Edit File: Design.Plugins.txt
Plugins ======= Plugins in Dovecot are really simple. They basically have two functions: * <plugin_name>_init(module) is called when 'module_dir_init()' is called. * <plugin_name>_deinit() is called when 'module_dir_deinit()' or 'module_dir_unload()' is called. The <plugin_name> is the short version of the plugin name, based on the filename. For example if the filename is 'lib11_imap_quota_plugin.so', the <plugin_name> is "imap_quota" and the init function to be called is imap_quota_plugin_init(). Versioning ---------- Since different Dovecot versions can have different APIs, your plugin should usually also define<plugin_name>_version, like: ---%<------------------------------------------------------------------------- const char *imap_quota_plugin_version = DOVECOT_ABI_VERSION; ---%<------------------------------------------------------------------------- If the version string in plugin doesn't match the version of the running binary, the plugin loading fails. The DOVECOT_ABI_VERSION is defined in Dovecot's 'config.h', which you're typically including. Dependencies ------------ Some plugins depend on another one. In some systems (but not all) it's possible to handle this by giving a nicer error message than "symbol xyz not found". There are two steps for this: First create <plugin_name>_dependencies array listing plugin names that the plugin depends on, like: ---%<------------------------------------------------------------------------- const char *imap_quota_plugin_dependencies[] = { "quota", NULL }; ---%<------------------------------------------------------------------------- Then you'll also have to make the plugin .so binary link to the other plugins: ---%<------------------------------------------------------------------------- if PLUGIN_DEPS lib11_imap_quota_plugin_la_LIBADD = \ ../quota/lib10_quota_plugin.la endif ---%<------------------------------------------------------------------------- PLUGIN_DEPS is set only if plugin dependencies are actually supported. Otherwise the build might fail or plugin loading might fail. Once all this is done, trying to load imap_quota plugin without quota plugin gives a nice error message: ---%<------------------------------------------------------------------------- Error: Can't load plugin imap_quota_plugin: Plugin quota must be loaded also ---%<------------------------------------------------------------------------- (This file was created from the wiki on 2019-02-05 04:42)
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