Added Or combinator to TokenSource

README.md

@@ -48,11 +48,15 @@ You will need to ensure that both `githubActor` and `githubTokenSource` are set
 Once this is configured, sbt-github-packages will automatically set your `githubActor` key to its value. That just leaves the `githubTokenSource`. The `TokenSource` ADT has the following possibilities:
 
 ```scala
-sealed trait TokenSource extends Product with Serializable
+sealed trait TokenSource extends Product with Serializable {
+  def ||(that: TokenSource): TokenSource =
+    TokenSource.Or(this, that)
+}
 
 object TokenSource {
   final case class Environment(variable: String) extends TokenSource
   final case class GitConfig(key: String) extends TokenSource
+  final case class Or(primary: TokenSource, secondary: TokenSource) extends TokenSource
 }
 ```
 
@@ -62,6 +66,8 @@ Environment variables are a fairly good default. For example, I have a GitHub to
 githubTokenSource := TokenSource.Environment("GITHUB_TOKEN")
 ```
 
+The `||` combinator allows you to configure multiple token sources which will be tried in order on first-read of the setting.
+
 Note that your CI server will need to set the `GITHUB_TOKEN` environment variable as well, as well as any collaborators on your project. The environment-specific nature of these login credentials are a major part of why they are *not* just strings sitting in the `build.sbt` file. As an example, if you're using Travis, you can do something like the following:
 
 ```bash

src/main/scala/sbtghpackages/GitHubPackagesPlugin.scala

@@ -93,21 +93,26 @@ object GitHubPackagesPlugin extends AutoPlugin {
     userDefaults ++
     authenticationSettings
 
-  def inferredGitHubCredentials(user: String, tokenSource: TokenSource) = {
-    val tokenM = tokenSource match {
+  def inferredGitHubCredentials(user: String, tokenSource: TokenSource): Option[Credentials] = {
+    def make(tokenM: Option[String]) =
+      tokenM map { token =>
+        Credentials(
+          "GitHub Package Registry",
+          "maven.pkg.github.com",
+          user,
+          token)
+      }
+
+    tokenSource match {
+      case TokenSource.Or(primary, secondary) =>
+        inferredGitHubCredentials(user, primary).orElse(
+          inferredGitHubCredentials(user, secondary))
+
       case TokenSource.Environment(variable) =>
-        sys.env.get(variable)
+        make(sys.env.get(variable))
 
       case TokenSource.GitConfig(key) =>
-        Try(s"git config $key".!!).map(_.trim).toOption
-    }
-
-    tokenM map { token =>
-      Credentials(
-        "GitHub Package Registry",
-        "maven.pkg.github.com",
-        user,
-        token)
+        make(Try(s"git config $key".!!).map(_.trim).toOption)
     }
   }
 

src/main/scala/sbtghpackages/TokenSource.scala

@@ -16,9 +16,13 @@
 
 package sbtghpackages
 
-sealed trait TokenSource extends Product with Serializable
+sealed trait TokenSource extends Product with Serializable {
+  def ||(that: TokenSource): TokenSource =
+    TokenSource.Or(this, that)
+}
 
 object TokenSource {
   final case class Environment(variable: String) extends TokenSource
   final case class GitConfig(key: String) extends TokenSource
+  final case class Or(primary: TokenSource, secondary: TokenSource) extends TokenSource
 }