vpc"
+  assert_has_line "${STACKER_NAMESPACE}-vpc: submitted (creating new stack)"
+  assert_has_line "${STACKER_NAMESPACE}-vpc: complete (creating new stack)"
+  assert_has_line "Tailing stack: ${STACKER_NAMESPACE}-bastion"
+  assert_has_line "${STACKER_NAMESPACE}-bastion: submitted (creating new stack)"
+  assert_has_line "${STACKER_NAMESPACE}-bastion: complete (creating new stack)"
+}