Mixed mode implementation breaks the code of the IOTAs using iotagent-node-lib

[fgalan]

After merging the "mixed mode" NGSI-LD related PR #947, the code of the IOTAs using iotagent-node-lib got broken.

It seems that PR removes a function checkNgsi2() that IOTAs code needs.

An "emergency fix" was done to recover the CI e2e in PRs #957 and #959 (and also a little comment addition in #962). However, a proper fix needs to be done (with the current solution I'm not sure if the mixed mode will work at all).

We need the contributors of NGSI-LD functionality to take care of this and provide a proper fix, please.

(This issue is created in the iotagent-node-lib repository as "common place" for IOTAs, although probably IOTAs code also need to be modified)

CC: @jason-fox

[jason-fox]

According to the checkNgsi2() method documentation:

It checks if the configuration file states the use of NGSIv2. Returns the supported NGSI format

What precisely does this mean? Prior to NGSI-LD checkNgsi2() returned a boolean true if the operation defined in config.js was not NGSI-v1. This was used for legacy checks within the iota-agent-node-lib codebase and frequently resulted in if ... then .. else clauses before I refactored the NGSI-v1, NGSI-v2 and NGSI-LD subclasses.

With NGSI-LD added to the codebase does checkNgsi2() mean:

• I am configured in pure NGSI-v2 mode? i.e. true for NGSI-v2 only
• I am capable of parsing NGSI-v2 requests? i.e. true for NGSI-v2 or mixed
• I am not running in NGSI-v1 legacy mode? This is currently described as isCurrentNgsi()

Or is more info required like checkNgsiLD(typeInformation) where mixed mode may give true or false dependent upon the configuration of the device.

Alternatively should the return value no longer be a boolean and now be a string value like ngsiVersion()?

[fgalan]

checkNgsi2() was based on the static setting in config.js and probably it doesn't have sense after the changes done in PR #947.

This issue is not about recovering checkNgsi2() as it was. It is about to align IOT Agents implementation with the library API changes done in PR #947, as that PR breaks the library-usercode API. If at the end checkNgsi2() is not needed because the IOT Agents are now using the new functions (ngsiVersion(), isCurrentNgsi(), etc.), that's also fine and checkNgsi2() can be removed at the end.

[jason-fox]

So this is a request to update which repos exactly? Where is checkNgsi2() used externally?

[jason-fox]

Ahh got it - like in IoTAgent JSON:

if (attribute === constants.TIMESTAMP_ATTRIBUTE) {
        if (iotAgentLib.configModule.checkNgsi2()) {
            return constants.TIMESTAMP_TYPE_NGSI2;
        }
        return constants.TIMESTAMP_TYPE;
    }

This should be isCurrentNgsi()

[fgalan]

So this is a request to update which repos exactly? Where is checkNgsi2() used externally?

Main IOTAs (and IOTA Manager) should be reviewed for checkNgsi2() usages. I mean:

• https://github.com/telefonicaid/iotagent-json
• https://github.com/telefonicaid/iotagent-ul
• https://github.com/telefonicaid/sigfox-iotagent
• https://github.com/telefonicaid/lightweightm2m-iotagent
• https://github.com/telefonicaid/iotagent-manager

[jason-fox]

Unlike the other agents Sigfox has no timestamp support using checkNgsi2()
IoT Agent Manager has no instances of checkNgsi2()

It looks like all instances in the IoT Agent codebase meant if not NGSIv1 which is now called isCurrentNgsi() to account for NGSI-v2, NGSI-LD and mixed mode.

[fgalan]

The following links can be used to check usage of checkNgsi2 in every repository:

• https://github.com/telefonicaid/iotagent-json/search?q=checkNgsi2
• https://github.com/telefonicaid/iotagent-ul/search?q=checkNgsi2
• https://github.com/telefonicaid/lightweightm2m-iotagent/search?q=checkNgsi2
• https://github.com/telefonicaid/sigfox-iotagent/search?q=checkNgsi2
• https://github.com/telefonicaid/iotagent-manager/search?q=checkNgsi2

After merging the PRs, all them return 0 results, so all the IOTA Lib "users" have been fixed.

With regards to the unmerged PR #965, I think that a better approach would be just to drop the checkNgsi2() function from the iotagent-node-lib API. Given that all the library users have been already adapted this function is no longer needed.

@jason-fox what do you think?

[jason-fox]

Sure, no problem, I can remove it. Although the bigger issue is that what is considered as the full external interface of the library is not correctly documented. There is a growing divergence between what is listed here and technically accessible and what is listed in the docs as accessible functions.

The fact that config is exposed implies that any method in commonConfig.js could be used externally - it would make a lot more sense to restrict this to a smaller set of methods on fiware-iotagent-lib.js only.

[fgalan]

After merging PR #965 I think this issue can be closed.

With regards to your comments on documentation of the external interface, I fully agree. Documentation should be reviewed in order to match exactly that external interface (and, once done, be very careful with new PRs modifying that external interface to ensure the documentation is modified accordingly).