azure-appconfiguration-ts

Author's original introduction

Build applications using Azure App Configuration SDK for JavaScript (@azure/app-configuration). Use when working with configuration settings, feature flags, Key Vault references, dynamic refresh, or centralized configuration management.

SkillPi interpretation

Tasks

azure-appconfiguration-ts

Audience

Use the scope in the original author introduction.

Inputs and outputs

See the complete source; users must confirm cloud data transfers.

Software, accounts and paid services

This azure-appconfiguration-ts package contains Microsoft Azure SDK documentation and examples, not a runtime-verified installer. Check SDK names/versions, tenant/subscription and actual endpoints; grant only task-specific least privilege. Never put administrator credentials or real secrets in samples, logs or commits. Connected cloud services may receive selected text, documents, audio, messages, logs or other input and incur charges; confirm scope, redaction and costs first. Ask the user to confirm each resource creation/update/deletion, key/access change or outbound message and test with disposable resources before production. Replace and verify placeholder endpoints and samples. SkillPi checked pinned source, complete attachments and static/antivirus evidence only; it did not run the SDK, verify service compatibility or authorize cloud access.

Limits and differences

Original author introduction preserved; Chinese is a corresponding translation. Examples were not run by SkillPi; versions, compatibility and outcomes are author claims.

Testing

Not tested

Security rating and access scope

caution · Static evidence review; not a runtime safety guarantee.

This azure-appconfiguration-ts package contains Microsoft Azure SDK documentation and examples, not a runtime-verified installer. Check SDK names/versions, tenant/subscription and actual endpoints; grant only task-specific least privilege. Never put administrator credentials or real secrets in samples, logs or commits. Connected cloud services may receive selected text, documents, audio, messages, logs or other input and incur charges; confirm scope, redaction and costs first. Ask the user to confirm each resource creation/update/deletion, key/access change or outbound message and test with disposable resources before production. Replace and verify placeholder endpoints and samples. SkillPi checked pinned source, complete attachments and static/antivirus evidence only; it did not run the SDK, verify service compatibility or authorize cloud access.

Before use, confirm and authorize actual file access, external services and network destinations in your host. This review grants no runtime permissions.

Original SKILL.md

---
name: azure-appconfiguration-ts
description: Build applications using Azure App Configuration SDK for JavaScript (@azure/app-configuration). Use when working with configuration settings, feature flags, Key Vault references, dynamic refresh, or centralized configuration management.
license: MIT
metadata:
  author: Microsoft
  version: "1.0.0"
  package: '@azure/app-configuration'
---

# Azure App Configuration SDK for TypeScript

Centralized configuration management with feature flags and dynamic refresh.

## Installation

```bash
# Low-level CRUD SDK
npm install @azure/app-configuration @azure/identity

# High-level provider (recommended for apps)
npm install @azure/app-configuration-provider @azure/identity

# Feature flag management
npm install @microsoft/feature-management
```

## Environment Variables

```bash
AZURE_APPCONFIG_ENDPOINT=https://<your-resource>.azconfig.io
# OR
AZURE_APPCONFIG_CONNECTION_STRING=Endpoint=https://...;Id=...;Secret=...
AZURE_TOKEN_CREDENTIALS=prod # Required only if DefaultAzureCredential is used in production
```

## Authentication

```typescript
import { AppConfigurationClient } from "@azure/app-configuration";
import { DefaultAzureCredential, ManagedIdentityCredential } from "@azure/identity";

// Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=<specific_credential>
const credential = new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]});
// Or use a specific credential directly in production:
// See https://learn.microsoft.com/javascript/api/overview/azure/identity-readme?view=azure-node-latest#credential-classes
// const credential = new ManagedIdentityCredential();

const client = new AppConfigurationClient(
  process.env.AZURE_APPCONFIG_ENDPOINT!,
  credential
);

// Connection string
const client2 = new AppConfigurationClient(
  process.env.AZURE_APPCONFIG_CONNECTION_STRING!
);
```

## CRUD Operations

### Create/Update Settings

```typescript
// Add new (fails if exists)
await client.addConfigurationSetting({
  key: "app:settings:message",
  value: "Hello World",
  label: "production",
  contentType: "text/plain",
  tags: { environment: "prod" },
});

// Set (create or update)
await client.setConfigurationSetting({
  key: "app:settings:message",
  value: "Updated value",
  label: "production",
});

// Update with optimistic concurrency
const existing = await client.getConfigurationSetting({ key: "myKey" });
existing.value = "new value";
await client.setConfigurationSetting(existing, { onlyIfUnchanged: true });
```

### Read Settings

```typescript
// Get single setting
const setting = await client.getConfigurationSetting({
  key: "app:settings:message",
  label: "production",  // optional
});
console.log(setting.value);

// List with filters
const settings = client.listConfigurationSettings({
  keyFilter: "app:*",
  labelFilter: "production",
});

for await (const setting of settings) {
  console.log(`${setting.key}: ${setting.value}`);
}
```

### Delete Settings

```typescript
await client.deleteConfigurationSetting({
  key: "app:settings:message",
  label: "production",
});
```

### Lock/Unlock (Read-Only)

```typescript
// Lock
await client.setReadOnly({ key: "myKey", label: "prod" }, true);

// Unlock
await client.setReadOnly({ key: "myKey", label: "prod" }, false);
```

## App Configuration Provider

### Load Configuration

```typescript
import { load } from "@azure/app-configuration-provider";
import { DefaultAzureCredential } from "@azure/identity";

const appConfig = await load(
  process.env.AZURE_APPCONFIG_ENDPOINT!,
  new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]}),
  {
    selectors: [
      { keyFilter: "app:*", labelFilter: "production" },
    ],
    trimKeyPrefixes: ["app:"],
  }
);

// Map-style access
const value = appConfig.get("settings:message");

// Object-style access
const config = appConfig.constructConfigurationObject({ separator: ":" });
console.log(config.settings.message);
```

### Dynamic Refresh

```typescript
const appConfig = await load(endpoint, credential, {
  selectors: [{ keyFilter: "app:*" }],
  refreshOptions: {
    enabled: true,
    refreshIntervalInMs: 30_000,  // 30 seconds
  },
});

// Trigger refresh (non-blocking)
appConfig.refresh();

// Listen for refresh events
const disposer = appConfig.onRefresh(() => {
  console.log("Configuration refreshed!");
});

// Express middleware pattern
app.use((req, res, next) => {
  appConfig.refresh();
  next();
});
```

### Key Vault References

```typescript
const appConfig = await load(endpoint, credential, {
  selectors: [{ keyFilter: "app:*" }],
  keyVaultOptions: {
    credential: new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]}),
    secretRefreshIntervalInMs: 7200_000,  // 2 hours
  },
});

// Secrets are automatically resolved
const dbPassword = appConfig.get("database:password");
```

## Feature Flags

### Create Feature Flag (Low-Level)

```typescript
import {
  featureFlagPrefix,
  featureFlagContentType,
  FeatureFlagValue,
  ConfigurationSetting,
} from "@azure/app-configuration";

const flag: ConfigurationSetting<FeatureFlagValue> = {
  key: `${featureFlagPrefix}Beta`,
  contentType: featureFlagContentType,
  value: {
    id: "Beta",
    enabled: true,
    description: "Beta feature",
    conditions: {
      clientFilters: [
        {
          name: "Microsoft.Targeting",
          parameters: {
            Audience: {
              Users: ["user@example.com"],
              Groups: [{ Name: "beta-testers", RolloutPercentage: 50 }],
              DefaultRolloutPercentage: 0,
            },
          },
        },
      ],
    },
  },
};

await client.addConfigurationSetting(flag);
```

### Load and Evaluate Feature Flags

```typescript
import { load } from "@azure/app-configuration-provider";
import {
  ConfigurationMapFeatureFlagProvider,
  FeatureManager,
} from "@microsoft/feature-management";

const appConfig = await load(endpoint, credential, {
  featureFlagOptions: {
    enabled: true,
    selectors: [{ keyFilter: "*" }],
    refresh: {
      enabled: true,
      refreshIntervalInMs: 30_000,
    },
  },
});

const featureProvider = new ConfigurationMapFeatureFlagProvider(appConfig);
const featureManager = new FeatureManager(featureProvider);

// Simple check
const isEnabled = await featureManager.isEnabled("Beta");

// With targeting context
const isEnabledForUser = await featureManager.isEnabled("Beta", {
  userId: "user@example.com",
  groups: ["beta-testers"],
});
```

## Snapshots

```typescript
// Create snapshot
const snapshot = await client.beginCreateSnapshotAndWait({
  name: "release-v1.0",
  retentionPeriod: 2592000,  // 30 days
  filters: [{ keyFilter: "app:*", labelFilter: "production" }],
});

// Get snapshot
const snap = await client.getSnapshot("release-v1.0");

// List settings in snapshot
const settings = client.listConfigurationSettingsForSnapshot("release-v1.0");
for await (const setting of settings) {
  console.log(`${setting.key}: ${setting.value}`);
}

// Archive/recover
await client.archiveSnapshot("release-v1.0");
await client.recoverSnapshot("release-v1.0");

// Load from snapshot (provider)
const config = await load(endpoint, credential, {
  selectors: [{ snapshotName: "release-v1.0" }],
});
```

## Labels

```typescript
// Create settings with labels
await client.setConfigurationSetting({
  key: "database:host",
  value: "dev-db.example.com",
  label: "development",
});

await client.setConfigurationSetting({
  key: "database:host",
  value: "prod-db.example.com",
  label: "production",
});

// Filter by label
const prodSettings = client.listConfigurationSettings({
  keyFilter: "*",
  labelFilter: "production",
});

// No label (null label)
const noLabelSettings = client.listConfigurationSettings({
  labelFilter: "\0",
});

// List available labels
for await (const label of client.listLabels()) {
  console.log(label.name);
}
```

## Key Types

```typescript
import {
  AppConfigurationClient,
  ConfigurationSetting,
  FeatureFlagValue,
  SecretReferenceValue,
  featureFlagPrefix,
  featureFlagContentType,
  secretReferenceContentType,
  ListConfigurationSettingsOptions,
} from "@azure/app-configuration";

import { load } from "@azure/app-configuration-provider";

import {
  FeatureManager,
  ConfigurationMapFeatureFlagProvider,
} from "@microsoft/feature-management";
```

## Best Practices

1. **Use provider for apps** - `@azure/app-configuration-provider` for runtime config
2. **Use low-level for management** - `@azure/app-configuration` for CRUD operations
3. **Enable refresh** - For dynamic configuration updates
4. **Use labels** - Separate configurations by environment
5. **Use snapshots** - For immutable release configurations
6. **Sentinel pattern** - Use a sentinel key to trigger full refresh
7. **RBAC roles** - `App Configuration Data Reader` for read-only access

Copyright and license notice

    MIT License

    Copyright (c) Microsoft Corporation.

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE