Provider returns secrets for a function

This commit allows the provider to return a list of the names of the
secrets mapped into an openfaas function. This was tested by building
and deploying faasd on multipass and curling the provider directly and
seeing the returned secrets list!

Signed-off-by: Alistair Hey <alistair@heyal.co.uk>

pkg/provider/handlers/functions_test.go

@@ -2,6 +2,8 @@ package handlers
 
 import (
 	"fmt"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"reflect"
 	"testing"
 )
 
@@ -27,3 +29,27 @@ func Test_BuildLabelsAndAnnotationsFromServiceSpec_Annotations(t *testing.T) {
 		t.Errorf("want: '%s' entry in annotation map got: key not found", "current-time")
 	}
 }
+
+func Test_SplitMountToSecrets(t *testing.T) {
+	type test struct {
+		Name     string
+		Input    []specs.Mount
+		Expected []string
+	}
+	tests := []test{
+		{Name: "No matching openfaas secrets", Input: []specs.Mount{{Destination: "/foo/"}}, Expected: []string{}},
+		{Name: "No Mounts", Input: []specs.Mount{{Destination: "/foo/"}}, Expected: []string{}},
+		{Name: "One Mounts IS secret", Input: []specs.Mount{{Destination: "/var/openfaas/secrets/secret1"}}, Expected: []string{"secret1"}},
+		{Name: "Multiple Mounts 1 secret", Input: []specs.Mount{{Destination: "/var/openfaas/secrets/secret1"}, {Destination: "/some/other/path"}}, Expected: []string{"secret1"}},
+		{Name: "Multiple Mounts all secrets", Input: []specs.Mount{{Destination: "/var/openfaas/secrets/secret1"}, {Destination: "/var/openfaas/secrets/secret2"}}, Expected: []string{"secret1", "secret2"}},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.Name, func(t *testing.T) {
+			got := readSecretsFromMounts(tc.Input)
+			if !reflect.DeepEqual(got, tc.Expected) {
+				t.Fatalf("expected %s, got %s", tc.Expected, got)
+			}
+		})
+	}
+}