Manage Azure App Configuration Settings

This skill centralizes application configuration using the Azure App Configuration SDK for Java (com.azure:azure-data-appconfiguration, version 1.8.0, installable directly or via the Azure SDK BOM). A ConfigurationClient (or async ConfigurationAsyncClient) is built from a connection string or, preferably, Entra ID credentials (DefaultAzureCredentialBuilder) against an endpoint. Five key concepts anchor the model: a Configuration Setting (a key-value pair with an optional label), a Label (a dimension for separating settings, typically by environment), a Feature Flag (a special setting for feature management), a Secret Reference (a setting that points to a Key Vault secret rather than storing a value directly), and a Snapshot (an immutable, point-in-time view of a set of settings). Core CRUD covers addConfigurationSetting (create-only, fails if it exists), setConfigurationSetting (create-or-overwrite), getConfigurationSetting, and deleteConfigurationSetting, each with conditional variants using ETags (getConfigurationSettingWithResponse with ifChanged returning HTTP 304 if unmodified, and ifUnchanged guards on set/delete for optimistic concurrency, preventing lost updates from concurrent modifications). Listing and filtering use a SettingSelector to match by key pattern (wildcards like app/*), by label, by multiple comma-separated key filters, or to list historical revisions of a single key. Feature flags are modeled with FeatureFlagConfigurationSetting, supporting rollout filters like Microsoft.Percentage for percentage-based gradual rollouts, and can be enabled/disabled and re-saved. Secret references (SecretReferenceConfigurationSetting) store a Key Vault secret URI rather than the secret value itself. Settings can be locked with setReadOnly to protect critical production values from accidental changes, and cleared back to writable when needed. Snapshots are created as a long-running operation (beginCreateSnapshot with a name and a list of ConfigurationSettingsFilters, polled to completion), then can be fetched, have their settings listed, archived, recovered, or enumerated by name pattern via SnapshotSelector. An async client mirrors this API with reactive-stream (subscribe) semantics for high-throughput scenarios, and errors surface as HttpResponseException (e.g. HTTP 404 for a missing setting).

Use this skill when centralizing configuration across environments (Dev/Staging/Production via labels), managing feature flags for gradual rollouts or A/B testing, referencing Key Vault secrets without duplicating them, or creating immutable configuration snapshots for releases. It is not a secrets-storage service itself - actual secret values still live in Key Vault, with App Configuration only holding the reference - and read-only protection is meant for critical settings, not a substitute for proper access control on the store.

Input is configuration keys, values, and labels, feature flag definitions with rollout filters, or Key Vault secret URIs. Output is stored/retrieved ConfigurationSetting objects (including specialized FeatureFlagConfigurationSetting and SecretReferenceConfigurationSetting subtypes), paged listings filtered by key/label, revision history, and named immutable snapshots.

Built on the Azure App Configuration Java SDK (ConfigurationClient/ConfigurationAsyncClient), authenticated via a connection string or Azure Identity's DefaultAzureCredentialBuilder, with Secret References pointing to Azure Key Vault.

<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-data-appconfiguration</artifactId>
    <version>1.8.0</version>
</dependency>

Java developers centralizing application configuration across environments, managing feature-flag rollouts, referencing Key Vault secrets, or needing immutable configuration snapshots for releases and audits.