From 7000d0e5090f305bbc56bd1397ceb61996107232 Mon Sep 17 00:00:00 2001
From: Ming Xu <mingx@vmware.com>
Date: Wed, 17 Apr 2019 16:28:58 +0800
Subject: [PATCH 1/2] Make sure check won't fail if image tag not exist on
 registry server.

Signed-off-by: Ming Xu <mingx@vmware.com>
---
 cmd/check/main.go | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/cmd/check/main.go b/cmd/check/main.go
index 247dc39..def151f 100644
--- a/cmd/check/main.go
+++ b/cmd/check/main.go
@@ -62,11 +62,15 @@ func main() {
 		return
 	}
 
+	var missingTag bool
 	digest, err := image.Digest()
 	if err != nil {
-		logrus.Errorf("failed get image digest: %s", err)
-		os.Exit(1)
-		return
+		missingTag = checkMissingManifest(err)
+		if !missingTag {
+			logrus.Errorf("failed to get cursor image digest: %s", err)
+			os.Exit(1)
+			return
+		}
 	}
 
 	response := CheckResponse{}
@@ -93,15 +97,7 @@ func main() {
 		var missingDigest bool
 		_, err = digestImage.Digest()
 		if err != nil {
-			if rErr, ok := err.(*remote.Error); ok {
-				for _, e := range rErr.Errors {
-					if e.Code == remote.ManifestUnknownErrorCode {
-						missingDigest = true
-						break
-					}
-				}
-			}
-
+			missingDigest = checkMissingManifest(err)
 			if !missingDigest {
 				logrus.Errorf("failed to get cursor image digest: %s", err)
 				os.Exit(1)
@@ -114,9 +110,24 @@ func main() {
 		}
 	}
 
-	response = append(response, resource.Version{
-		Digest: digest.String(),
-	})
+	if !missingTag {
+		response = append(response, resource.Version{
+			Digest: digest.String(),
+		})
+	}
 
 	json.NewEncoder(os.Stdout).Encode(response)
 }
+
+func checkMissingManifest(err error) bool {
+	var missing bool
+	if rErr, ok := err.(*remote.Error); ok {
+		for _, e := range rErr.Errors {
+			if e.Code == remote.ManifestUnknownErrorCode {
+				missing = true
+				break
+			}
+		}
+	}
+	return missing
+}

From 1b442b2793913c01c5091b664e5219e428e6b0aa Mon Sep 17 00:00:00 2001
From: Ming Xu <mingx@vmware.com>
Date: Fri, 10 May 2019 11:24:03 +0800
Subject: [PATCH 2/2] Add test case for check not exist image.

Signed-off-by: Ming Xu <mingx@vmware.com>
---
 check_test.go | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/check_test.go b/check_test.go
index c7a97f1..9be1ba8 100644
--- a/check_test.go
+++ b/check_test.go
@@ -210,4 +210,36 @@ var _ = Describe("Check", func() {
 			})
 		})
 	})
+
+	Context("when invoked with not exist image", func() {
+		BeforeEach(func() {
+			req.Source = resource.Source{
+				Repository: "concourse/test-image-static",
+				RawTag:     "not-exist-image",
+			}
+			req.Version = nil
+		})
+
+		It("returns empty digest", func() {
+			Expect(res).To(Equal([]resource.Version{}))
+		})
+
+		Context("against a private repo with credentials", func() {
+			BeforeEach(func() {
+				req.Source = resource.Source{
+					Repository: dockerPrivateRepo,
+					RawTag:     "not-exist-image",
+
+					Username: dockerPrivateUsername,
+					Password: dockerPrivatePassword,
+				}
+
+				checkDockerPrivateUserConfigured()
+			})
+
+			It("returns empty digest", func() {
+				Expect(res).To(Equal([]resource.Version{}))
+			})
+		})
+	})
 })