From 1b60e8fdb658d4f4b1493eb19520816465a4b1d7 Mon Sep 17 00:00:00 2001
From: Martin Atkins <mart@degeneration.co.uk>
Date: Tue, 17 Oct 2017 18:03:16 -0700
Subject: [PATCH] svchost/auth: HostCredentialsFromMap function

This function deals with turning a map derived from some user input
(e.g. in a config file) into a HostCredentials object, if possible. This
will be used as a standard way to specify credentials so we have a place
to add new credentials types in future and have support for those across
all of our map-based CredentialsSources.
---
 svchost/auth/from_map.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 svchost/auth/from_map.go

diff --git a/svchost/auth/from_map.go b/svchost/auth/from_map.go
new file mode 100644
index 000000000..f91006aec
--- /dev/null
+++ b/svchost/auth/from_map.go
@@ -0,0 +1,18 @@
+package auth
+
+// HostCredentialsFromMap converts a map of key-value pairs from a credentials
+// definition provided by the user (e.g. in a config file, or via a credentials
+// helper) into a HostCredentials object if possible, or returns nil if
+// no credentials could be extracted from the map.
+//
+// This function ignores map keys it is unfamiliar with, to allow for future
+// expansion of the credentials map format for new credential types.
+func HostCredentialsFromMap(m map[string]interface{}) HostCredentials {
+	if m == nil {
+		return nil
+	}
+	if token, ok := m["token"].(string); ok {
+		return HostCredentialsToken(token)
+	}
+	return nil
+}