DS-1732 channel definition opts cache

[akuzni2]

Summary

Add ChannelDefinitionOptsCache to optimize access to ReportCodec options especially in outcome and reporting.

Current usage of ChannelDefinition Opts requires parsing Opts from JSON Bytes -> struct which has an impact on performance with many channels.

See the added bechmark test for performance gain of switching to cache approach.

• 40-50x improvement of using the Cache + type assertion over direct JSON parsing.

Cache Design and Usage

The design of the cache needed to work with varying types of Opts as each ReportCodec manages it's own Opts struct. Therefore what the cache stores is a generic type any which is faster to type assert than it is to re-parse from JSON bytes.

Where we need to access Opts - we can expose a new OptsProvider and each codec that we'd like information from can Implement it such as TimeResolutionProvider or ABIProvider or SomeOtherUniqueOptProvider. Not all codecs need implement these interfaces which is good interface segregation.

Interface Change

Noting that interface was changed ReportCodec.Encode()

• Added parsedOpts interface{} parameter
• • Codecs check if non-nil and use cached value, otherwise fall back to parsing cd.Opts

This was chosen as it's easier at the call site when encoding with various possibilities of ReportCodecs to use the pattern of:

• opts := optsCache.Get(channelId)
• report Encode(report, opts)