[Sheepdog] [RFC PATCH 3/4] tests: add Sheepdog cluster emulation library

[MORITA Kazutaka]

This python script supports:

 - create a virtual Sheepdog cluster with any number of nodes on
   localhost
 - start/stop sheep daemons on the virtual cluster
 - run collie commands on the virtual cluster
 - emulate read/write requests from VMs on the virtual cluster

Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
---
 tests/sheepdog_test.py |  135 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 135 insertions(+), 0 deletions(-)
 create mode 100644 tests/sheepdog_test.py

diff --git a/tests/sheepdog_test.py b/tests/sheepdog_test.py
new file mode 100644
index 0000000..111e7e2
--- /dev/null
+++ b/tests/sheepdog_test.py
@@ -0,0 +1,135 @@
+#
+# Copyright (C) 2011 Nippon Telegraph and Telephone Corporation.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version
+# 2 as published by the Free Software Foundation.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+from subprocess import *
+import os
+import re
+
+sheep_path = os.environ.get('SHEEP')
+collie_path = os.environ.get('COLLIE')
+
+
+class VirtualMachine:
+    def __init__(self, node, vdi):
+        self.node = node
+        self.vdi = vdi
+
+    def read(self, offset, size):
+        """Emulate read requests."""
+        vdiname = 'sheepdog:localhost:' + str(node.get_port()) + ':' + vdi.name
+        p = Popen(['qemu-io', vdiname, 'read', str(offset), str(size)], stdout=PIPE)
+        return p
+
+    def write(self, offset, size):
+        """Emulate write requests."""
+        vdiname = 'sheepdog:localhost:' + str(node.get_port()) + ':' + vdi.name
+        p = Popen(['qemu-io', vdiname, 'write', str(offset), str(size)], stdout=PIPE)
+        return p
+
+
+class VirtualDiskImage:
+    def __init__(self, name, size):
+        self.name = name
+        self.size = size
+        self.p = Popen([collie_path, 'vdi', 'create', name, str(size)], stdout=PIPE)
+
+    def wait(self):
+        """Wait until this vdi is created."""
+        self.p.wait()
+
+    def destroy(self):
+        p = Popen([collie_path, 'vdi', 'delete', self.name], stdout=PIPE)
+        return p
+
+
+class Node:
+    seq_nr = 0
+
+    def __init__(self):
+        self.idx = Node.seq_nr
+        Node.seq_nr = Node.seq_nr + 1
+
+        self.started = False
+        self.p = None
+
+    def __del__(self):
+        self.stop()
+
+    def get_port(self):
+        return 7000 + self.idx
+
+    def get_zone(self):
+        return 10000 + self.idx
+
+    def start(self):
+        """Run a sheep daemon on this node."""
+        if self.p and self.p.poll() == None:
+            return
+
+        self.p = Popen([sheep_path, '-f', '-d', '-p', str(self.get_port()),
+                        str(self.idx), '-z', str(self.get_zone())],
+                       stdout=PIPE, stderr=PIPE)
+
+    def wait(self):
+        """Wait until this node joins Sheepdog."""
+        if self.started:
+            return
+
+        while True:
+            line = self.p.stderr.readline()
+            if not line:
+                break
+            match = re.search(r'join Sheepdog cluster', line)
+            if match:
+                self.started = True
+                break
+
+    def stop(self):
+        """Stop the sheep daemon on this node."""
+        if self.p != None:
+            self.p.terminate()
+            self.p = None
+
+        self.started = False
+
+    def create_vm(self, vdi):
+        """Create a VM instance on this node."""
+        if self.p is None:
+            return None
+
+        return VirtualMachine(self, vdi)
+
+    def run_collie(self, cmd):
+        """Run administration commands on this node."""
+        if self.p is None:
+            return None
+
+        p = Popen([collie_path + ' ' + cmd + ' -p ' + str(self.get_port())],
+                  shell=True, stdout=PIPE)
+        return p
+
+
+class Sheepdog:
+    def __init__(self, nr_nodes = 3):
+        """Create a virtual Shepdog cluster with 'nr_nodes' nodes."""
+        self.nodes = [Node() for _ in range(nr_nodes)]
+
+    def create_vdi(self, name, size):
+        return VirtualDiskImage(name, size)
+
+    def format(self, node = None):
+        """Format Sheepdog cluster."""
+        if node is None:
+            node = self.nodes[0]
+
+        p = Popen([collie_path + ' cluster format -p ' + str(node.get_port())],
+                  shell=True, stdout=PIPE)
+        return p
-- 
1.7.2.5