Default "nvs" partition is first erased to allow for clean example run, followed by writing 2 sets of key value pairs of different types to NVS storage. After that, iteration is performed over the individual data types, as well as the generic NVS_TYPE_ANY, and relevant entry info gained from iteration is verbosely logged.

Iterator creation in this example is performed by nvs_entry_find() and accessing entry info by nvs_entry_info().

Detailed functional description of NVS and API is provided in documentation.

How to use example

Hardware required

This example does not require any special hardware, and can be run on any common development board.

Build and flash

Build the project and flash it to the board, then run monitor tool to view serial output:

idf.py -p PORT flash monitor

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

...
I (265) nvs_iteration_example: Erasing the contents of the default NVS partition...
I (595) nvs_iteration_example: Opening Non-Volatile Storage (NVS) handle for namespace '_mock_data'...
I (605) nvs_iteration_example: Writing u32 mock data key-value pairs to NVS namespace '_mock_data'...
I (605) nvs_iteration_example: Wrote 7 u32 mock data key-value pairs to NVS namespace '_mock_data'.
I (615) nvs_iteration_example: Writing i8 mock data key-value pairs to NVS namespace '_mock_data'...
I (625) nvs_iteration_example: Wrote 7 i8 mock data key-value pairs to NVS namespace '_mock_data'.
I (625) nvs_iteration_example: Committing data in NVS namespace '_mock_data'...
I (635) nvs_iteration_example: NVS handle for namespace '_mock_data' closed.
I (645) nvs_iteration_example: Iterating over NVS_TYPE_U32 data in namespace '_mock_data'...
I (655) nvs_iteration_example: Entry info: key 'system_startup' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (665) nvs_iteration_example: Entry info: key 'user_login' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (675) nvs_iteration_example: Entry info: key 'data_backup' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (685) nvs_iteration_example: Entry info: key 'sched_update' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (695) nvs_iteration_example: Entry info: key 'db_cleanup' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (705) nvs_iteration_example: Entry info: key 'security_scan' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (715) nvs_iteration_example: Entry info: key 'system_shutdown' for data type type NVS_TYPE_U32 in namespace '_mock_data'
I (725) nvs_iteration_example: Iterated over 7 entries.
I (725) nvs_iteration_example: Iterating over NVS_TYPE_I8 data in namespace '_mock_data'...
I (735) nvs_iteration_example: Entry info: key 'temperature' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (745) nvs_iteration_example: Entry info: key 'humidity' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (755) nvs_iteration_example: Entry info: key 'light_level' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (765) nvs_iteration_example: Entry info: key 'motion_detected' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (775) nvs_iteration_example: Entry info: key 'battery_level' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (785) nvs_iteration_example: Entry info: key 'signal_strength' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (795) nvs_iteration_example: Entry info: key 'error_code' for data type type NVS_TYPE_I8 in namespace '_mock_data'
I (805) nvs_iteration_example: Iterated over 7 entries.
I (815) nvs_iteration_example: Iterating over NVS_TYPE_ANY data in namespace '_mock_data'...
I (825) nvs_iteration_example: Iterated over 14 entries.
I (825) nvs_iteration_example: Returning from app_main().
I (835) main_task: Returned from app_main()
...