#Agile IDM Etity Storage
This module uses a leveldb storage and transactions to handle entities in AGILE Identity Management. This module is required in the agile-idm-web component (to validate client secrets), and it is also used by agile-idm-core, also inside agile-idm-web to store entities.
Leveldb is a lightweight, open source, key value database. One of the main advantages for node.js applications is that a value can constitute and object (i.e. an entity for IDM). However, to remain lightweight, its node implementation implements an in-memory locking system, in which the database connection can be instantiated only once to ensure consistency. So, one of the main responsibilities of this component is to offer a module that ensures that only one database connection is used.
Furthermore, this component ensures that even if requests are executed in parallel, the execution of actions is serialized. This is achieved by using the leveldb-transactions node package.
agile-idm-entity-storage offers a high level, promise-based, API to:
- create, read, update and delete entities
- create, delete groups and read group information.
- add and remove entities to a group (equivalent to group update).
- look up entities for a given set of attribute values. For instance, it is possible to find entities with a particular owner and attribute name equal to "my sensor".
Even though some API calls of agile-idm-entity-storage resemble the agile-idm-core API, they are focused on handling storage issues such as transaction synchronization, while the agile-idm-core API also validates the entities schema, enforces policies, and includes owner information in the entities.
agile-idm-entity-storage component is only used by agile-idm-web and by agile-idm-core. However, in case the reader is interested in usage examples, this component is currently used in agile-idm-core to store entities (see https://github.com/Agile-IoT/agile-idm-core/blob/master/lib/api/api.js). Also, given that functionalities are constantly tested with unit test which verify response or expected status codes, the test folder of the agile-idm-entity-storage constitutes a good starting point to interact with the agile-idm-entity-storage node js module.
#Debug mode
If you define the following variable (to be 1) this module will print debugging information.
export DEBUG_IDM_STORAGE=1
If no variable is set, or if any other value different than 1 is set, this component runs in quiet mode.