Migrate to containerd v1.7.0 and update dependencies

* Updates containerd to v1.7.0 and new binary for 32-bit
Arm OSes.
* Updates Go dependencies - openfaas and external

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/google.golang.org/grpc/metadata/metadata.go

@@ -41,16 +41,17 @@ type MD map[string][]string
 // New creates an MD from a given key-value map.
 //
 // Only the following ASCII characters are allowed in keys:
-//  - digits: 0-9
-//  - uppercase letters: A-Z (normalized to lower)
-//  - lowercase letters: a-z
-//  - special characters: -_.
+//   - digits: 0-9
+//   - uppercase letters: A-Z (normalized to lower)
+//   - lowercase letters: a-z
+//   - special characters: -_.
+//
 // Uppercase letters are automatically converted to lowercase.
 //
 // Keys beginning with "grpc-" are reserved for grpc-internal use only and may
 // result in errors if set in metadata.
 func New(m map[string]string) MD {
-	md := MD{}
+	md := make(MD, len(m))
 	for k, val := range m {
 		key := strings.ToLower(k)
 		md[key] = append(md[key], val)
@@ -62,10 +63,11 @@ func New(m map[string]string) MD {
 // Pairs panics if len(kv) is odd.
 //
 // Only the following ASCII characters are allowed in keys:
-//  - digits: 0-9
-//  - uppercase letters: A-Z (normalized to lower)
-//  - lowercase letters: a-z
-//  - special characters: -_.
+//   - digits: 0-9
+//   - uppercase letters: A-Z (normalized to lower)
+//   - lowercase letters: a-z
+//   - special characters: -_.
+//
 // Uppercase letters are automatically converted to lowercase.
 //
 // Keys beginning with "grpc-" are reserved for grpc-internal use only and may
@@ -74,7 +76,7 @@ func Pairs(kv ...string) MD {
 	if len(kv)%2 == 1 {
 		panic(fmt.Sprintf("metadata: Pairs got the odd number of input pairs for metadata: %d", len(kv)))
 	}
-	md := MD{}
+	md := make(MD, len(kv)/2)
 	for i := 0; i < len(kv); i += 2 {
 		key := strings.ToLower(kv[i])
 		md[key] = append(md[key], kv[i+1])
@@ -182,17 +184,51 @@ func FromIncomingContext(ctx context.Context) (MD, bool) {
 	if !ok {
 		return nil, false
 	}
-	out := MD{}
+	out := make(MD, len(md))
 	for k, v := range md {
 		// We need to manually convert all keys to lower case, because MD is a
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		out[key] = copyOf(v)
 	}
 	return out, true
 }
 
+// ValueFromIncomingContext returns the metadata value corresponding to the metadata
+// key from the incoming metadata if it exists. Key must be lower-case.
+//
+// # Experimental
+//
+// Notice: This API is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func ValueFromIncomingContext(ctx context.Context, key string) []string {
+	md, ok := ctx.Value(mdIncomingKey{}).(MD)
+	if !ok {
+		return nil
+	}
+
+	if v, ok := md[key]; ok {
+		return copyOf(v)
+	}
+	for k, v := range md {
+		// We need to manually convert all keys to lower case, because MD is a
+		// map, and there's no guarantee that the MD attached to the context is
+		// created using our helper functions.
+		if strings.ToLower(k) == key {
+			return copyOf(v)
+		}
+	}
+	return nil
+}
+
+// the returned slice must not be modified in place
+func copyOf(v []string) []string {
+	vals := make([]string, len(v))
+	copy(vals, v)
+	return vals
+}
+
 // FromOutgoingContextRaw returns the un-merged, intermediary contents of rawMD.
 //
 // Remember to perform strings.ToLower on the keys, for both the returned MD (MD
@@ -220,13 +256,18 @@ func FromOutgoingContext(ctx context.Context) (MD, bool) {
 		return nil, false
 	}
 
-	out := MD{}
+	mdSize := len(raw.md)
+	for i := range raw.added {
+		mdSize += len(raw.added[i]) / 2
+	}
+
+	out := make(MD, mdSize)
 	for k, v := range raw.md {
 		// We need to manually convert all keys to lower case, because MD is a
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		out[key] = copyOf(v)
 	}
 	for _, added := range raw.added {
 		if len(added)%2 == 1 {