12,13: The measurements time range and time zone (UTC) are fixed

[nunoguedelha]

The measurements timestamp is fixed to the UTC timezone. The measurements time span is also fixed. We should be able to change both from the web GUI.

[nunoguedelha]

On the installed plugins...

Autoflow View

• This plugin provides the Autoflow View for domain objects in Open MCT. This view allows users to visualize the latest values of a collection of telemetry points in a tabular formatted condensed list. The only option available is to provide the Autoflow View to telemetry.fixed object types only.

Time API and Time Management Plugins

Time Systems (https://github.com/nasa/openmct/blob/master/API.md#defining-and-registering-time-systems)

Time Systems are JavaScript objects that provide some information about the current time reference frame, typically the time display format and the time zone: UTC/GMT, ETC, ...

The example below defines/registers a UTC based time system:

openmct.time.addTimeSystem({
    key: 'utc',
    name: 'UTC Time',
    cssClass = 'icon-clock',
    timeFormat = 'utc',
    durationFormat = 'duration',
    isUTCBased = true
});

Note: 'utc' and 'duration' are formats defined in the utcTimeSystem plugin module.

localTimeSystem

• Installs a local clock source aligned with the UTC time zone.

utcTimeSystem

• Installs a time system that gets the time from a UTC time zone clock server.
• Installs also a local clock aligned with the UTC time zone and which ticks every 100ms.

Time Bounds (https://github.com/nasa/openmct/blob/master/API.md#time-bounds)

The TimeAPI provides a getter/setter for querying and setting time bounds. Time bounds are simply an object with a start and an end end attribute, delimiting the period displayed by time-responsive telemetry views in the active Time System.

const ONE_HOUR = 60 * 60 * 1000;
let now = Date.now();
openmct.time.bounds({start: now - ONE_HOUR, now);

Clocks (https://github.com/nasa/openmct/blob/master/API.md#clocks)

• Clocks can be local (from the host machine), remote (from the network), or tick on anything. For instance, a clock can tick on received Yarp port telemetry samples and return the sample timestamps.

Clocks can tick on anything. For example, a clock could be defined to provide the timestamp of any new data received via a telemetry subscription. This would have the effect of advancing the bounds of views automatically whenever data is received. A clock could also be defined to tick on some remote timing source.

var someClock = {
    key: 'someClock',
    cssClass: 'icon-clock',
    name: 'Some clock',
    description: "Presumably does something useful",
    on: function (event, callback) {
        // Some function that registers listeners, and updates them on a tick
    },
    off: function (event, callback) {
        // Some function that unregisters listeners.
    },
    currentValue: function () {
        // A function that returns the last ticked value for the clock
    }
}

openmct.time.addClock(someClock);

Clock Offsets

Unlike bounds, which represent absolute time values, clock offsets represent relative time spans, start (<0) and end (>0), used to update the start and stop bons on each clock tick.

Current Implementation

The DefaultClock class is implemented in src/utils/clock/DefaultClock.js and extends an EventEmitter. It provides the methods depicted earlier in the someClock example.

The class LocalClock implemented in src/plugins/utcTimeSystem/LocalClock.j extends the DefaultClock class, providing the additional start and stop methods used by the openmct Time API.

The utcTimeSystem installation instantiates a UTCTimeSystem Time System and a LocalClock and registers them: https://github.com/nasa/openmct/blob/ab7e2c57470d3c6076459ad7e3eaa1883cc3b8b0/src/plugins/utcTimeSystem/plugin.js#L34-L40

    return function () {
        return function (openmct) {
            const timeSystem = new UTCTimeSystem();
            openmct.time.addTimeSystem(timeSystem);
            openmct.time.addClock(new LocalClock.default(100));
        };
    };

The clock and Time System are activated in the openmctStaticServer/index.html visualizer client installation file. The clockOffsets are passed in the clock activation: https://github.com/ami-iit/yarp-openmct/blob/0a9bd9b5aeae631227e665ca2d0a0b2d28cbc18d/openmctStaticServer/index.html#L35-L36

• Setting the active time system will trigger a timeSystem event.
• Setting the clock triggers a 'clock' event, followed by a clockOffsets event, and then a bounds event as the offsets are applied to the clock's currentValue().
• Upon being activated, the time API will listen for tick events on the clock by calling clock.on.

Implementation Changes: Time Conductor Configuration (https://github.com/nasa/openmct/blob/master/API.md#the-time-conductor)

The Time Conductor plugin provides a user interface for selecting pre-defined configurations of combined clocks, time systems and time bounds or offsets in Open MCT. The Time Conductor configuration in https://github.com/ami-iit/yarp-openmct/blob/feature/improve-time-range-zone-management/openmctStaticServer/index.html specifies the combinations made available in the GUI. The whole configuration is provided as an array of menu options. Each entry defines...

• the used clock: [string] Active Clock ("Local Clock") or Fixed Time Mode (no active clock, "Fixed Timespan"),

  

• the available timeSystem: [string] the key for the time system that this configuration relates to,

  

• some default bounds (for the "Fixed Timespan" configuration) or clockOffsets (for the "Local Clock" configuration): [object] with start andend` properties,

  

• presets: array of bounds (start|end) or clockOffsets, setting available entries in the history drop down menu,

  

• records: [number] maximum recent bounds to retain in conductor history,

Unused options so far:

• zoomOutLimit: An optional number specifying the longest period of time that can be represented by the conductor when zooming. If a zoomOutLimit is provided, then a zoomInLimit must also be provided. If provided, the zoom slider will automatically become available in the Time Conductor UI.
• zoomInLimit: An optional number specifying the shortest period of time that can be represented by the conductor when zooming. If a zoomInLimit is provided, then a zoomOutLimit must also be provided. If provided, the zoom slider will automatically become available in the Time Conductor UI.

The Time Conductor handles by itself the clock and system activation, so we can discard the lines: https://github.com/ami-iit/yarp-openmct/blob/0a9bd9b5aeae631227e665ca2d0a0b2d28cbc18d/openmctStaticServer/index.html#L35-L36

[nunoguedelha]

I'm still analysing how to integrate the Clock plugin in the Time Conductor. The Clock plugin alone can be added to "My Items" and allows set different time zones.

I will add this improvement eventually, along with the remoteClock in a future PR.