[MDS] UI polishment for MDS support of Timeline visualization

[zhongnansu]

Tasks

• Polish error message to be data_source_name is not supported. Contact your administrator to start using multiple data sources when data source feature is not enabled
  
  Link PR:

2. Place data source name before the index name in the expression. Hierarchically user selects data source first, then index name, then metric and timestamp

• Add data source helper text into the help tooltip
  

[zhongnansu]

• For task 1: Update error message in timeline visualization when MDS disabled #7069
• For task 2: "place data source name before the index name". Based on @huyaboo, is not doable. Could you add more context?
• For task 3, I found that there's already helper text added in the helper tool tip. See below screenshot
  

cc: @xeniatup @BionIT

[xeniatup]

For task 2: "place data source name before the index name". Based on @huyaboo, is not doable. Could you add more context?
I would not consider it a blocker. The suggestion was based on the general hierarchy of the objects (data source contains multiple indexes, an index has metric, etc..)

[huyaboo]

For task 2: "place data source name before the index name". Based on @huyaboo, is not doable. Could you add more context?

If a specific Timeline visualization does not specify field names for its arguments, the arguments are assigned to the fields in a specific order: queries, metric, split, index, ... (see snippet below for order)

In other words, if data_source_name were placed first or in the middle, it would break existing Timeline visualizations because the argument order would be modified. This is why data_source_name is placed last.

OpenSearch-Dashboards/src/plugins/vis_type_timeline/server/series_functions/opensearch/index.js

Lines 40 to 124 in 7aa61e4

	args: [
	{
	name: 'q',
	types: ['string', 'null'],
	multi: true,
	help: i18n.translate('timeline.help.functions.opensearch.args.qHelpText', {
	defaultMessage: 'Query in lucene query string syntax',
	}),
	},
	{
	name: 'metric',
	types: ['string', 'null'],
	multi: true,
	help: i18n.translate('timeline.help.functions.opensearch.args.metricHelpText', {
	defaultMessage:
	'An opensearch metric agg: avg, sum, min, max, percentiles or cardinality, followed by a field. ' +
	'E.g., "sum:bytes", "percentiles:bytes:95,99,99.9" or just "count"',
	description:
	`avg, sum, min, max, percentiles and cardinality are keywords in the expression ` +
	`and must not be translated. Also don't translate the examples.`,
	}),
	},
	{
	name: 'split',
	types: ['string', 'null'],
	multi: true,
	help: i18n.translate('timeline.help.functions.opensearch.args.splitHelpText', {
	defaultMessage:
	'An opensearch field to split the series on and a limit. E.g., "{hostnameSplitArg}" to get the top 10 hostnames',
	values: {
	hostnameSplitArg: 'hostname:10',
	},
	}),
	},
	{
	name: 'index',
	types: ['string', 'null'],
	help: i18n.translate('timeline.help.functions.opensearch.args.indexHelpText', {
	defaultMessage:
	'Index to query, wildcards accepted. Provide Index Pattern name for scripted fields and ' +
	'field name type ahead suggestions for metrics, split, and timefield arguments.',
	description:
	'"metrics", "split" and "timefield" are referring to parameter names and should not be translated.',
	}),
	},
	{
	name: 'timefield',
	types: ['string', 'null'],
	help: i18n.translate('timeline.help.functions.opensearch.args.timefieldHelpText', {
	defaultMessage: 'Field of type "date" to use for x-axis',
	description: '"date" is a field type and should not be translated.',
	}),
	},
	{
	name: 'kibana',
	types: ['boolean', 'null'],
	help: i18n.translate('timeline.help.functions.opensearch.args.opensearchDashboardsHelpText', {
	defaultMessage:
	'Respect filters on OpenSearch Dashboards dashboards. Only has an effect when using on OpenSearch Dashboards dashboards',
	}),
	},
	{
	name: 'opensearchDashboards',
	types: ['boolean', 'null'],
	help: i18n.translate('timeline.help.functions.opensearch.args.opensearchDashboardsHelpText', {
	defaultMessage:
	'Respect filters on OpenSearch Dashboards dashboards. Only has an effect when using on OpenSearch Dashboards dashboards',
	}),
	},
	{
	name: 'interval', // You really shouldn't use this, use the interval picker instead
	types: ['string', 'null'],
	help: i18n.translate('timeline.help.functions.opensearch.args.intervalHelpText', {
	defaultMessage: `**DO NOT USE THIS**. It's fun for debugging fit functions, but you really should use the interval picker`,
	}),
	},
	{
	name: 'data_source_name',
	types: ['string', 'null'], // If null, the query will proceed with local cluster
	help: i18n.translate('timeline.help.functions.opensearch.args.dataSourceNameHelpText', {
	defaultMessage:
	'Specify a data source to query from. This will only work if multiple data sources is enabled',
	}),
	},
	],