From e0eb330d42a197917c5642a9b849de07db478cad Mon Sep 17 00:00:00 2001
From: Hidde Beydals <hello@hidde.co>
Date: Tue, 14 Apr 2020 11:07:06 +0200
Subject: [PATCH] Add source interface spec

---
 docs/spec/v1alpha1/common.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/docs/spec/v1alpha1/common.md b/docs/spec/v1alpha1/common.md
index 70f50011..560e8250 100644
--- a/docs/spec/v1alpha1/common.md
+++ b/docs/spec/v1alpha1/common.md
@@ -4,6 +4,21 @@ Common defines resources used across all source types.
 
 ## Specification
 
+### Source interface
+
+Source objects should adhere to the `Source` interface. This interface exposes the [interval](#source-synchronization)
+and [artifact](#source-status) of the source to clients without the prerequisite of knowing the source kind:
+
+````go
+type Source interface {
+	// GetInterval returns the interval at which the source is updated.
+	GetInterval() metav1.Duration
+
+	// GetArtifact returns the latest artifact from the source, or nil.
+	GetArtifact() *Artifact
+}
+````
+
 ### Source synchronization
 
 Source objects should contain a `spec.interval` field that tells the controller at which interval to check for updates: