symbols

Documentation

Overview

Package symbols provides prebuilt implementations for all the C symbols required to develop plugins as for the definitions of plugin_types.h.

This package defines low-level constructs for plugin development meant for advanced users that wish to use only a portion of the SDK internals. The sdk/plugins package should normally be used instead for the most general use cases, as it provides more high-level constructs. The symbols package is also used internally, and may be subject to more frequent breaking changes.

The C symbol set is divided in different sub-packages to allow plugin developers to import only the ones they need. Importing one of the sub-packages automatically includes its prebuilt symbols in the plugin. If one of the prebuilt symbols is imported it would not be possible to re-define it in the plugin, as this would lead to a linking failure due to multiple definitions of the same symbol.

Each sub-package has been designed to only implement one or few symbols. Plugin developers can either decide to implement all the symbols of the sub-packages, or to import only a subset of them and decide to implement some of the symbols manually.

The mapping between the prebuilt C exported symbols and their sub-package has been designed by grouping them depending on their use cases. The mapping is designed as follows:

• info: get_type, get_id, get_description, get_contact, get_version, get_required_api_version, get_event_source, get_extract_event_sources
• fields: plugin_get_fields
• lasterr: plugin_get_last_error
• initialize: plugin_init, plugin_destroy
• open: plugin_open, plugin_close
• nextbatch: plugin_next_batch
• extract: plugin_extract_fields
• evtstr: plugin_event_to_string
• progress: plugin_get_progress

There are no horizontal dependencies between the sub-packages, which means that they are independent from one another. Each sub-package only depends on the definitions of the base-level sdk package, and occasionally uses constructs from the ptr and cgo packages. This makes each sub-package composable, and developers can easily mix manually implemented C symbols with the prebuilt ones, as long as the interface requirements are respected.