Add support for Azure App Configuration

RELEASE_NOTES.md

@@ -1,6 +1,9 @@
 Release Notes
 =============
 
+## 1.9.28
+* App Configuration: Add support for Azure App Configuration stores, key-value items, and feature flags.
+
 ## 1.9.27
 * Storage Accounts: Add `AccountKey` member to return just the storage account key and `ConnectionString` member to return the connection string. The existing `Key` member is now obsolete (it incorrectly returned a connection string instead of just the key).
 * Network Manager: Add support for Azure Network Manager with security admin configurations, rule collections, rules with IP ranges and service tags, and network groups.

docs/content/api-overview/resources/app-configuration.md

@@ -0,0 +1,111 @@
+---
+title: "App Configuration"
+date: 2026-04-17T00:00:00+00:00
+chapter: false
+weight: 1
+---
+
+#### Overview
+The App Configuration builder creates Azure App Configuration stores, which are a central repository for managing application settings and feature flags.
+
+* Configuration Store (`Microsoft.AppConfiguration/configurationStores`)
+* Key Values (`Microsoft.AppConfiguration/configurationStores/keyValues`)
+
+#### Builder Keywords
+
+##### configurationStore
+
+| Keyword | Purpose |
+|-|-|
+| name | Sets the name of the App Configuration store. |
+| sku | Sets the SKU of the store. Defaults to `Free`. Options: `Free`, `Developer`, `Standard`, `Premium`. |
+| disable_local_auth | Disables local (access-key) authentication, requiring Azure AD / RBAC only. |
+| enable_purge_protection | Enables purge protection (Standard SKU only). Once enabled, it cannot be disabled. |
+| public_network_access | Sets public network access: `Enabled` or `Disabled`. |
+| soft_delete_retention_in_days | Sets the soft-delete retention period in days (Standard SKU only, 1-7 days). |
+| data_plane_authentication_mode | Sets the data plane authentication mode: `Local` or `Passthrough`. |
+| add_feature_flag | Adds a single feature flag to the store. |
+| add_feature_flags | Adds a list of feature flags to the store. |
+| add_key_value | Adds a single key-value item to the store. |
+| add_key_values | Adds a list of key-value items to the store. |
+| add_tag | Adds an ARM tag to the store. |
+| add_tags | Adds multiple ARM tags to the store. |
+| depends_on | Adds a dependency to the store. |
+
+#### Key Value Fields
+
+| Field | Purpose |
+|-|-|
+| Key | The key name for the item. |
+| Label | An optional label to distinguish between different environments or configurations. |
+| Value | The value to store. |
+| ContentType | Optional MIME content type (e.g. `application/json` for JSON values). |
+| KeyValueTags | Optional App Configuration item tags (not ARM resource tags). |
+
+#### Feature Flag Fields
+
+| Field | Purpose |
+|-|-|
+| Name | The name of the feature flag. |
+| Description | A human-readable description of the flag. |
+| Label | An optional label (can be empty string for no label). |
+| State | `true` if the flag is enabled, `false` if disabled. |
+
+#### Configuration Members
+
+| Member | Purpose |
+|-|-|
+| ResourceId | The ARM resource ID of the App Configuration store. |
+| Endpoint | Returns an ARM expression for the data plane endpoint URL of the store. |
+
+#### Example
+
+```fsharp
+open Farmer
+open Farmer.Builders
+open Farmer.ConfigurationStore
+
+let myConfig = configurationStore {
+    name "my-app-config"
+    sku Standard
+    disable_local_auth
+    add_tags [ "env", "prod"; "team", "platform" ]
+
+    add_feature_flags [
+        {
+            Name = "DarkMode"
+            Description = "Enable dark mode UI"
+            Label = ""
+            State = true
+        }
+        {
+            Name = "BetaFeature"
+            Description = "Beta feature available to select users"
+            Label = "beta"
+            State = false
+        }
+    ]
+
+    add_key_values [
+        {
+            Key = "Api:BaseUrl"
+            Label = Some "prod"
+            Value = "https://api.example.com"
+            ContentType = None
+            KeyValueTags = Map.empty
+        }
+        {
+            Key = "FeatureSettings"
+            Label = None
+            Value = """{"timeout":30,"retries":3}"""
+            ContentType = Some "application/json"
+            KeyValueTags = Map [ "environment", "production" ]
+        }
+    ]
+}
+
+let deployment = arm {
+    location Location.NorthEurope
+    add_resource myConfig
+}
+```

src/Farmer/Arm/ConfigurationStore.fs

@@ -0,0 +1,116 @@
+[<AutoOpen>]
+module Farmer.Arm.ConfigurationStore
+
+open Farmer
+open Farmer.ConfigurationStore
+
+let configurationStores =
+    ResourceType("Microsoft.AppConfiguration/configurationStores", "2024-05-01")
+
+let keyValues =
+    ResourceType("Microsoft.AppConfiguration/configurationStores/keyValues", "2024-05-01")
+
+type ConfigFeatureFlag = {
+    Name: string
+    Description: string
+    Label: string
+    State: bool
+    ConfigurationStoreId: ResourceId
+} with
+
+    member this.ResourceName =
+        let labelSuffix = if this.Label = "" then "" else $"${this.Label}"
+        ResourceName $"{this.ConfigurationStoreId.Name.Value}/.appconfig.featureflag~2F{this.Name}{labelSuffix}"
+
+    interface IArmResource with
+        member this.ResourceId = keyValues.resourceId this.ResourceName
+
+        member this.JsonModel =
+            let enabled = this.State |> string |> _.ToLower()
+
+            let featureFlagValue =
+                $"""{{"id":"{this.Name}","description":"{this.Description}","enabled":{enabled}}}"""
+
+            {|
+                keyValues.Create(this.ResourceName, dependsOn = [ this.ConfigurationStoreId ]) with
+                    properties = {|
+                        value = featureFlagValue
+                        contentType = "application/vnd.microsoft.appconfig.ff+json;charset=utf-8"
+                    |}
+            |}
+
+type KeyValue = {
+    /// The name of the key value in the format `{storeName}/{key}` or `{storeName}/{key}$label`.
+    Name: ResourceName
+    Value: string
+    ContentType: string option
+    /// Tags applied to the App Configuration key-value item (not ARM resource tags).
+    KeyValueTags: Map<string, string>
+    Dependencies: ResourceId Set
+} with
+
+    interface IArmResource with
+        member this.ResourceId = keyValues.resourceId this.Name
+
+        member this.JsonModel = {|
+            keyValues.Create(this.Name, dependsOn = this.Dependencies) with
+                properties = {|
+                    value = this.Value
+                    contentType = this.ContentType |> Option.toObj
+                    tags =
+                        if this.KeyValueTags.IsEmpty then
+                            null
+                        else
+                            box this.KeyValueTags
+                |}
+        |}
+
+type ConfigurationStore = {
+    Name: ResourceName
+    Location: Location
+    Sku: Sku
+    DisableLocalAuth: bool option
+    EnablePurgeProtection: bool option
+    PublicNetworkAccess: Farmer.FeatureFlag option
+    SoftDeleteRetentionInDays: int option
+    DataPlaneAuthenticationMode: DataPlaneAuthenticationMode option
+    Tags: Map<string, string>
+    Dependencies: ResourceId Set
+} with
+
+    interface IArmResource with
+        member this.ResourceId = configurationStores.resourceId this.Name
+
+        member this.JsonModel = {|
+            configurationStores.Create(this.Name, this.Location, this.Dependencies, this.Tags) with
+                sku = {|
+                    name =
+                        match this.Sku with
+                        | Free -> "free"
+                        | Developer -> "developer"
+                        | Standard -> "standard"
+                        | Premium -> "premium"
+                |}
+                properties = {|
+                    disableLocalAuth = this.DisableLocalAuth |> Option.toNullable
+                    enablePurgeProtection = this.EnablePurgeProtection |> Option.toNullable
+                    publicNetworkAccess =
+                        this.PublicNetworkAccess
+                        |> Option.map (fun f ->
+                            match f with
+                            | Enabled -> "Enabled"
+                            | Disabled -> "Disabled")
+                        |> Option.toObj
+                    softDeleteRetentionInDays = this.SoftDeleteRetentionInDays |> Option.toNullable
+                    dataPlaneProxy =
+                        this.DataPlaneAuthenticationMode
+                        |> Option.map (fun mode ->
+                            box {|
+                                authenticationMode =
+                                    match mode with
+                                    | Local -> "Local"
+                                    | Passthrough -> "Pass-through"
+                            |})
+                        |> Option.toObj
+                |}
+        |}