Code refactoring: Include AgentIdentity

[sarroutbi]

Add agent_registration.rs to include all code
relevant to this kind of operation

Signed-off-by: Sergio Arroutbi [email protected]

[codecov]

Codecov Report

Attention: Patch coverage is 82.89474% with 13 lines in your changes missing coverage. Please review.

Project coverage is 62.96%. Comparing base (a18dbe2) to head (c3285ed).

Files with missing lines	Patch %	Lines
keylime-agent/src/agent_registration.rs	90.00%	7 Missing ⚠️
keylime-agent/src/main.rs	0.00%	6 Missing ⚠️

Additional details and impacted files

Flag	Coverage Δ
e2e-testsuite	62.96% <82.89%> (+0.66%)	⬆️
upstream-unit-tests	62.96% <82.89%> (+0.66%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
keylime-agent/src/main.rs	19.58% <0.00%> (+1.68%)	⬆️
keylime-agent/src/agent_registration.rs	90.00% <90.00%> (ø)

... and 5 files with indirect coverage changes

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[ansasaki]

I think this structure could be called AgentIdentity or similar as it is combining all the info that identifies the agent (UUID, keys, certificates, etc.)

Also it raises to me a question: is it possible that this structure containing the agent identity could be useful out of the context of the agent?

To me it seems it could be useful, for example, if we decide to implement other components in Rust in future which could benefit for having the agent identity structure available as a library.

For this reason I believe this structure could be moved to the keylime library, out of the keylime-agent application.

Also, I believe that we should modify the current implementation of the RegistrarClient in the keylime lib to not include the Agent information, but only the data related with "making requests to the registrar" (e.g. ip, port, etc.).

Then, you could move the code from there that is related to building the structure that contains the agent info to your AgentIdentity structure. Probably using an AgentIdentityBuilder to set the options.

The register_agent method in RegistrarClient could receive an instance of your AgentIdentity and make the registration.

[sarroutbi]

Hello Anderson. Regarding names (AgentActivation->AgentIdentity), I am OK with this.

However, I am still not confident about moving the whole thing to the library, so, if possible, I would like to leave that for another PR.

[sarroutbi]

Another issue I find to extract the code of this PR to the library is the usage of certain code which are parts of the agent itself, such as the Error and the Config

[ansasaki]

Another thing that I would like to ask is to be more descriptive and specific in the PR title, so that when we are going through the PRs, we can get an idea on the changes it is making. "Code refactoring" is not a good title. "Introduce AgentIdentity structure" or "Move agent registration to dedicated module" would be better.