Please what is the right way to deliver a test (ex: directory, similar test) ?

This is fun!

Thanks for the contribution, it looks quite good, to just read/write bytes objects.

@Lisa999 how does this compare to your implementation?

I see that the ESP IDF has functions to get/set a range of signed/unsigned integer types (8-64 bit). I don't know, is it worth exposing all of that functionality?

@dpgeorge: This is a nice try, but i have to disagree with this approach.
For example:
nvs_set_blob(nvs_handle, key, value, strlen(value));
It's assuming that value is a STRING, but it's using a blob function to store the string.

Here are my functions:
checkNVS()
mod_esp_nvs_set_int (mp_obj_t _key, mp_obj_t _value)
--> only using the i32 function...
mod_esp_nvs_get_int (mp_obj_t _key)
mod_esp_nvs_set_str (mp_obj_t _key, mp_obj_t _value)
--> Using: nvs_set_str(mpy_nvs_handle, key, value)
mod_esp_nvs_get_str (mp_obj_t _key)
mod_esp_nvs_erase (mp_obj_t _key)
mod_esp_nvs_erase_all (void)

example (code to see which reset has been performed for the next cycle):
esp.nvs_setstr('reset', 'rebootasync')

The only thing i'm doubting about is whether to put it into ESP or into ESP32...

I happy to make a PR, IF you promise to pull #3576 after @andynd has fixed it.

This follow Micropython's Django Principle.

Django? Django is all-inclusive, Flask Lightweight.
I would say that Micropython is more like Flask, everything should be lightweight and modular to avoid using huge amounts of memory.

Even so, blob's should be used to store binary data. If you want to store strings, then use the nvs_set_str function. https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/storage/nvs_flash.html

esp_err_tnvs_set_blob(nvs_handlehandle, const char *key, const void *value, size_t length)
set variable length binary value for given key

Thanks @Lisa999 for the input. It's probably a good idea to at least add "type" annotations to the method names so others can be added in the future if needed; such as nvs_set_blob(), nvs_set_i32(), etc.

Looking more at what the ESP IDF provides, I'd also suggest to make the NVS interface an object, rather than just functions in a module. This is because it's possible to open multiple NVS handles. It's like a mini database. Eg:

nvs = esp32.NVS("my_storage", "w") # open read/write
nvs.set_i32("key", 1234)
nvs2 = esp32.NVS("other_storage", "r") # open read-only
blob = nvs2.get_blob("key2")

See #4436 for a related issue.

ESP-IDF Non-volatile storage library docs can be found here:

https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/storage/nvs_flash.html

(Link above is broken though the text is correct)

Thanks @Lisa999 for the input. It's probably a good idea to at least add "type" annotations to the method names so others can be added in the future if needed; such as nvs_set_blob(), nvs_set_i32(), etc.

Looking more at what the ESP IDF provides, I'd also suggest to make the NVS interface an object, rather than just functions in a module. This is because it's possible to open multiple NVS handles. It's like a mini database. Eg:

nvs = esp32.NVS("my_storage", "w") # open read/write
nvs.set_i32("key", 1234)
nvs2 = esp32.NVS("other_storage", "r") # open read-only
blob = nvs2.get_blob("key2")

@dpgeorge: Since you build the Partition class for the ESP32, i'll keep my part of the bargain and have NVS working for Micropython v1.11 . However it's still functions based, do you have an example of a good object based class so i can rewrite my code?

do you have an example of a good object based class so i can rewrite my code?

I think the esp32.Partition() class is a really good example to base NVS on, see #4910.

Also, it might be neater to use subscription to read/write NVS values, similar to how machine.mem32[..] works. Eg:

nvs = esp32.NVS('storage', 'w')
nvs.i32['key'] = 1234 # store value
print(nvs.blob['key2']) # retrieve value

See extmod/machine_mem.c for code to implement that kind of API.

Its not clear to me why Partition class needed to be merged before implementing NVS. There is very little interaction between OTA/Partition functions and nvs functions.

@Lisa999 what was your intention in waiting for Partition functionality to be merged? Also are you working on this PR now ?

@nevercast : the Partition PR is not connected to this PR. I already have a working NVS class, however not object oriented but function oriented. @dpgeorge refered to the Partition class as an example how to build something like an object oriented class. The NVS OO class is on my to do list, probably going to start with the next few weeks.

@Lisa999 Any plans to finish OO implementation of NVS?

@Lisa999 Any plans to finish OO implementation of NVS?

Absolutely, as promised. Is on my todo list. However it gets overridden all the time by urgent matters that take up all of my time. I hope to make a start the next few weeks, i need to get this off my todo list. :-)

@Lisa999 would you mind publishing your work on NVS somewhere? probably I can step in to finish the OO work, as I'm interested in NVS too ...

I do the merge on the commit 60f5b94, I attached the files merged, but I don't know to do this with github.
nvs.zip

This is superseded by the NVS supporte added in c10d431