Adds sherpa.ResolveBool for use in helpers

Provide the method with an env variable name and it will resolve & attempt to validate in a consistent way if the variable is true or false.

The function returns true for 1, t, T, TRUE, true, True. It returns false for all other values (even invalid) and if the variable is not set.

Signed-off-by: Daniel Mikusa <dmikusa@vmware.com>

sherpa/env_var.go

@@ -19,6 +19,7 @@ package sherpa
 import (
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 )
 
@@ -50,3 +51,19 @@ func GetEnvWithDefault(name string, def string) string {
 	}
 	return def
 }
+
+// ResolveBool resolves a boolean value for a configuration option. Returns true for 1, t, T, TRUE, true, True. Returns
+// false for all other values or unset.
+func ResolveBool(name string) bool {
+	s, ok := os.LookupEnv(name)
+	if !ok {
+		return false
+	}
+
+	t, err := strconv.ParseBool(s)
+	if err != nil {
+		return false
+	}
+
+	return t
+}

sherpa/env_var_test.go

@@ -103,4 +103,53 @@ func testEnvVar(t *testing.T, context spec.G, it spec.S) {
 			Expect(sherpa.GetEnvWithDefault("ANOTHER_KEY", "default-value")).To(Equal("default-value"))
 		})
 	})
+
+	context("ResolveBool", func() {
+		context("variable not set", func() {
+			it("returns false if not set", func() {
+				Expect(sherpa.ResolveBool("TEST_KEY")).To(BeFalse())
+			})
+		})
+
+		context("variable is set to true value", func() {
+			it.After(func() {
+				Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+			})
+
+			it("returns true", func() {
+				for _, form := range []string{"1", "t", "T", "TRUE", "true", "True"} {
+					Expect(os.Setenv("TEST_KEY", form))
+					Expect(sherpa.ResolveBool("TEST_KEY")).To(BeTrue())
+					Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+				}
+			})
+		})
+
+		context("variable is set to non-true value", func() {
+			it.After(func() {
+				Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+			})
+
+			it("returns false", func() {
+				for _, form := range []string{"0", "f", "F", "FALSE", "false", "False"} {
+					Expect(os.Setenv("TEST_KEY", form))
+					Expect(sherpa.ResolveBool("TEST_KEY")).To(BeFalse())
+					Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+				}
+			})
+		})
+
+		context("variable is set to an invalid value", func() {
+			it.After(func() {
+				Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+			})
+
+			it("returns false", func() {
+				Expect(os.Setenv("TEST_KEY", "foo"))
+				Expect(sherpa.ResolveBool("TEST_KEY")).To(BeFalse())
+				Expect(os.Unsetenv("TEST_KEY")).To(Succeed())
+			})
+		})
+
+	})
 }