feat: read variables from environment as command (#22)

Author: portellaa

Sources/Command/BasicTypes+ArgumentParser.swift

@@ -0,0 +1,23 @@
+import ArgumentParser
+import Foundation
+import Models
+
+extension Array: ExpressibleByArgument where Element: Decodable {
+  public init?(argument: String) {
+    guard let data = argument.data(using: .utf8) else {
+      return nil
+    }
+
+    guard let decoded = try? JSONDecoder().decode(Self.self, from: data) else {
+      return nil
+    }
+
+    self = decoded
+  }
+}
+
+extension Optional: ExpressibleByArgument where Wrapped: ExpressibleByArgument {
+  public init?(argument: String) {
+    self = Wrapped(argument: argument)
+  }
+}

Sources/Command/Environment.swift

@@ -1,21 +1,49 @@
+import ArgumentParser
 import Foundation
 
 enum Environment {
-  static var decoder: JSONDecoder = JSONDecoder()
+  static var decoder = JSONDecoder()
 
-  static func get<Key: CodingKey>(_ key: Key) -> String? {
-    ProcessInfo.processInfo.environment[key.stringValue]
+  @inlinable
+  static func get(_ key: String) throws -> String {
+    guard let value = ProcessInfo.processInfo.environment[key] else {
+      throw Error.keyNotFound
+    }
+
+    return value
   }
 
-  static func get<Key: CodingKey, D: Decodable>(
-    _ key: Key,
+  static func get<Key: CodingKey>(_ key: Key) throws -> String {
+    try get(key.stringValue)
+  }
+
+  @inlinable
+  static func get<D: Decodable>(
+    _ key: String,
     _ type: D.Type = D.self,
-    decoder: JSONDecoder = Self.decoder
-  ) throws -> D? {
-    guard let data = get(key)?.data(using: .utf8) else {
-      return nil
+    decoder: JSONDecoder? = nil
+  ) throws -> D {
+    guard let data = try get(key).data(using: .utf8) else {
+      throw Error.cannotConvertToData
     }
 
+    let decoder = decoder ?? Self.decoder
+
     return try decoder.decode(D.self, from: data)
   }
+
+  static func get<Key: CodingKey, D: Decodable>(
+    _ key: Key,
+    _ type: D.Type = D.self,
+    decoder: JSONDecoder? = nil
+  ) throws -> D {
+    try get(key.stringValue)
+  }
+}
+
+extension Environment {
+  enum Error: Swift.Error {
+    case keyNotFound
+    case cannotConvertToData
+  }
 }

Sources/Command/run.swift

@@ -1,5 +1,6 @@
 import App
 import ArgumentParser
+import Foundation
 import Models
 import NIO
 import SotoCore
@@ -10,6 +11,16 @@ import SotoEKS
 struct Command: AsyncParsableCommand {
   static var configuration: CommandConfiguration { CommandConfiguration(commandName: "aws-asg-tags") }
 
+  // swiftlint:disable force_try
+
+  @Option(name: .shortAndLong)
+  var clusterName: String = try! Environment.get(ClusterNodesTags.CodingKeys.clusterName)
+
+  @Option(name: .long)
+  var nodePools: [NodePool] = try! Environment.get(ClusterNodesTags.CodingKeys.nodePools)
+
+  @Option(name: .long)
+  var commonTags: [Tag]? = try? Environment.get(ClusterNodesTags.CodingKeys.commonTags)
 
   func run() async throws {
     let logger = Logger(label: "ai.ydata.aws-asg-tags")
@@ -32,31 +43,15 @@ struct Command: AsyncParsableCommand {
 
     let hulk = Hulk(asgClient: asgClient, eksClient: eksClient, logger: logger)
 
-    let clusterNodeTags = try createClusterNodeTags(logger)
-
-    try await hulk.smash(clusterNodeTags)
-  }
-
-  private func createClusterNodeTags(_ logger: Logger) throws -> ClusterNodesTags {
-    guard let clusterName = Environment.get(ClusterNodesTags.CodingKeys.clusterName) else {
-      logger.error("missing value for property \(ClusterNodesTags.CodingKeys.clusterName.description))")
-      throw Error.missingProperty
-    }
-
-    logger.info("extracted clusterName from env: \(clusterName)")
-
-    guard let nodePools: [NodePool] = try Environment.get(ClusterNodesTags.CodingKeys.nodePools) else {
-      logger.error("missing value for property \(ClusterNodesTags.CodingKeys.nodePools.description))")
-      throw Error.missingProperty
-    }
-
-    logger.info("extracted nodePools from env: \(nodePools)")
-
-    let commonTags: [Tag]? = try Environment.get(ClusterNodesTags.CodingKeys.commonTags)
+    let clusterNodeTags = ClusterNodesTags(
+      clusterName: clusterName,
+      commonTags: commonTags,
+      nodePools: nodePools
+    )
 
-    logger.info("commonTags extracted from env: \(commonTags ?? [])")
+    logger.info("processing cluster node tags:\n\(clusterNodeTags)")
 
-    return ClusterNodesTags(clusterName: clusterName, commonTags: commonTags, nodePools: nodePools)
+    try await hulk.smash(clusterNodeTags)
   }
 }