similar to: [nbdkit PATCH] python: Make sure callbacks are actually callable

The tracebacks are compressed into a single line because we're using PyObject_Str, but they are just about usable if not very readable. For example you would see an error like this: nbdkit: error: ./python-exception.py: config_complete: error: ['Traceback (most recent call last):\n', ' File "./python-exception.py", line 54, in config_complete\n raise_error1()\n',

On 7/16/19 6:04 AM, Richard W.M. Jones wrote: > A Closure is a list of (usually one, but can be more) closures. In C > there is also a singe ‘void *user_data’ parameter which is passed by > the caller into the function and through as the first parameter of > each callback invocation. > > By grouping the previously separate Opaque and Callback* parameters > together we can

Inspection of the generated code showed several places where we did not release references on all error paths. In particular, switching things to always jump to an out: label, even when the underlying C function cannot fail, makes it easier to clean up when the user passes wrong types to a function call. One of the easiest triggers without this patch was this one-liner: $ nbdsh -c

On 8/13/19 10:12 AM, Richard W.M. Jones wrote: > An optional Closure parameter, but otherwise works the same way as > Closure. > --- > generator/generator | 57 ++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 46 insertions(+), 11 deletions(-) > > @@ -4394,6 +4399,16 @@ let print_python_binding name { args; optargs; ret; may_set_error } = > ) args; >

On 8/13/19 5:06 AM, Richard W.M. Jones wrote: > An optional Closure parameter, but otherwise works the same way as > Closure. > @@ -3778,6 +3777,7 @@ let generate_lib_api_c () = > ) args; > List.iter ( > function > + | OClosure { cbname } -> pr ", %s_callback ? \"<fun>\" : \"NULL\"" cbname Well, it also permits a

[RFC because generated OCaml code needs the same treatment, but I ran out of time to play with that. At least 'make -C python check' passes, although coverage is not complete yet, as there is no python/t/5XX-pread-structured-callback.py...] [Also RFC because I'm not sure if the use of a record type for 'callback' is the best approach or most idiomatic OCaml - but hey, it

Patch 2 certainly allows you to set the thread model. However patch 3 shows that if you set it to nbdkit.THREAD_MODEL_PARALLEL it will crash. If you look closely at the stack trace (attached below) you can see that ignoring threads which are in parts of nbdkit unrelated to Python: Thread 4: In pread, waiting in time.sleep(). This thread has released the GIL. Thread 2: Started to

On Wed, Aug 8, 2018 at 4:07 PM Richard W.M. Jones <rjones@redhat.com> wrote: > The tracebacks are compressed into a single line because we're using > PyObject_Str, but they are just about usable if not very readable. > For example you would see an error like this: > > nbdkit: error: ./python-exception.py: config_complete: error: ['Traceback > (most recent call

In preparation for adding other optional flag arguments to the python bindings, start by making the existing 'may_trim' flag to 'zero' be optional. That is, the plugin need not define the parameter if it does not make any semantic difference (ie. if the plugin ignores the hint and never trims); while if the parameter exists, we now pass it as a keyword argument rather than as a

Posting now that I got something to compile (at the expense of breaking OCaml bindings), but I'm open to ideas on how to improve it. Eric Blake (2): generator: Tweak print_c_arg_list to take alternate first arg RFC: generator: Handle shared callbacks in Python generator/generator | 556 ++++++++++++++++++++++---------------------- 1 file changed, 280 insertions(+), 276 deletions(-) --

In preparation for closure lifetimes, split up the Closure so it no longer describes a list of closures, but a single callback. This changes the API because functions which take 2 or more closures now pass a separate user_data for each one. --- docs/libnbd.pod | 3 +- examples/strict-structured-reads.c | 2 +- generator/generator | 760

h.nbd_connect_command was leaking a python object per parameter, and also leaks memory on failure. In fact, it was possible to segfault on something as trivial as: nbdsh -c 'h.connect_command(["true",1])' h.nbd_pread was leaking a read buffer on every single synchronous read. My previous patch to address closure callbacks had a bug in h.nbd_pread_structured and similar: if the

As mentioned in my reviews, I wonder if we should make our python callbacks look a bit more Pythonic by having kwargs added for each new flag that we want to expose. The idea was first floated here: https://www.redhat.com/archives/libguestfs/2018-April/msg00108.html Note that with my proposal, there is no need for a python script to expose a global API_VERSION variable; new flags are added

Basically the same as this patch series, but for Python: https://www.redhat.com/archives/libguestfs/2019-August/msg00235.html plus adding the 590 asynch test at the end. Rich.

As before, but this one has working Python bindings. OCaml still TBD. Rich.

On Fri, Nov 22, 2019 at 11:53 PM Nir Soffer <nsoffer@redhat.com> wrote: > > On Fri, Nov 22, 2019 at 11:35 PM Eric Blake <eblake@redhat.com> wrote: > > > > On 11/22/19 3:20 PM, Nir Soffer wrote: > > > > >>> +# There are several variants of the API. nbdkit will call this > > >>> +# function first to determine which one you want to

A Closure is a list of (usually one, but can be more) closures. In C there is also a singe ‘void *user_data’ parameter which is passed by the caller into the function and through as the first parameter of each callback invocation. By grouping the previously separate Opaque and Callback* parameters together we can avoid the awkward situation where we have to scan through the argument list to try

Fix some things I noticed while reviewing v1, and follow Rich's idea to add a new nbdkit_set_error() utility function with a binding for Python users to request a particular error (rather than being forced to live with whatever stale value is in errno after all the intermediate binding glue code). I could not easily find out how to register a C function callable from perl bindings, and have

In preparation for adding other optional flag arguments to the python bindings, start by making the existing 'may_trim' flag to 'zero' be optional. That is, the plugin need not define the parameter if it does not make any semantic difference (ie. if the plugin ignores the hint and never trims); while if the parameter exists, we now pass it as a keyword argument rather than as a

Patches 1-4 are basically uncontroversial, straightforward refactoring and IMHO we should just push them. Possibly 1-3 should be squashed together, but I posted them separately so they are easier to review. Patches 5 and 6 together implement OClosure. Patch 5 adds the feature and is simple to understand. Patch 6 changes the Closure completion callbacks into OClosure, but because it doesn't