Enhancement: Session Error handling and caching

[nodiesBlade]

Github issue

N/A

Description

Occasionally during session rollover, dispatcher nodes will be syncing up to the latest session. During this time, gateway server would request for a specific sesssion, however the dispatcher (due to Pocket core code) will return the old session. This is an issue because Gateway server caches sessions, under the assumption that when requesting a specific session, then the dispatcher will return the proper session.

Example:

1. Blockchain progresses to block 14001
2. Dispatcher reports latest height as 14001
3. Gateway operator sends a request for new sessions for block 14001
4. Dispatcher returns sessions from 13997
5. Gateway operator caches incorrect sessions.

In order to fix this, we add a explicit error check that compares the requested session with the returned session. If there is a mismatch, we return an error in our basic_client implementation.

Other misc changes:

• Add manual cache cleaner for sessions and node cache
• Proper fallback to env variable for altruist
• Expose P90 Latency to qos nodes

Type of change

Please delete option that is not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Related PRs

List related PRs below

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other_pr	link