Add simple depends_on API.

recipe_engine/run.py

Index: recipe_engine/run.py
diff --git a/recipe_engine/run.py b/recipe_engine/run.py
index 6949ee70212269c415831ca60fb64b10cbd630e9..03e8d21f2f1716f9e24cd30f4e3e49e2d9898442 100644
--- a/recipe_engine/run.py
+++ b/recipe_engine/run.py
@@ -72,6 +72,7 @@ import os
 import re
 import subprocess
 import sys
+import tempfile
 import threading
 import traceback
 
@@ -433,7 +434,7 @@ def run_steps(properties,
     'TESTING_SLAVENAME' in os.environ)):
     properties['use_mirror'] = False
 
-  engine = RecipeEngine(stream, properties, test_data)
+  engine = RecipeEngine(stream, properties, test_data, universe)
 
   # Create all API modules and top level RunSteps function.  It doesn't launch
   # any recipe code yet; RunSteps needs to be called.
@@ -750,16 +751,21 @@ class RecipeEngine(object):
     * step - uses engine.create_step(...).
 
   """
-  def __init__(self, stream, properties, test_data):
+  def __init__(self, stream, properties, test_data, universe):
     self._stream = stream
     self._properties = properties
     self._test_data = test_data
     self._step_history = collections.OrderedDict()
+    self._universe = universe
 
     self._previous_step_annotation = None
     self._previous_step_result = None
     self._api = None
 
+  def clone(self, stream=None, properties=None, universe=None):
+    return RecipeEngine(stream or self._stream, properties or self._properties,
+                        self._test_data, universe or self._universe)
+
   @property
   def properties(self):
     return self._properties
@@ -861,11 +867,12 @@ class RecipeEngine(object):
 
       raise exc(step['name'], step_result)
 
-
   def run(self, recipe_script, api):
     """Run a recipe represented by a recipe_script object.
 
     This function blocks until recipe finishes.
+    It mainly executes the recipe, and has some exception handling logic, and
+    adds the step history to the result.
 
     Args:
       recipe_script: The recipe to run, as represented by a RecipeScript object.
@@ -940,4 +947,21 @@ class RecipeEngine(object):
     """
     return step.as_jsonish()
 
+  def depend_on(self, recipe, properties, distributor=None):
+    if self._test_data.enabled:
+      # TODO(martiniss) test properties against the recipe
+      return self._test_data.depend_on_data[recipe][1]

[Paweł Hajdan Jr., 2015/11/13 12:30:00]

It's not obvious to me why [1] is needed at the end. What's going on here?

[martiniss, 2015/11/13 23:19:03]

Changed.

+    elif True: # is_local

[Paweł Hajdan Jr., 2015/11/13 12:30:00]

nit: "elif True" looks weird. Why not "else" with a TODO?

Actually with "return" above "else" shouldn't be needed and you could just
deindent the entire block.

[martiniss, 2015/11/13 23:19:03]

Dedented, and added a todo to add DM stuff.

+      recipes_py_loc = os.path.join(
+          self._universe.package_deps._context.repo_root, 'recipes.py')
+
+      with tempfile.NamedTemporaryFile() as f:
+        cmd = ['python', recipes_py_loc,

[Sergiy Byelozyorov, 2015/11/13 13:14:55]

please use sys.executable here

[martiniss, 2015/11/13 23:19:03]

Fixed.

+               '--package=%s' % self._universe._config_file, 'run',
+               '--result-file=%s' % f.name, recipe]
+        cmd.extend(['%s=%s' % (k, v) for k, v in properties.iteritems()])
+
+        rval = subprocess.call(cmd)

[Sergiy Byelozyorov, 2015/11/13 13:14:55]

So currently this would run recipe engine with another recipe locally and block
caller? Please consider adding a comment explaining that and also explain what
this will do in DM world.

+        return json.load(f)

[Sergiy Byelozyorov, 2015/11/13 13:14:55]

I wonder if we should also return rval here... perhaps by adding it to the
resulting dict, e.g. something along

result = json.load(f)
result['recipe_return_code'] = rval
return result

[martiniss, 2015/11/13 23:19:03]

I talked to estaab, and we agreed that what depend_on returns is not just the
result, but also a status_code of some kind. Not exactly sure what this will
look like, but this will change at some point. Shouldn't ignore the return code
I imagine.

[Sergiy Byelozyorov, 2015/11/17 11:19:40]

Please add a TODO if you are planning to make changes here later.

+