similar to: [PATCH nbdkit v2 00/10] Implement nbdkit API v2 for Python plugins.

And fill out most of the missing bits of the API. Rich.

v2 was here: https://www.redhat.com/archives/libguestfs/2019-November/msg00163.html I pushed patch 1 (with spelling fix), patch 4 and patch 5 since those were previously ACKed on the list. Differences in v3: - Add error checking to PyModule_AddIntConstant. - Use API_VERSION constant instead of function. - Add max API version supported to --dump-plugin output. - Print API_VERSION selected by

v3 was here: https://www.redhat.com/archives/libguestfs/2019-November/msg00209.html In v4: - Rebase on top of current master. Includes various fixes and updates required because of Nir's patches that went into master. - Fix api_version() -> API_VERSION in patch 2 noted previously on the mailing list. Rich.

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

First out of our four language bindings to add FUA support (for reference, I added 'zero' support for python, perl, and ruby back in 1.1.13, then Rich had to add it for ocaml in 1.1.20). I tested this heavily under python 2, but for now only compile tested under python 3; I plan to do further testing there and make any tweaks if necessary. I wrote patch 5 early on, but then realized I

When I added .can_FOO caching in 1.16, I missed the case that the sh plugin itself was calling .can_flush twice in some situations (in order to default .can_fua). Then right after, I regressed it to call .can_zero twice (in order to default .can_fast_zero). I also missed that .thread_model could use better caching, because at the time, I did not add testsuite coverage. Fix that now. Eric Blake

I noticed these while working on adding fua support into python, these are independent enough to push now (and I'll have to rebase my 'optional may_trim' patch on top of this). Eric Blake (2): python: Use Py_XDEFREF() python: Simplify calling into plugin plugins/python/python.c | 106 ++++++++---------------------------------------- 1 file changed, 18 insertions(+), 88

This picks up python and ocaml. Some of our languages are lacking a number of bindings (for example, lua and perl lack .extents, so I didn't have anything to copy from), and I felt less comfortable with golang and rust. But for python and ocaml, I was able to test a working implementation. Eric Blake (2): python: Implement .list_exports and friends ocaml: Implement .list_exports and

--- plugins/python/nbdkit-python-plugin.pod | 19 ++++++- plugins/python/python.c | 75 +++++++++++++++++++++++++ tests/test-python-plugin.py | 8 ++- tests/test_python.py | 73 +++++++++++++++++++++++- 4 files changed, 169 insertions(+), 6 deletions(-) diff --git a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod

On 3/18/20 8:21 PM, Eric Blake wrote: > In commit c306fa93ab and neighbors (v1.15.1), a concerted effort went > into caching the results of .can_FOO callbacks, with commit messages > demonstrating that a plugin with a slow callback should not have that > delay magnified multiple times. But nothing was added to the > testsuite at the time, and with the sh and eval plugins, we still

On Fri, Nov 22, 2019 at 9:55 PM Richard W.M. Jones <rjones@redhat.com> wrote: > > This tests the Python plugin thoroughly by issuing client commands > through libnbd and checking we get the expected results. > --- > tests/Makefile.am | 13 +-- > tests/test-python-plugin.py | 134 ++++++++++++++++++++++++++++ > tests/test-python.py | 172

I still don't have .prepare/.finalize working cleanly across reopen, but did find a nasty bug where a botched assertion means we failed to notice reads beyond EOF in both the xz and retry filter. Refactoring backend.c will make .finalize work easier. Eric Blake (5): xz: Avoid reading beyond EOF retry: Check size before transactions tests: Test retry when get_size values change

It's been several weeks since I posted v2 (I got distracted by improving libnbd to better test things, which in turn surfaced some major memory leak problems in nbdsh that are now fixed). Many of the patches are minor rebases from v2, with the biggest changes being fallout from: - patch 2: rename nbdkit_add_default_export to nbdkit_use_default_export - overall: this missed 1.22, so update

This is working for me now, although possibly only on Python 3.9. Dan suggested PyEval_InitThreads but that was deprecated in Python 3.7. Rich.

It's easy to use the sh script to demonstrate that nbdkit is inefficiently calling into .get_size, .can_fua, and friends more than necessary. We've also commented on the list in the past that it would be nice to ensure that when filters call into next_ops, they are not violating constraints (as we've have to fix several bugs in the past where we did not have such checking to protect

On 11/22/19 1:53 PM, Richard W.M. Jones wrote: > To avoid breaking existing plugins, Python plugins wishing to use > version 2 of the API must opt in by declaring: > > def api_version(): > return 2 > > (Plugins which do not do this are assumed to want API version 1). Could we also permit the python code to declare a global variable instead of a function? But a

I think this is my last round of patches for issues I identified with the retry filter. With this in place, it should be safe to interject another filter in between retry and the plugin. Eric Blake (5): retry: Don't call into closed plugin tests: Refactor test-retry-reopen-fail.sh tests: Enhance retry test to cover failed reopen server: Move prepare/finalize/close recursion to

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

On Wed, Apr 11, 2018 at 12:03:42AM -0500, Eric Blake wrote: > Now that we have FUA support, the C code can call can_fua as > frequently as on every write. If the python script has a > can_fua, we can avoid doubling the calls into python by > caching the per-connection results, done by wrapping the > python handle in a C struct. > > This commit is marked RFC because it might

v1 was here: https://www.redhat.com/archives/libguestfs/2020-February/msg00081.html v2 replaces struct connection *conn = GET_CONN; with GET_CONN; which sets conn implicitly and asserts that it is non-NULL. If we actually want to test if conn is non-NULL or behave differently, then you must use threadlocal_get_conn() instead, and some existing uses do that. Rich.