Introduce upper constraints

This is a global setting that will apply across every project, a
constraint on the versions of things that can be installed via pip.

This is a first pass, adding basic functionality, by allowing a single
constraint URL to be provided. Future iterations of this feature may be
tied to a "superrepo" that contains all the projects _and_ the
constraints for those projects all in one place.

Change-Id: Ib5c2dd441b9294b775e755e595486a671d8de57f

giftwrap/builders/__init__.py

@@ -16,6 +16,7 @@
 
 import logging
 import os
+import requests
 import threading
 
 from giftwrap.gerrit import GerritReview
@@ -36,6 +37,7 @@ class Builder(object):
         self._temp_src_dir = None
         self._spec = spec
         self._thread_exit = []
+        self._constraints = None
 
     @staticmethod
     def builder_names(ext_mgr=None):
@@ -55,6 +57,27 @@ class Builder(object):
                         "Error was: %s", e)
             return []
 
+    def _get_upper_constraints(self):
+        try:
+            curl = self._spec.settings.upper_constraints
+            response = requests.get(curl)
+
+            if response.status_code != 200:
+                raise Exception("Unable to get constraints at %s. Error: %d" %
+                                (curl, response.status_code))
+
+            constraints = response.text.encode('utf-8')
+
+            cfile = os.path.join(self._temp_src_dir, 'constraints.txt')
+
+            with open(cfile, 'w') as f:
+                f.write(constraints)
+
+            return cfile
+
+        except Exception as e:
+            raise Exception("Unable to construct constraints. Error: %s" % e)
+
     def _build_project(self, project):
         try:
             self._prepare_project_build(project)
@@ -81,6 +104,9 @@ class Builder(object):
             if self._spec.settings.include_config:
                 self._copy_sample_config(src_clone_dir, project)
 
+            if self._spec.settings.upper_constraints:
+                self._constraints = self._get_upper_constraints()
+
             self._install_project(project.install_path, src_clone_dir)
 
             if project.postinstall_dependencies:

giftwrap/builders/docker_builder.py

@@ -84,8 +84,11 @@ class DockerBuilder(Builder):
 
     def _install_pip_dependencies(self, venv_path, dependencies):
         pip_path = self._get_venv_pip_path(venv_path)
+        install = "install"
+        if self._constraints:
+            install += " -c %s" % self._constraints
         for dependency in dependencies:
-            self._execute("%s install %s" % (pip_path, dependency))
+            self._execute("%s %s %s" % (pip_path, install, dependency))
 
     def _copy_sample_config(self, src_clone_dir, project):
         src_config = os.path.join(src_clone_dir, 'etc')
@@ -96,7 +99,10 @@ class DockerBuilder(Builder):
 
     def _install_project(self, venv_path, src_clone_dir):
         pip_path = self._get_venv_pip_path(venv_path)
-        self._execute("%s install %s" % (pip_path, src_clone_dir))
+        install = "install"
+        if self._constraints:
+            install += " -c %s" % self._constraints
+        self._execute("%s %s %s" % (pip_path, install, src_clone_dir))
 
     def _finalize_project_build(self, project):
         self._commands.append("rm -rf %s" % self._temp_dir)

giftwrap/builders/package_builder.py

@@ -70,8 +70,11 @@ class PackageBuilder(Builder):
 
     def _install_pip_dependencies(self, venv_path, dependencies):
         pip_path = self._get_venv_pip_path(venv_path)
+        install = "install"
+        if self._constraints:
+            install += " -c %s" % self._constraints
         for dependency in dependencies:
-            self._execute("%s install %s" % (pip_path, dependency))
+            self._execute("%s %s %s" % (pip_path, install, dependency))
 
     def _copy_sample_config(self, src_clone_dir, project):
         src_config = os.path.join(src_clone_dir, 'etc')
@@ -87,7 +90,10 @@ class PackageBuilder(Builder):
 
     def _install_project(self, venv_path, src_clone_dir):
         pip_path = self._get_venv_pip_path(venv_path)
-        self._execute("%s install %s" % (pip_path, src_clone_dir))
+        install = "install"
+        if self._constraints:
+            install += " -c %s" % self._constraints
+        self._execute("%s %s %s" % (pip_path, install, src_clone_dir))
 
     def _finalize_project_build(self, project):
         # build the package

giftwrap/settings.py

@@ -31,7 +31,7 @@ class Settings(object):
                  package_name_format=None, version=None,
                  base_path=None, install_path=None, gerrit_dependencies=True,
                  force_overwrite=False, output_dir=None, include_config=True,
-                 parallel_build=True):
+                 parallel_build=True, upper_constraints=None):
         if not version:
             raise Exception("'version' is a required settings")
         self.build_type = build_type
@@ -44,6 +44,7 @@ class Settings(object):
         self._output_dir = output_dir
         self.include_config = include_config
         self.parallel_build = parallel_build
+        self.upper_constraints = upper_constraints
 
     @property
     def package_name_format(self):