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mirror of https://github.com/openvswitch/ovs synced 2025-08-28 12:58:00 +00:00

409 Commits

Author SHA1 Message Date
Paul Boca
42e22f951d python tests: Fixed abs_file_name function for Windows
On windows a path containint ':' is considered an absolute path.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:57:47 -07:00
Paul Boca
8ac6d39624 python tests: Fixed OSError not iterable on Windows
On Windows if this exception is triggered then it will raise an exception while in the
exception handler.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:56:24 -07:00
Paul Boca
93c43dc0dc python tests: Added fcntl module for Windows
This is needed for lockf function used to lock the PID file on Windows.
ioctl and fcntl functions are not implemented at this time because they are
not used by any script.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:42:47 -07:00
Paul Boca
03693b2f54 python tests: Fixed ctl file name for Windows
On Windows the CTL filename doesn't contain the pid of the process.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:34:16 -07:00
Paul Boca
8229f855fc python tests: Register signal handlers only on supported types on Windows
SIGHUP and SIGALRM are not available on Windows.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:31:57 -07:00
Paul Boca
36d516346a python tests: Implemented signal.alarm for Windows
signal.alarm is not available in Windows and would trigger an exception
when called. Implemented this to mentain compatibility between
Windows and Linux for python tests.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
2016-08-03 08:23:39 -07:00
Numan Siddique
a7261bf7ac python: Send old values of the updated cols in notify for update2
When python IDL calls the "notify" function after processing the "update2"
message from ovsdb-server, it is suppose to send the old values of the
updated columns as the last parameter. But the recent commit "897c8064"
sends the updated values. This breaks the behaviour.
This patch fixes this issue. It also updates the description of
the 'updates' param of the notify function to make it more clear.

Fixes: 897c8064 ("python: move Python idl to work with monitor_cond")
Signed-off-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-07-27 14:49:07 -07:00
Terry Wilson
622749d8a3 python: Serial JSON via Python's json lib.
There is no particularly good reason to use our own Python JSON
serialization implementation when serialization can be done faster
with Python's built-in JSON library.

A few tests were changed due to Python's default JSON library
returning slightly more precise floating point numbers.

Signed-off-by: Terry Wilson <twilson@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-07-26 09:17:13 -07:00
Zong Kai LI
38c4437843 python: add set type for ovs.idl.data.Datum.from_python
ovs.db.idl.Datum.from_python fails to handle set type value, while set
type is also a common iterable sequence, just like list and tuple.
No reason IDL caller must to turn set type parameters to list or tuple
type. Otherwise, they will fail to insert data, but get no exception.

Reported-at: https://bugs.launchpad.net/networking-ovn/+bug/1605573
Signed-off-by: Zong Kai LI <zealokii@gmail.com>
Acked-by: Richard Theis <rtheis@us.ibm.com>
Tested-by: Richard Theis <rtheis@us.ibm.com>
Signed-off-by: Russell Bryant <russell@ovn.org>
2016-07-25 10:40:44 -04:00
Terry Wilson
ee89ea7b47 json: Move from lib to include/openvswitch.
To easily allow both in- and out-of-tree building of the Python
wrapper for the OVS JSON parser (e.g. w/ pip), move json.h to
include/openvswitch. This also requires moving lib/{hmap,shash}.h.

Both hmap.h and shash.h were #include-ing "util.h" even though the
headers themselves did not use anything from there, but rather from
include/openvswitch/util.h. Fixing that required including util.h
in several C files mostly due to OVS_NOT_REACHED and things like
xmalloc.

Signed-off-by: Terry Wilson <twilson@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-07-22 17:09:17 -07:00
Liran Schour
16ebb90e05 lib: add monitor_cond_change API to C IDL lib
Add to IDL API that allows the user to add and remove clauses on a table's condition
iteratively. IDL maintain tables condition and send monitor_cond_change to the server
upon condition change.
Add tests for conditional monitoring to IDL.

Signed-off-by: Liran Schour <lirans@il.ibm.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-07-18 22:58:45 -07:00
Liran Schour
897c8064f5 python: move Python idl to work with monitor_cond
Python idl works now with "monitor_cond" method. Add test
for backward compatibility with old "monitor" method.

Signed-off-by: Liran Schour <lirans@il.ibm.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-07-18 22:58:45 -07:00
Daniele Di Proietto
cc51a9677e vlog.py: Remove redundant setLevel() if "/dev/log" doesn't exist.
Also update a comment.

Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: Gurucharan Shetty <guru@ovn.org>
2016-07-06 16:52:28 -07:00
Paul Boca
902f916318 vlog test: Disable default syslog logger
Disable the syslog logger in case on Windows, '/dev/log' doesn't exist.
Seems like on Python34 a default handler is added to the logger and it prints
even if no handler is set by us.

Signed-off-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>
2016-07-06 15:17:03 -07:00
Terry Wilson
c63b04d678 Add optional C extension wrapper for Python JSON parsing
The pure Python in-tree JSON parser is *much* slower than the
in-tree C JSON parser. A local test parsing a 100Mb JSON file
showed the Python version taking 270 seconds. With the C wrapper,
it took under 4 seconds.

The C extension will be used automatically if it can be built. If
the extension fails to build, a warning is displayed and the build
is restarted without the extension.

The Serializer class is replaced with Python's built-in
JSON library since the ability to process chunked data is not
needed in that case.

The extension should work with both Python 2.7 and Python 3.3+.

Signed-off-by: Terry Wilson <twilson@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-06-08 11:35:17 -07:00
Terry Wilson
2c362f17d6 Ensure significand remains an integer in Python3 json parser
The / operation in Python 2 is "floor division" for int/long types
while in Python 3 is "true division". This means that the
significand can become a float with the existing code in Python 3.
This, in turn, can result in a parse of something like [1.10e1]
returning 11 in Python 2 and 11.0 in Python 3. Switching to the
// operator resolves this difference.

The JSON tests do not catch this difference because the built-in
serializer prints floats with the %.15g format which will convert
floats with no fractional part to an integer representation.

Signed-off-by: Terry Wilson <twilson@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-06-08 11:35:03 -07:00
Ofer Ben-Yacov
af35823711 python: Add TCP passive-mode to IDL.
Requested-by: "D M, Vikas" <vikas.d-m@hpe.com>
Requested-by: "Kamat, Maruti Haridas" <maruti.kamat@hpe.com>
Requested-by: "Sukhdev Kapur" <sukhdev@arista.com>
Requested-by: "Migliaccio, Armando" <armando.migliaccio@hpe.com>
Signed-off-by: "Ofer Ben-Yacov" <ofer.benyacov@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2016-05-20 08:10:53 -07:00
Russell Bryant
28b4f69ba2 python: Update Python version checks.
Instead of checking the raw version, use the six.PY2 and six.PY3 helpers
to determine if Python 2 or Python 3 are in use.

In one case, the check was to determine if the Python version was >=
2.6.  We now only support >= 2.7, so this check would always be true.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
Acked-by: Miguel Angel Ajo <majopela@redhat.com>
2016-04-15 16:52:50 -04:00
Ben Pfaff
3df3584256 ovsdb: Force columns that contain weak references to be immutable.
An immutable weak reference is a hole in the constraint system: if
referenced rows are deleted, then the weak reference needs to change.
Therefore, force columsn that contain weak references to be mutable.

Reported-by: "Elluru, Krishna Mohan" <elluru.kri.mohan@hpe.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Ryan Moats <rmoats@us.ibm.com>
2016-04-11 21:02:26 -07:00
Russell Bryant
99c8be3ee4 NEWS: Claim support for Python 3.
Also update the Python ovs package info to note that both Python 2 and 3
are supported.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-22 15:18:03 -05:00
Ben Pfaff
063801288e vlog: Add vlog/close command.
Requested-by: P R Dinesh
Requested-at: https://github.com/openvswitch/ovs/pull/94
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Russell Bryant <russell@ovn.org>
2016-02-10 13:36:04 -08:00
Russell Bryant
0e7c46c440 python: Deal with str and byte differences.
Python 3 has separate types for strings and bytes.  Python 2 used the
same type for both.  We need to convert strings to bytes before writing
them out to a socket.  We also need to convert data read from the socket
to a string.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:43:35 -05:00
Russell Bryant
fbafc3c263 python: Fix object comparisons in Python 3.
Python 3 no longer supports __cmp__.  Instead, we have to implement the
"rich comparison" operators.  We implement __eq__ and __lt__ and use
functools.total_ordering to implement the rest.

In one case, no __cmp__ method was provided and instead relied on the
default behavior provided in Python 2.  We have to implement the
comparisons explicitly for Python 3.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:42:32 -05:00
Russell Bryant
c03afda69a python: Don't compare None and int.
Comparing None to an integer worked in Python 2, but fails in Python 3.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:42:21 -05:00
Russell Bryant
da2d45c6c6 python: Remove reamining direct type comparisons.
I've hit several bugs in this Python 3 work where the fix was some code
needed to be converted to use isinstance().  This has been primarily
around deadling with the changes to unicode handling.  Go ahead and
convert the rest of the direct type comparisons to use isinstance(), as
it could avoid a bug I haven't hit yet and it's more Pythonic, anyway.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:42:10 -05:00
Russell Bryant
eac25f500a python: Use six.unichr().
six.unichr() is equivalent to unichr() in Python 2
and chr() in Python 3.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:42:03 -05:00
Russell Bryant
d36bbd37f6 python: Drop use of sys.maxint.
sys.maxint does not exist in Python 3, as an int does not have a max
value anymore (except as limited by implementation details and system
resources).

sys.maxsize works as a reasonable substitute as it's the same as
sys.maxint.  The Python 3.0 release notes have this to say:

  The sys.maxint constant was removed, since there is no longer a limit
  to the value of integers. However, sys.maxsize can be used as an
  integer larger than any practical list or string index. It conforms to
  the implementation’s “natural” integer size and is typically the same
  as sys.maxint in previous releases on the same platform (assuming the
  same build options).

sys.maxsize is documented as:

  An integer giving the maximum value a variable of type Py_ssize_t can
  take. It’s usually 2**31 - 1 on a 32-bit platform and 2**63 - 1 on a
  64-bit platform.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:41:30 -05:00
Russell Bryant
981e9560ce python: Don't use StringIO directly.
StringIO.StringIO in Python 2 became io.StringIO in Python 3.  Use
six.StringIO which is an alias for the two cases.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:41:21 -05:00
Russell Bryant
58de9fc30e python: Drop use of types.FunctionType.
This code asserted that the callback argument was of type
types.FunctionType.  It's more pythonic to just check that the argument
is callable, and not specifically that it's a function.  There are other
ways to implement a callback than types.FunctionType.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:41:11 -05:00
Russell Bryant
1ccbf95c6e python: Drop use of types.StringTypes.
types.StringTypes does not exist in Python 3.  We can use
six.string_types, instead.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:41:01 -05:00
Russell Bryant
25f599fbd3 python: Drop unicode type.
Python 2 had str and unicode.  Python 3 only has str, which is always a
unicode string.  Drop use of unicode with the help of six.text_type
(unicode in py2 and str in py3) and six.string_types ([str, unicode] in
py2 and [str] in py3).

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:40:49 -05:00
Russell Bryant
8f808842a0 python: Drop usage of long type.
Python 2 has both long and int types.  Python 3 only has int, which
behaves like long.

In the case of needing a set of integer types, we can use
six.integer_types which includes int and long for Python 2 and just int
for Python 3.

We can convert all cases of long(value) to int(value), because as of
Python 2.4, when the result of an operation would be too big for an int,
the type is automatically converted to a long.

There were several places in this patch doing type comparisons.  The
preferred way to do this is using the isinstance() or issubclass()
built-in functions, so I converted the similar checks nearby while I was
at it.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-02-02 16:40:36 -05:00
Russell Bryant
cb96c1b27e python: Convert dict iterators.
In Python 2, dict.items(), dict.keys(), and dict.values() returned a
list.  dict.iteritems(), dict.iterkeys(), and dict.itervalues() returned
an iterator.

As of Python 3, dict.iteritems(), dict.itervalues(), and dict.iterkeys()
are gone.  items(), keys(), and values() now return an iterator.

In the case where we want an iterator, we now use the six.iter*()
helpers.  If we want a list, we explicitly create a list from the
iterator.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-21 23:00:11 -05:00
Russell Bryant
b3ac29477d python: Stop using xrange().
Python 2 had range() and xrange().  xrange() is more efficient, but
behaves differently so range() was retained for compatibility.  Python 3
only has range() and it behaves like Python 2's xrange().

Remove explicit use of xrange() and use six.moves.range() to
make sure we're using xrange() from Python 2 or range() from Python 3.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-20 16:43:54 -05:00
Russell Bryant
73eb682edb python: Fix xmlrpclib imports.
Fix imports of xmlrpclib to be compatible with Python 3.  Python 2 had
xmlrpclib (client) and SimpleXMLRPCServer (server).  In Python 3, these
have been renamed to xmlrpc.client and xmlrpc.server.

The solution implemented here is to use the six library.  It may seem
excessive for this particular issue, but the six library provides
helpers for Python 2 and 3 compatibility for many different issues.
This is just the first of many uses of the six library.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-20 16:43:15 -05:00
Russell Bryant
8ea171aba0 python: Fix print function compatibility.
The print statement from Python 2 is a function in Python 3.  Enable
print function support for Python 2 and convert print statements to
function calls.

Enable the H233 flake8 warning.  If the hacking plugin is installed,
this will generate warnings for print statement usage not compatible
with Python 3.

  H233 Python 3.x incompatible use of print operator

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-12 11:47:33 -05:00
Russell Bryant
66d61c90a7 python: Stop use of tuple parameter unpacking
Python 3 removed support for tuple parameter unpacking.

https://www.python.org/dev/peps/pep-3113/

Instead of:

    def foo((a, b)):
        print(a)
        print(b)

you should do:

    def foo(a_b):
        a, b = a_b
        print(a)
        print(b)

but in both uses here, the values were never used so the fix is even
simpler.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-12 11:47:33 -05:00
Terry Wilson
3ab76c56d8 python: Start fixing some Python 3 issues.
This patch fixes just the Python 3 problems found by running:

  python3 setup.py install

There are still many other issues to be fixed, but this is a start.

Signed-off-by: Terry Wilson <twilson@redhat.com>
[russell@ovn.org resolved conflicts with current master]
Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-12 11:47:33 -05:00
Numan Siddique
e9ad921999 python: Fix the TypeError exception seen when idl.Idl parses lock reply
File "/usr/lib/python2.7/site-packages/ovs/db/idl.py", line 334,
in __parse_lock_notify
  self.__update_has_lock(self, new_has_lock)
TypeError: __update_has_lock() takes exactly 2 arguments (3 given)

Signed-off-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>
2016-01-08 09:54:47 -05:00
Russell Bryant
37520ab386 python: Restrict line length to 79 chars.
Resolve pep8 error:

  E501 line too long (80 > 79 characters)

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 20:19:20 -05:00
Russell Bryant
eda26d40ae python: Resolve some indentation warnings.
This patch resolves the following warnings from flake8:

 E111 indentation is not a multiple of four
 E112 expected an indented block
 E113 unexpected indentation

It's critical to have correct indentation in Python code, so it seemed
worth enabling these warnings.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:18:21 -05:00
Russell Bryant
f7f7fcced5 python: Add missing Apache License headers.
Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:17:56 -05:00
Russell Bryant
0ab00d6d74 python: Inherit from object.
class Vlog now inherits from "object".  This is a "new style" Python
class, which isn't new at all at this point.  This was introduced back
in Python 2.2, and some Python 2 code won't work as expected without it.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:17:56 -05:00
Russell Bryant
a0631d92d9 python: Fix several pep8 whitespace errors.
Fix the following pep8 errors:

  E201 whitespace after '('
  E203 whitespace before ','
  E222 multiple spaces after operator
  E225 missing whitespace around operator
  E226 missing whitespace around arithmetic operator
  E231 missing whitespace after ':'
  E241 multiple spaces after ':'
  E251 unexpected spaces around keyword / parameter equals
  E261 at least two spaces before inline comment
  E262 inline comment should start with '# '
  E265 block comment should start with '# '
  E271 multiple spaces after keyword

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:16:20 -05:00
Russell Bryant
3c057118d1 python: Resolve pep8 comparison errors.
Resolve pep8 errors:

  E711 comparison to None should be 'if cond is None:'

The reason comparing against None with "is None" is preferred over
"== None" is because a class can define its own equality operator and
produce bizarre unexpected behavior.  Using "is None" has a very
explicit meaning that can not be overridden.

  E721 do not compare types, use 'isinstance()'

This one is actually a mistake by the tool in most cases.
'from ovs.db import types' looks just like types from the Python stdlib.
In those cases, use the full ovs.db.types name.  Fix one case where it
actually was types from the stdlib.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:13:47 -05:00
Russell Bryant
bdca6c4b56 python: Resolve pep8 blank line errors.
Resolve pep8 errors E302 and E303:

  E302 expected 2 blank lines, found 1
  E303 too many blank lines (3)

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:13:47 -05:00
Russell Bryant
e8049bc5e8 python: Fix invalid varable/function references.
This code referred to "rows" where it meant to refer to "fetched_rows".
The patch resolves flake8 error:

  F821 undefined name 'rows'

python/build/nroff.py used a function fatal() that was not defined,
which raised the same type of error.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:13:47 -05:00
Russell Bryant
5697ca9901 python: Remove unused imports and variables.
This resolves the following flake8 error types:

  F841 local variable 'e' is assigned to but never used
  F401 'exceptions' imported but unused

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:13:47 -05:00
Russell Bryant
115d8719db python: Run flake8 at build time.
If flake8 is installed, run it at build time.  Similar to most Makefile
targets, run it once and then only run again if the files change.

flake8 is set to ignore all error and warning types that currently occur.
Future patches will remove items from the ignore list as they are
resolved.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
2016-01-05 18:13:46 -05:00
Shad Ansari
80c12152f3 ovsdb-idl: Support for readonly columns that are fetched on-demand
There is currently no mechanism in IDL to fetch specific column values
on-demand without having to register them for monitoring. In the case
where the column represent a frequently changing entity (e.g. counter),
and the reads are relatively infrequent (e.g. CLI client), there is a
significant overhead in replication.

This patch adds support in the Python IDL to register a subset of the
columns of a table as "readonly". Readonly columns are not replicated.
Users may "fetch" the readonly columns of a row on-demand. Once fetched,
the columns are not updated until the next fetch by the user. Writes by
the user to readonly columns does not change the value (both locally or
on the server).

The two main user visible changes in this patch are:
  - The SchemaHelper.register_columns() method now takes an optionaly
    argument to specify the subset of readonly column(s)
  - A new Row.fetch(columns) method to fetch values of readonly columns(s)

Usage:
------

    # Schema file includes all columns, including readonly
    schema_helper = ovs.db.idl.SchemaHelper(schema_file)

    # Register interest in columns with 'r' and 's' as readonly
    schema_helper.register_columns("simple", [i, r, s], [r, s])

    # Create Idl and jsonrpc, and wait for update, as usual
    ...

    # Fetch value of column 'r' for a specific row
    row.fetch('r')
    txn.commit_block()

    print row.r
    print getattr(row, 'r')

    # Writing to readonly column has no effect (locally or on server)
    row.r = 3
    print row.r     # prints fetched value not 3

Signed-off-by: Shad Ansari <shad.ansari@hp.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2015-11-23 08:34:54 -08:00