Playback modes: live mode, configured sim runs, pre-computed trajectories

[interim17]

Use Case

Viewer branch #442 (prefetching) was merged but is being reverted as it introduced some bugs. I am expanding this issue description to include discussion of those issues, as I think this issue of defining playback modes is a prerequisite to solving some of those issues.

IClientSimulatorImpl defines these playback modes:

export declare const enum ClientPlayBackType {
    ID_LIVE_SIMULATION = 0,
    ID_PRE_RUN_SIMULATION = 1,
    ID_TRAJECTORY_FILE_PLAYBACK = 2,
    LENGTH = 3
}

In order to use BioSimulators (and other) APIs, and to manage playback, caching, and interaction with live/running client simulators we need to meaningfully distinguish between these playback modes in both local and remote contexts.

Clarify naming of interfaces:

• Is "pre-run-simulation" a playback mode? #463
• Are ISimulator and IClientSimulatorImpl well named? #462

Define playback modes:

• live, pre-run and pre-computed modes should be defined at some level (controller?)
• different modes should allow/expose/trigger different playback and streaming behaviors and controls
• define/enforce approach to interacting with live/client sims (sendUpdate, local methods, frameRequests, etc.)
• configure RemoteSimulator, particularly sendUpdate, for running remote procedural sims
• define/configure caching options and behavior for live/procedural sims
• procedural sims to adapt to any necessary changes as viewer defines playback modes

General caching updates/maintenance:

• ensure sequential order of cached frames
• cache logging, some required for front end features and some required for dev purposes
• manage cache trimming to prevent loss of current rendered frame
• handle requesting frames previous to cache, and fragmented cache, without clearing cache
• should cached frames from procedural simulations be allowed to be discontinuous?
• ensure that file changing results in rejection of inflight frames
• return a promise when sending websocket requests to allow async chaining of sequential requests
• initialize simulations with frame 0

Prefetching:

• ability to control streaming behavior distinct from playback behavior, and distinguish streaming head distinct from playback head
• ability to ensure sync and communication of back end and front end streaming head
• checks to ensure cache (or cache fragments) only contain continuous frames
• build behavior behind the scenes without unnecessary exposure of public methods

Future steps:

• defining approach to pre-run sims
• manage caching if pre-run exceeds cache limits
• build JSON writer to export live and preconfigured sim runs, capture color changes, manage discontinuities of frame that result from cache trimming
• expand to JSON writer to binary writer?
• current BioSimulators API integration is a pre-run that utilizes auto-conversion, expand to live mode?
• expand user configuration of display features (geometries, etc.) on pre-run sims
• update test bed with necessary features to manage playback modes and take to UX to explore website/other front end implementations

Acceptance Criteria

TBD
Please describe how you know this is done

Details

Please provide any helpful specifications

TBD