feat(log): use short image/container IDs in logs (#888)

pkg/container/util_test.go

@@ -0,0 +1,46 @@
+package container_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	. "github.com/containrrr/watchtower/pkg/container"
+)
+
+var _ = Describe("container utils", func() {
+	Describe("ShortID", func() {
+		When("given a normal image ID", func() {
+			When("it contains a sha256 prefix", func() {
+				It("should return that ID in short version", func() {
+					actual := ShortID("sha256:0123456789abcd00000000001111111111222222222233333333334444444444")
+					Expect(actual).To(Equal("0123456789ab"))
+				})
+			})
+			When("it doesn't contain a prefix", func() {
+				It("should return that ID in short version", func() {
+					actual := ShortID("0123456789abcd00000000001111111111222222222233333333334444444444")
+					Expect(actual).To(Equal("0123456789ab"))
+				})
+			})
+		})
+		When("given a short image ID", func() {
+			When("it contains no prefix", func() {
+				It("should return the same string", func() {
+					Expect(ShortID("0123456789ab")).To(Equal("0123456789ab"))
+				})
+			})
+			When("it contains a the sha256 prefix", func() {
+				It("should return the ID without the prefix", func() {
+					Expect(ShortID("sha256:0123456789ab")).To(Equal("0123456789ab"))
+				})
+			})
+		})
+		When("given an ID with an unknown prefix", func() {
+			It("should return a short version of that ID including the prefix", func() {
+				Expect(ShortID("md5:0123456789ab")).To(Equal("md5:0123456789ab"))
+				Expect(ShortID("md5:0123456789abcdefg")).To(Equal("md5:0123456789ab"))
+				Expect(ShortID("md5:01")).To(Equal("md5:01"))
+			})
+		})
+	})
+})