@pegma/flags-azure-appconfig

Azure App Configuration FlagProvider for Pegma hosts.

[!IMPORTANT] Pegma is in early 0.x development. This package's public API is unstable.

The host constructs and injects an App Configuration reader. This package never imports the Azure SDK, never owns a client singleton, and does not evaluate targeting filters or percentage rollouts. It translates a setting into a FlagResolution.

Microsoft documents two setting shapes this adapter understands:

• ordinary key-values, looked up by the flag key (or a host keyOf)
• feature flags, identified by content type application/vnd.microsoft.appconfig.ff+json;charset=utf-8

Feature-flag keys in App Configuration use the documented prefix .appconfig.featureflag/. Pass keyOf: azureFeatureFlagKey when the host stores flags that way. This package does not invent a second layout.

import { createAzureAppConfigFlagProvider } from "@pegma/flags-azure-appconfig";
import { createFlagsClient, declareFlags, flag } from "@pegma/flags-core";
import type { Logger } from "@pegma/spine";

const schema = declareFlags({
  checkoutEnabled: flag.boolean({ defaultValue: false }),
});

const logger: Logger = {
  log(level, message, fields) {
    console.log(level, message, fields);
  },
};

const provider = createAzureAppConfigFlagProvider({
  reader: {
    async getConfigurationSetting({ key, label }) {
      try {
        return await appConfig.getConfigurationSetting({ key, label });
      } catch (error) {
        if (isNotFound(error)) {
          return undefined;
        }
        throw error;
      }
    },
  },
});

const client = createFlagsClient({ schema, logger, provider });

A missing key is DEFAULT_FALLBACK. A feature flag with enabled: false is DISABLED. An enabled document that still carries targeting filters or a percentage rollout is rejected — this adapter does not evaluate those rules and will not report TARGETING_MATCH for them. Wrap Azure Feature Management in the injected reader and return an already-evaluated setting if the host needs that evaluation.