tart ip: keep waiting for the /var/db/dhcpd_leases file to appear (#254)

cirruslabs · Sep 22, 2022 · afbc2e0 · afbc2e0
1 parent 0229138
commit afbc2e0
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Showing 2 changed files with 13 additions and 6 deletions.
diff --git a/Sources/tart/Commands/IP.swift b/Sources/tart/Commands/IP.swift
@@ -44,10 +44,10 @@ struct IP: AsyncParsableCommand {
     let waitUntil = Calendar.current.date(byAdding: .second, value: Int(secondsToWait), to: Date.now)!
 
     repeat {
-      if let ip = try Leases().resolveMACAddress(macAddress: vmMACAddress) {
+      if let leases = try Leases(), let ip = try leases.resolveMACAddress(macAddress: vmMACAddress) {
         return ip
       }
-      
+
       // wait a second
       try await Task.sleep(nanoseconds: 1_000_000_000)
     } while Date.now < waitUntil

diff --git a/Sources/tart/MACAddressResolver/Leases.swift b/Sources/tart/MACAddressResolver/Leases.swift
@@ -19,14 +19,21 @@ enum LeasesError: Error {
 class Leases {
   private let leases: [MACAddress : Lease]
 
-  convenience init() throws {
+  convenience init?() throws {
     try self.init(URL(fileURLWithPath: "/var/db/dhcpd_leases"))
   }
 
-  convenience init(_ fromURL: URL) throws {
-    let fileContents = try String(contentsOf: fromURL, encoding: .utf8)
+  convenience init?(_ fromURL: URL) throws {
+    do {
+      let urlContents = try String(contentsOf: fromURL, encoding: .utf8)
+      try self.init(urlContents)
+    } catch {
+      if error.isFileNotFound() {
+        return nil
+      }
 
-    try self.init(fileContents)
+      throw error
+    }
   }
 
   init(_ fromString: String) throws {