Support load snapshot

[zhiyuanliang-ms]

New API:

const config = await load(connectionString, {
    selectors: [
        { snapshotName: "MySnapshot" }, // load keyvalue from snapshot
        { keyFilter: "test*", labelFilter: "test" }
    ],
    featureFlagOptions: {
        enabled: true,
        selectors: [
            { snapshotName: "MySnapshot" }, // load feature flags from snapshot
            { keyFilter: "*", labelFilter: "test" }
        ]
    }
});

Allow to use snapshot selector to load key value or feature flags

Note, for expilicity, if a snapshot contains feature flag, the feature flags will only be loaded when the snapshot is used for featureFlagOptions.selectors

This implementation is the same as kubernetes provider ref and ref

[Copilot]

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

src/AzureAppConfigurationImpl.ts:946

• Ensure that the logic for handling snapshot selectors, including the error conditions, is covered by tests.

if (selector.snapshotName) {

[juniwang]

the impl looks good to me. Should we add or update our test cases to cover snapshot?

[zhiyuanliang-ms]

@juniwang Do you mean add more testcases?

[juniwang]

yes