Document how to write MVT plugins

The custom modules page now leads with plugin packages. Loading module
files with --load-module and MVT_CUSTOM_MODULES moves to a section on
developing a module locally.

A new "Writing a module" section shows a module which subclasses
IOSExtraction. It lists each base class, the command pair it serves and the
helpers it provides. "Depending on a built-in module" says to import a
built-in class from its family package.

"Importing from MVT" says what mvt.plugin exports and what importing from
it means. The custom commands page shows a Command subclass which lists its
own modules. The sysdiagnose and plugin configuration pages import from
mvt.plugin.
This commit is contained in:
Donncha Ó Cearbhaill
2026-08-26 22:14:37 +02:00
parent da33c2fdb3
commit 1cf82f44e9
4 changed files with 253 additions and 77 deletions
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@@ -1,30 +1,32 @@
# Check an iOS Sysdiagnose
`mvt-ios check-sysdiagnose` prepares an iOS sysdiagnose archive for analysis by
custom MVT modules. MVT does not include built-in sysdiagnose modules. You must
load at least one custom module that explicitly supports this command.
custom MVT modules. MVT does not include built-in sysdiagnose modules. The
command runs the modules of the installed
[plugin packages](../development/index.md#installed-module-packages) which
declare support for it. Install at least one such package first.
The command accepts either an extracted sysdiagnose directory or the original
gzip-compressed tar archive.
```bash
mvt-ios check-sysdiagnose \
--load-module ./sysdiagnose_modules.py \
--output ./results \
mvt-ios check-sysdiagnose --output ./results \
./sysdiagnose_2024.01.02_03-04-05+0200.tar.gz
```
Use `--hashes` to include hashes for analyzed files in `info.json`, and
`--list-modules` to display the eligible custom modules without running them.
`--list-modules` to display the eligible modules without running them.
## Writing a custom module
Extend `SysdiagnoseExtraction` to access the archive contents consistently for
both directory and tar inputs. Each module must declare the command explicitly
in `supported_commands`.
Extend `SysdiagnoseExtraction` from `mvt.plugin`, see
[Writing a module](../development/index.md#writing-a-module). The module reads
the archive the same way whether MVT was given a folder or a tar archive. It
declares the command in `supported_commands`. While writing one,
[load it from its file](../development/index.md#developing-modules-locally).
```python
from mvt.ios.modules.sysdiagnose import SysdiagnoseExtraction
from mvt.plugin import SysdiagnoseExtraction
class ExampleSysdiagnoseModule(SysdiagnoseExtraction):
@@ -44,7 +46,9 @@ class ExampleSysdiagnoseModule(SysdiagnoseExtraction):
return None
```
The base class provides `from_sysdiagnose_folder()` and
`from_sysdiagnose_tar()` setup hooks, as well as protected file lookup, file
reading, and timezone extraction helpers. IPS crash-report metadata is exposed
on `ips_files`.
MVT extracts a tar archive first. It calls `from_sysdiagnose_folder()` on each
module before `run()`. `ips_files` lists the IPS crash reports.
`_get_files_by_pattern()` and `_get_file_content()` are internal helpers of the
base class. Use them to read the archive. Their names and signatures can change
between releases. See `src/mvt/ios/modules/sysdiagnose/base.py`.