# Plugins Many aspects of VerneMQ can be extended using plugins. The standard VerneMQ package comes with several official plugins. You can show the enabled & running plugins via: ``` vmq-admin plugin show ``` The command above displays all the enabled plugins together with the hooks they implement: ``` +-----------+-----------+-----------------+-----------------------------+ | Plugin | Type | Hook(s) | M:F/A | +-----------+-----------+-----------------+-----------------------------+ |vmq_passwd |application|auth_on_register |vmq_passwd:auth_on_register/5| | vmq_acl |application| auth_on_publish | vmq_acl:auth_on_publish/6 | | | |auth_on_subscribe| vmq_acl:auth_on_subscribe/3 | +-----------+-----------+-----------------+-----------------------------+ ``` The table will show the following information: * name of the plugin * type (application or single module) * all the hooks implemented in the plugin * the exact module and function names (`M:F/A`) implementing those hooks. As an example on how to read the table: the `vmq_passwd:auth_on_register/5` function is the actual implementation of the `auth_on_register` hook in the `vmq_passwd` application plugin. In addition, you can conclude that the plugin is currently running, as it shows up in the table. To display information on internal plugins, add the `--internal` flag. The table below shows you that the generic metadata application and the generic message store are actually internal plugins. ``` $ sudo vmq-admin plugin show --internal +-----------------------+-------------+-------------------------------+------------------------------------------------+ | Plugin | Type | Hook(s) | M:F/A | +-----------------------+-------------+-------------------------------+------------------------------------------------+ | vmq_swc | application | metadata_put | vmq_swc_plugin:metadata_put/3 | | | | metadata_get | vmq_swc_plugin:metadata_get/2 | | | | metadata_delete | vmq_swc_plugin:metadata_delete/2 | | | | metadata_fold | vmq_swc_plugin:metadata_fold/3 | | | | metadata_subscribe | vmq_swc_plugin:metadata_subscribe/1 | | | | cluster_join | vmq_swc_plugin:cluster_join/1 | | | | cluster_leave | vmq_swc_plugin:cluster_leave/1 | | | | cluster_members | vmq_swc_plugin:cluster_members/0 | | | | cluster_rename_member | vmq_swc_plugin:cluster_rename_member/2 | | | | cluster_events_add_handler | vmq_swc_plugin:cluster_events_add_handler/2 | | | | cluster_events_delete_handler | vmq_swc_plugin:cluster_events_delete_handler/2 | | | | cluster_events_call_handler | vmq_swc_plugin:cluster_events_call_handler/3 | | | | | | +-----------------------+-------------+-------------------------------+------------------------------------------------+ | vmq_generic_msg_store | application | msg_store_write | vmq_generic_msg_store:msg_store_write/2 | | | | msg_store_delete | vmq_generic_msg_store:msg_store_delete/2 | | | | msg_store_find | vmq_generic_msg_store:msg_store_find/2 | | | | msg_store_read | vmq_generic_msg_store:msg_store_read/2 | | | | | | +-----------------------+-------------+-------------------------------+------------------------------------------------+ | vmq_config | module | change_config | vmq_config:change_config/1 | | | | | | +-----------------------+-------------+-------------------------------+------------------------------------------------+ | vmq_acl | application | change_config | vmq_acl:change_config/1 | | | | auth_on_publish | vmq_acl:auth_on_publish/6 | | | | auth_on_subscribe | vmq_acl:auth_on_subscribe/3 | | | | auth_on_publish_m5 | vmq_acl:auth_on_publish_m5/7 | | | | auth_on_subscribe_m5 | vmq_acl:auth_on_subscribe_m5/4 | | | | | | +-----------------------+-------------+-------------------------------+------------------------------------------------+ | vmq_passwd | application | change_config | vmq_passwd:change_config/1 | | | | auth_on_register | vmq_passwd:auth_on_register/5 | | | | auth_on_register_m5 | vmq_passwd:auth_on_register_m5/6 | | | | | | +-----------------------+-------------+-------------------------------+------------------------------------------------+ ``` ## Enable a plugin ``` vmq-admin plugin enable --name=vmq_acl ``` This enables the ACL plugin. Because the `vmq_acl` plugin is already started the above command won't succeed. In case the plugin sits in an external directory you must also to provide the `--path=PathToPlugin`. ## Disable a plugin ``` vmq-admin plugin disable --name=vmq_acl ``` ## Persisting Plugin Configurations and Starts To make a plugin start when VerneMQ boots, you need to tell VerneMQ in the main `vernemq.conf` file. The general syntax to enable a plugin is to add a line like `plugins.pluginname = on`. Using the `vmq_passwd` plugin as an example: ``` plugins.vmq_passwd = on ``` If the plugin is external (all your own VerneMQ plugin will be of this category), the path can be specified like this: ``` plugins.myplugin = on plugins.myplugin.path = /path/to/plugin ``` Plugin specific settings can be configured via `myplugin.somesetting = value`, like: ``` vmq_passwd.password_file = ./etc/vmq.passwd ``` Check the `vernemq.conf` file for additional details and examples. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.vernemq.com/master/configuring-vernemq/plugins.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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