similar to: [nbdkit PATCH 0/5] Implement .default_export, nbdkit_string_intern

This is a revision of my .default_export work, plus new work on .export_descriptions and a new exportname filter. I think it is now ready to check in. Things I'd still like in 1.22: - the file plugin should implement .list_exports (patch already posted, but it needs rebasing on this series) - the ext2 filter should override .list_exports when in exportname mode - the nbd plugin should be

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

I'm about to add an 'exportname' filter, and in the process, I noticed a few shortcomings in our API. Time to fix those before the 1.22 release locks our API in stone. First, .list_exports needs to know if it is pre- or post-TLS, as that may affect which names are exported. Next, overloading .list_exports to do both NBD_OPT_LIST and mapping "" to a canonical name is

Since v1: - patch 1: check size limits - patch 2: better handling of default export name canonicalization - patch 3: support filters as well as plugins - patch 4: new - patch 5: rewrite sh parser, fix testsuite to actually work and cover more cases (now that libnbd.git is fixed) Eric Blake (4): server: Add exports list functions server: Prepare to use export list from plugin log: Add

This takes Rich's API proposal and starts fleshing it out with enough meat that I was able to test 'nbdkit eval' advertising multiple exports with descriptions paired with 'qemu-nbd --list'. Eric Blake (3): server: Add exports list functions server: Prepare to use export list from plugin sh, eval: Add .list_exports support Richard W.M. Jones (1): server: Implement

Here's changes to the file plugin (which I'm happy with) and a new exportname filter (which is still at RFC stage; I need to finish implementing strict mode in .open, and add tests). I also discovered that we really want .list_exports and .open to know when they are used on plaintext vs. tls clients for --tls=on, and we may want to split out a new .default_export callback rather than

On Wed, Aug 26, 2020 at 09:16:46PM -0500, Eric Blake wrote: > Rather than defaulting .list_exports to blindly returning "", it is > nicer to have it reflect the result of .default_export. Meanwhile, > language bindings will have a C callback for both .list_exports and > .default_export, even if the underlying script does not, which means > any logic in plugins.c for

If you're following nbdkit development upstream you'll have seen that we are still making changes to the .list_exports and related APIs. The current .list_exports API upstream is not how it will look finally. The latest set of proposals was here: https://www.redhat.com/archives/libguestfs/2020-August/thread.html#00330 At the same time I'd like to do an nbdkit 1.22 (stable) release.

On Mon, Aug 24, 2020 at 05:02:56PM -0500, Eric Blake wrote: > On 8/24/20 7:52 AM, Eric Blake wrote: > >I'm about to add an 'exportname' filter, and in the process, I > >noticed a few shortcomings in our API. Time to fix those before > >the 1.22 release locks our API in stone. First, .list_exports > >needs to know if it is pre- or post-TLS, as that may

Patch 3 still needs tests added, but it is at least working from my simple command line tests. Eric Blake (3): server: Implement nbdkit_is_tls for use during .open server: Expose final thread_model to filter's .get_ready tlsdummy: New filter docs/nbdkit-filter.pod | 21 +- docs/nbdkit-plugin.pod | 34 ++- docs/nbdkit-tls.pod

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

Applies on top of my pending series for the exportname filter, addressing one of the todo's in that cover letter. Eric Blake (2): filters: Add .export_description wrappers ext2: Supply .list_exports and .default_export filters/ext2/nbdkit-ext2-filter.pod | 3 +- tests/Makefile.am | 16 +++- filters/ext2/ext2.c | 125 +++++++++++++++++++---------

Updated proposal, taking into account the default export. Instead of adding a second call, I made a couple of changes to list_exports: (1) If the plugin has a concept of a default export, it should add it as the first element in the exports list. (2) There is a new default_only flag which tells the plugin that the client is trying to request the name of the default export, so the

I'm about to add an 'exportname' filter, and in the process, I noticed a few shortcomings in our API. Time to fix those before the 1.22 release locks our API in stone. Overloading .list_exports in order to determine a canonical export name at .open time is awkward; the two uses (answering NBD_OPT_LIST for a full list, vs. remapping a client's "" into a canonical name

Another series on top of my exportname filter, marking off another todo bullet point. With this, you can now use the NBD plugin as a transparent passthrough of all export names served by the remote server in both directions (list advertisement server to client, and export name from client to server). Eric Blake (3): nbd: Implement .default_export, .export_description nbd: Add

On Tue, Aug 25, 2020 at 06:16:17AM -0500, Eric Blake wrote: > On 8/25/20 5:00 AM, Richard W.M. Jones wrote: > > >>>+=head2 C<.default_export> > >>>+ > >>>+ const char *default_export (int readonly, int is_tls); > >> > >>Oh fun. For some plugins (like ondemand), this is trivial: return a > >>compile-time constant string.

This creates filesystems on demand. A client simply connects with a desired export name and a new export is created. The export is persistent (until deleted by the server admin), and clients may disconnect and reconnect. In some respects this is similar to the nbdkit-tmpdisk-plugin, or nbdkit-file-plugin with the dir= option. --- plugins/ondemand/nbdkit-ondemand-plugin.pod | 190 ++++++

On 7/22/20 4:02 AM, Richard W.M. Jones wrote: >> The more I think about it, the more I disagree with disabling this. >> Or, put another way, I think that the _only_ time -e makes sense is >> _when_ you are using --run. Consider: >> >> nbdkit -U - -e foo info --run 'nbdsh -u $uri -c "print(h.pread(3, 0))"' >> nbdkit -U - -e bar info --run

On 7/21/20 12:46 PM, Eric Blake wrote: >> (2) The --run option no longer sets $exportname (to -e) nor puts the >>      export name into the $uri.  However this was always the wrong >>      thing to do since export names are per connection, not per server. >>      Existing --run scripts will see $exportname expand to "" which is >>      most likely what they

On Sat, Aug 15, 2020 at 03:41:39PM -0500, Eric Blake wrote: > On 8/14/20 12:20 PM, Richard W.M. Jones wrote: > >+Similar plugins include L<nbdkit-file-plugin(1)> which can serve a > >+predefined set of exports (clients cannot create more), > > Hmm - I wonder if it is worth a filter that runs a script any time > an .open fails. That script could send email to an