[Feature Anywhere] Enable plugins to augment visualizations with additional data and context

[ohltyler]

Currently time series visualizations are limited in just showing raw results generated on-the-fly from configured metrics, and don't provide any additional insights about the data shown on the chart. There are several OpenSearch plugins that are tailored towards providing insights into time series data, including Anomaly Detection and Alerting.

To provide an easy way for users to gain more insights with their existing visualizations, as well as help improve visibility and adoption of these additional plugins, we propose a generic framework to allow plugin resources (e.g., anomaly detectors, alerting monitors) to be associated with visualizations, either via automatic generation based on a visualization itself, or existing plugin resources. Additionally, we can support overlaying these additional results on top of the visualization charts.

At a high level, this can be achieved through the following steps:

1. Construct a framework allowing plugins to register an option on the visualization details panel, to let users maintain relationships between a visualization and their plugin resources
2. Introduce a generic VisLayers interface to support multiple ways of overlaying / augmenting data in a visualization chart
3. Migrate the line visualization's charting library from the in-house vislib library to vega-lite, to more easily process & render overlayed data onto the charts
4. Introduce a new feature-anywhere saved object type to persist relationships between a plugin resource and a visualization
5. Introduce a new vis_layers expression function type that can be used to process plugin data and convert into visualization overlay data
6. Intercept the visualization render flow to collect & process any produced VisLayers to show on the chart canvas

All of these new components (Steps 2,4,5 from above) can be maintained and registered in a standalone vis_augmenter plugin - see #2958 for details.

Plugins can onboard to this framework by performing the following steps:

1. Register their plugin as an option in the visualization details panel
2. Register a vis_layers expression function to process their plugin data and convert into a VisLayer.
3. Develop UI components to maintain the relationships between a visualization and plugin resources. This may include auto-creation of resources based on a visualization's config, or linking existing plugin resources. It will require CRUD operations on augment-vis saved objects for persisting these relationships.

Anomaly Detection and Alerting are the first 2 plugins that will be onboarding. Details can be found in their respective meta issues:

• Anomaly Detection: [FEATURE] Support managing and creating anomaly detectors from viz in Dashboard anomaly-detection-dashboards-plugin#400
• Alerting: META - Augmenting Visualizations with Alerts alerting-dashboards-plugin#457

All related issues should be labeled with feature-anywhere

Progress tracker (core Dashboards)

• [Feature Anywhere] Add a generic interface for overlaying data on a Visualization #2882 (PR)
• Support vega-lite v5 #2717 (PR)
• [Feature Anywhere] Add a augment-vis saved object type #2893 (PR)
• [Feature Anywhere] Add a vis_layers expression function type #2894 (PR)
• [Feature Anywhere] Introduce a new Feature-Anywhere plugin #2958 (PR)
• Finalize VisLayer data models #3373 (PR)
• Minimal migration of Visualization line charts to vega-lite #2915 (PR)
• [Feature Anywhere] Collect VisLayers when rendering visualization line charts #3122 (PR)
• [Feature Anywhere] Dynamically update vega spec to show VisLayers #3130 (PR)
• [Feature Anywhere] Support clicking & custom tooltip functionality from vega charts #3317 (PR)
• [Feature Anywhere] Finalize eligibility based on vis configuration #3268 (PR)
• [Feature Anywhere] Support fine-grained error states from VisLayers #3267 (PR)
• [Feature Anywhere] General error handling of VisLayer errors #3580 (PR)
• [Feature Anywhere] Support a 'View Events' flyout for event details #3155 (PR)
• [Feature Anywhere] Advanced settings to soft limit on number of anywhere saved objects on a single visualization #3361 (PR)
• [BUG] Vislib to Vega-lite migrator, fix chart overflow issue #3485
• [BUG] Unrecognized scheme name: elastic when rendering vega charts #3582
• [Feature Anywhere] Framework for plugin registration #2916
• [Feature Anywhere] [Meta] Add documentation for Feature Anywhere #3383
• [Feature Anywhere] Performance test the new feature anywhere integration across OSD and plugins. #3833
• [Feature Anywhere] Add server-side API to track feature usage #3836 (PR)
• [Feature Anywhere] Cleanup of dangling augment-vis saved objs #4044 (PR)
• Add VisLayer error toasts when rendering vis #3649

Current bug tracker (meta issue):

• [Feature Anywhere] Meta Issue tracker #3969

Progress tracker (functional tests)
See https://github.com/opensearch-project/opensearch-dashboards-functional-test/issues?q=is%3Aissue+is%3Aopen+%5BFeature+Anywhere%5D

Future enhancement tracker (not part of initial release):

• [Feature Anywhere] [Enhancement] Support more custom plugin functionality in View Events flyout #3481
• [Feature Anywhere] [Enhancement] Support plugin-granular settings #3509
• [Feature Anywhere] [Enhancement] Add a plugin-consumable table to list associated visualizations #3407
• [Feature Anywhere] [Enhancement] Implement custom find()/findAll() for saved object loader #3566
• Limitation on creating multiple AugmentedVisualizations with the same visID and pluginResourceID #3644
• [Feature Anywhere] VisAugmenter dependencies aren't set sometimes #4138
• [Feature Anywhere] Support more plugin control in VisLayer flyouts #4180

Below are some of the high-level designs describing this feature:
Fig 1: The visualization render workflow design (changes highlighted in red)

Fig 2: The user workflow design (changes highlighted in red):

Below are some of the proposed mockups, using the anomaly detection plugin as an example:

Fig 3: View overlayed data on a visualization chart

Fig 4: View registered plugins in the visualization options panel

Fig 5: View details for the Anomaly Detection plugin

Fig 6: View details for a particular associated anomaly detector

[lezzago]

Alerting Meta task issue: opensearch-project/alerting-dashboards-plugin#457

[amitgalitz]

Anomaly Detection meta task issue: opensearch-project/anomaly-detection-dashboards-plugin#400

[ohltyler]

Added both of those in description ^

[kavilla]

As called out: #3981

We will target this for v2.next for prioritization on Node upgrade.