session: api cleanup

[vpp.git] / src / vpp-api / python / vpp_papi / vpp_transport_shmem.py

diff --git a/src/vpp-api/python/vpp_papi/vpp_transport_shmem.py b/src/vpp-api/python/vpp_papi/vpp_transport_shmem.py
index 5920cd1..4719f23 100644 (file)
--- a/src/vpp-api/python/vpp_papi/vpp_transport_shmem.py
+++ b/src/vpp-api/python/vpp_papi/vpp_transport_shmem.py
@@ -2,10 +2,14 @@
 # A transport class. With two implementations.
 # One for socket and one for shared memory.
 #
+import logging
 
 from cffi import FFI
 import cffi
 
+logger = logging.getLogger('vpp_papi.transport')
+logger.addHandler(logging.NullHandler())
+
 ffi = FFI()
 ffi.cdef("""
 typedef void (*vac_callback_t)(unsigned char * data, int len);
@@ -24,12 +28,17 @@ int vac_msg_table_max_index(void);
 void vac_rx_suspend (void);
 void vac_rx_resume (void);
 void vac_set_error_handler(vac_error_callback_t);
- """)
+void vac_mem_init (size_t size);
+""")
 
 vpp_object = None
 
-# Barfs on failure, no need to check success.
-vpp_api = ffi.dlopen('libvppapiclient.so')
+# allow file to be imported so it can be mocked in tests.
+# If the shared library fails, VppTransport cannot be initialized.
+try:
+    vpp_api = ffi.dlopen('libvppapiclient.so')
+except OSError:
+    vpp_api = None
 
 
 @ffi.callback("void(unsigned char *, int)")
@@ -47,7 +56,19 @@ def vac_error_handler(arg, msg, msg_len):
     vpp_object.logger.warning("VPP API client:: %s", ffi.string(msg, msg_len))
 
 
-class VppTransport(object):
+class VppTransportShmemIOError(IOError):
+    """ exception communicating with vpp over shared memory """
+
+    def __init__(self, rv, descr):
+        self.rv = rv
+        self.desc = descr
+
+        super(VppTransportShmemIOError, self).__init__(rv, descr)
+
+
+class VppTransport:
+    VppTransportShmemIOError = VppTransportShmemIOError
+
     def __init__(self, parent, read_timeout, server_address):
         self.connected = False
         self.read_timeout = read_timeout
@@ -55,6 +76,8 @@ class VppTransport(object):
         global vpp_object
         vpp_object = parent
 
+        vpp_api.vac_mem_init(0)
+
         # Register error handler
         vpp_api.vac_set_error_handler(vac_error_handler)
 
@@ -71,7 +94,7 @@ class VppTransport(object):
         self.connected = True
         if not pfx:
             pfx = ffi.NULL
-        return vpp_api.vac_connect(name, pfx, msg_handler, rx_qlen)
+        return vpp_api.vac_connect(name.encode('ascii'), pfx, msg_handler, rx_qlen)
 
     def disconnect(self):
         self.connected = False
@@ -87,7 +110,7 @@ class VppTransport(object):
         return vac_callback_sync if not do_async else vac_callback_async
 
     def get_msg_index(self, name):
-        return vpp_api.vac_get_msg_index(name)
+        return vpp_api.vac_get_msg_index(name.encode('ascii'))
 
     def msg_table_max_index(self):
         return vpp_api.vac_msg_table_max_index()
@@ -95,23 +118,26 @@ class VppTransport(object):
     def _write_new_cffi(self, buf):
         """Send a binary-packed message to VPP."""
         if not self.connected:
-            raise IOError(1, 'Not connected')
+            raise VppTransportShmemIOError(1, 'Not connected')
         return vpp_api.vac_write(ffi.from_buffer(buf), len(buf))
 
     def _write_legacy_cffi(self, buf):
         """Send a binary-packed message to VPP."""
         if not self.connected:
-            raise IOError(1, 'Not connected')
+            raise VppTransportShmemIOError(1, 'Not connected')
         return vpp_api.vac_write(bytes(buf), len(buf))
 
-    def read(self):
+    def read(self, timeout=None):
         if not self.connected:
-            raise IOError(1, 'Not connected')
+            raise VppTransportShmemIOError(1, 'Not connected')
+        if timeout is None:
+            timeout = self.read_timeout
         mem = ffi.new("char **")
         size = ffi.new("int *")
-        rv = vpp_api.vac_read(mem, size, self.read_timeout)
+        rv = vpp_api.vac_read(mem, size, timeout)
         if rv:
-            raise IOError(rv, 'vac_read failed')
+            strerror = 'vac_read failed.  It is likely that VPP died.'
+            raise VppTransportShmemIOError(rv, strerror)
         msg = bytes(ffi.buffer(mem[0], size[0]))
         vpp_api.vac_free(mem[0])
         return msg