libvirt interface

2 files changed, 105 insertions, 0 deletions

diff --git a/src_py/hatter/__init__.py b/src_py/hatter/__init__.py
deleted file mode 100644
index e69de29..0000000
--- a/src_py/hatter/__init__.py
+++ /dev/null
diff --git a/src_py/hatter/vm.py b/src_py/hatter/vm.py
new file mode 100644
index 0000000..87e71b9
--- /dev/null
+++ b/src_py/hatter/vm.py
@@ -0,0 +1,105 @@
+import time
+import libvirt
+
+
+class VM:
+
+    def __init__(self, domain_name, uri='qemu:///system', snapshot_name=None,
+                 temp_snapshot_name='temp_hatter', address_retry_count=10,
+                 address_delay=5):
+        self._domain_name = domain_name
+        self._uri = uri
+        self._snapshot_name = snapshot_name
+        self._temp_snapshot_name = temp_snapshot_name
+        self._address_retry_count = address_retry_count
+        self._address_delay = address_delay
+        self._conn = None
+        self._domain = None
+        self._temp_snapshot = None
+        self._address = None
+
+    @property
+    def address(self):
+        return self._address
+
+    def start(self):
+        try:
+            self._conn = _libvirt_connect(self._uri)
+            self._domain = _libvirt_get_domain(self._conn, self._domain_name)
+            if self._domain.isActive():
+                self._domain.destroy()
+            self._temp_snapshot = _libvirt_create_temp_snapshot(
+                self._domain, self._temp_snapshot_name)
+            if self._snapshot_name:
+                _libvirt_revert_snapshot(self._domain, self._snapshot_name)
+            _libvirt_start_domain(self._domain)
+            for _ in range(self._address_retry_count):
+                self._address = _libvirt_get_address(self._domain)
+                if self._address:
+                    return
+                time.sleep(self._address_delay)
+            raise Exception('ip addess not detected')
+        except Exception:
+            self.stop()
+            raise
+
+    def stop(self):
+        if self._domain:
+            self._domain.destroy()
+        if self._domain and self._temp_snapshot:
+            self._domain.revertToSnapshot(self._temp_snapshot)
+        if self._temp_snapshot:
+            self._temp_snapshot.delete()
+        if self._conn:
+            self._conn.close()
+        self._temp_snapshot = None
+        self._domain = None
+        self._conn = None
+        self._address = None
+
+
+def _libvirt_connect(uri):
+    conn = libvirt.open(uri)
+    if not conn:
+        raise Exception('could not open connection to {}'.format(uri))
+    return conn
+
+
+def _libvirt_get_domain(conn, domain_name):
+    domain = conn.lookupByName(domain_name)
+    if not domain:
+        raise Exception('domain {} not available'.format(domain_name))
+    return domain
+
+
+def _libvirt_start_domain(domain):
+    if domain.create():
+        raise Exception('could not run vm')
+
+
+def _libvirt_create_temp_snapshot(domain, temp_snapshot_name):
+    temp_snapshot = domain.snapshotLookupByName(temp_snapshot_name)
+    if temp_snapshot:
+        temp_snapshot.delete()
+    temp_snapshot = domain.snapshotCreateXML(
+        "<domainsnapshot><name>{}</name></domainsnapshot>".format(
+            temp_snapshot_name))
+    if not temp_snapshot:
+        raise Exception('could not create snapshot {}'.format(
+            temp_snapshot_name))
+    return temp_snapshot
+
+
+def _libvirt_revert_snapshot(domain, snapshot_name):
+    snapshot = domain.snapshotLookupByName(snapshot_name)
+    if not snapshot:
+        raise Exception('snapshot {} not available'.format(snapshot_name))
+    if domain.revertToSnapshot(snapshot):
+        raise Exception('could not revert snapshot {}'.format(snapshot_name))
+
+
+def _libvirt_get_address(domain):
+    addresses = domain.interfaceAddresses(0)
+    for i in addresses.values():
+        for j in i.get('addrs', []):
+            return j.get('addr')