Add support for filtering by tags

[amerjusupovic]

Extends the existing APIs AzureAppConfigurationOptions.Select and FeatureFlagOptions.Select to have a new parameter that supports passing tags that will be used to filter key-values and feature flags. Key-values and feature flags will only be returned if they contain all of the tags and corresponding values passed to the tagFilters parameter.

Updated APIs

public AzureAppConfigurationOptions Select(
    string keyFilter, 
    string labelFilter = LabelFilter.Null, 
    IEnumerable<string> tagFilters = null)

public FeatureFlagOptions Select(
    string featureFlagFilter, 
    string labelFilter = LabelFilter.Null, 
    IEnumerable<string> tagFilters = null)

Example Usage

config.AddAzureAppConfiguration(options =>
{
    options.Select(KeyFilter.Any, LabelFilter.Null, new List<string> { "group=g1", "tag=value" });
})

config.AddAzureAppConfiguration(options =>
{
    options.UseFeatureFlags(ffOptions =>
    {
        ffOptions.Select(KeyFilter.Any, LabelFilter.Null, new List<string> { "group=g1", "tag=value" });
    });
})

Filtering for tags with empty and null value

You can use the TagValue class to filter for tags that have null value. You can also filter for empty string by constructing a tag filter string like "EmptyTag=".

Key-value as a json:

{
	"key": "TestKey",
	"label": null,
	"value": "TestValue",
	"content_type": "",
	"tags": {
		"EmptyTag": "",
		"NullTag": null
	}
}

To select key-value:

options.Select(KeyFilter.Any, LabelFilter.Null, new List<string> { "EmptyTag=", $"NullTag={TagValue.Null}" });

[avanigupta]

Can you also update the PR description with the right parameter name?

[amerjusupovic]

Can you also update the PR description with the right parameter name?

Thanks, updated

The base branch was changed.

[amerjusupovic]

Removed preview changes after changing target branch to main