fix build and tests

Author: jason-jackson

Dockerfile

@@ -1,5 +1,6 @@
-FROM golang:1-alpine3.7 as builder
+FROM golang:1-alpine3.22 AS builder
 WORKDIR /go/src/entrypoint
+COPY ./go.mod /go/src/entrypoint
 COPY ./entrypoint.go /go/src/entrypoint/
 RUN go build
 

Dockerfile-tests

@@ -1,4 +1,4 @@
-FROM golang:1-alpine3.7
+FROM golang:1-alpine3.22
 WORKDIR /go/src/entrypoint
 COPY ./go.mod /go/src/entrypoint
 COPY ./entrypoint.go /go/src/entrypoint/

entrypoint.go

@@ -122,6 +122,10 @@ func BuildReplacementsFromEnv() ([]Replacement, error) {
 				return configReplacements, fmt.Errorf("missing required env var: %s. Description: %s", envvar.Name, envvar.Desc)
 			}
 
+			if envvar.Default == "" {
+				continue
+			}
+
 			value = envvar.Default
 		}
 

entrypoint_test.go

@@ -46,9 +46,8 @@ func TestBuildReplacementsFromEnv(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	replacementsCount := len(replacements)
-	if replacementsCount != 6 {
-		t.Fatal("Replacements did not have enough entries, only found", replacementsCount, "but expected 6")
+	if want, got := 7, len(replacements); want != got {
+		t.Fatal("Replacements did not have enough entries: found", got, "but expected", want)
 	}
 }