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.go

@@ -3,6 +3,7 @@ package handlers
 import (
 	"context"
 	"fmt"
+	"github.com/opencontainers/runtime-spec/specs-go"
 	"log"
 	"strings"
 
@@ -22,6 +23,7 @@ type Function struct {
 	IP          string
 	labels      map[string]string
 	annotations map[string]string
+	secrets     []string
 }
 
 // ListFunctions returns a map of all functions with running tasks on namespace
@@ -71,12 +73,19 @@ func GetFunction(client *containerd.Client, name string) (Function, error) {
 
 	labels, annotations := buildLabelsAndAnnotations(allLabels)
 
+	spec, err := c.Spec(ctx)
+	if err != nil {
+		return Function{}, fmt.Errorf("unable to load function spec for reading secrets: %s, error %s", name, err)
+	}
+
+	secrets := readSecretsFromMounts(spec.Mounts)
+
 	fn.name = containerName
 	fn.namespace = faasd.FunctionNamespace
 	fn.image = image.Name()
 	fn.labels = labels
 	fn.annotations = annotations
-
+	fn.secrets = secrets
 	replicas := 0
 	task, err := c.Task(ctx, nil)
 	if err == nil {
@@ -105,6 +114,18 @@ func GetFunction(client *containerd.Client, name string) (Function, error) {
 	return fn, nil
 }
 
+func readSecretsFromMounts(mounts []specs.Mount) []string {
+	secrets := []string{}
+	for _, mnt := range mounts {
+		x := strings.Split(mnt.Destination, "/var/openfaas/secrets/")
+		if len(x) > 1 {
+			secrets = append(secrets, x[1])
+		}
+
+	}
+	return secrets
+}
+
 // buildLabelsAndAnnotations returns a separated list with labels first,
 // followed by annotations by checking each key of ctrLabels for a prefix.
 func buildLabelsAndAnnotations(ctrLabels map[string]string) (map[string]string, map[string]string) {