generalize build_artifacts.py
diff --git a/tools/run_tests/artifact_targets.py b/tools/run_tests/artifact_targets.py
new file mode 100644
index 0000000..a34fa8e
--- /dev/null
+++ b/tools/run_tests/artifact_targets.py
@@ -0,0 +1,137 @@
+#!/usr/bin/env python
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Definition of targets to build artifacts."""
+
+import jobset
+
+
+def create_docker_jobspec(name, dockerfile_dir, shell_command, environ={},
+                   flake_retries=0, timeout_retries=0):
+  """Creates jobspec for a task running under docker."""
+  environ = environ.copy()
+  environ['RUN_COMMAND'] = shell_command
+
+  docker_args=[]
+  for k,v in environ.iteritems():
+    docker_args += ['-e', '%s=%s' % (k, v)]
+  docker_env = {'DOCKERFILE_DIR': dockerfile_dir,
+                'DOCKER_RUN_SCRIPT': 'tools/jenkins/docker_run.sh',
+                'OUTPUT_DIR': 'artifacts'}
+  jobspec = jobset.JobSpec(
+          cmdline=['tools/jenkins/build_and_run_docker.sh'] + docker_args,
+          environ=docker_env,
+          shortname='build_artifact.%s' % (name),
+          timeout_seconds=30*60,
+          flake_retries=flake_retries,
+          timeout_retries=timeout_retries)
+  return jobspec
+
+
+def create_jobspec(name, cmdline, environ=None, shell=False,
+                   flake_retries=0, timeout_retries=0):
+  """Creates jobspec."""
+  jobspec = jobset.JobSpec(
+          cmdline=cmdline,
+          environ=environ,
+          shortname='build_artifact.%s' % (name),
+          timeout_seconds=5*60,
+          flake_retries=flake_retries,
+          timeout_retries=timeout_retries,
+          shell=shell)
+  return jobspec
+
+
+def macos_arch_env(arch):
+  """Returns environ specifying -arch arguments for make."""
+  if arch == 'x86':
+    arch_arg = '-arch i386'
+  elif arch == 'x64':
+    arch_arg = '-arch x86_64'
+  else:
+    raise Exception('Unsupported arch')
+  return {'CFLAGS': arch_arg, 'LDFLAGS': arch_arg}
+
+
+class CSharpExtArtifact:
+  """Builds C# native extension library"""
+
+  def __init__(self, platform, arch):
+    self.name = 'csharp_ext_%s_%s' % (platform, arch)
+    self.platform = platform
+    self.arch = arch
+    self.labels = ['artifact', 'csharp', platform, arch]
+
+  def pre_build_jobspecs(self):
+    if self.platform == 'windows':
+      return [create_jobspec('prebuild_%s' % self.name,
+                             ['tools\\run_tests\\pre_build_c.bat'],
+                             shell=True,
+                             flake_retries=5,
+                             timeout_retries=2)]
+    else:
+      return []
+
+  def build_jobspec(self):
+    if self.platform == 'windows':
+      msbuild_platform = 'Win32' if self.arch == 'x86' else self.arch
+      return create_jobspec(self.name,
+                            ['tools\\run_tests\\build_artifact_csharp.bat',
+                             'vsprojects\\grpc_csharp_ext.sln',
+                             '/p:Configuration=Release',
+                             '/p:PlatformToolset=v120',
+                             '/p:Platform=%s' % msbuild_platform],
+                            shell=True)
+    else:
+      environ = {'CONFIG': 'opt',
+                 'EMBED_OPENSSL': 'true',
+                 'EMBED_ZLIB': 'true'}
+      if self.platform == 'linux':
+        return create_docker_jobspec(self.name,
+            'tools/dockerfile/grpc_artifact_linux_%s' % self.arch,
+            'tools/run_tests/build_artifact_csharp.sh')
+      else:
+        environ.update(macos_arch_env(self.arch))
+        return create_jobspec(self.name,
+                              ['tools/run_tests/build_artifact_csharp.sh'],
+                              environ=environ)
+
+  def __str__(self):
+    return self.name
+
+
+def targets():
+  """Gets list of supported targets"""
+  return [CSharpExtArtifact('linux', 'x86'),
+          CSharpExtArtifact('linux', 'x64'),
+          CSharpExtArtifact('macos', 'x86'),
+          CSharpExtArtifact('macos', 'x64'),
+          CSharpExtArtifact('windows', 'x86'),
+          CSharpExtArtifact('windows', 'x64')]