From 698f420e2798f99f136fc438fb1333c3b8d30c06 Mon Sep 17 00:00:00 2001
From: Maelkum <aleksandar.cekrlic@gmail.com>
Date: Sat, 7 Oct 2023 22:52:33 +0200
Subject: [PATCH] Add support for "one-of" attestors alongside "each"

---
 models/execute/request.go            | 14 --------------
 models/execute/request_attributes.go | 25 ++++++++++++++++++++++++
 node/attributes.go                   | 29 +++++++++++++++++++++++-----
 3 files changed, 49 insertions(+), 19 deletions(-)
 create mode 100644 models/execute/request_attributes.go

diff --git a/models/execute/request.go b/models/execute/request.go
index 402fdafd..877b195c 100644
--- a/models/execute/request.go
+++ b/models/execute/request.go
@@ -1,7 +1,5 @@
 package execute
 
-import "github.com/libp2p/go-libp2p/core/peer"
-
 // Request describes an execution request.
 type Request struct {
 	FunctionID string      `json:"function_id"`
@@ -49,15 +47,3 @@ type ResultAggregation struct {
 	Type       string      `json:"type,omitempty"`
 	Parameters []Parameter `json:"parameters,omitempty"`
 }
-
-type Attributes struct {
-	// Values specify which attributes the node in question should have.
-	// At the moment we support strict equality only, so no `if RAM >= 16GB` types of conditions.
-	Values []Parameter `json:"values,omitempty"`
-
-	// Should we accept nodes whose attributes are not attested?
-	AttestationRequired bool `json:"attestation_required,omitempty"`
-
-	// Explicitly request specific attestors.
-	Attestors []peer.ID `json:"attestors,omitempty"`
-}
diff --git a/models/execute/request_attributes.go b/models/execute/request_attributes.go
new file mode 100644
index 00000000..8e1737fe
--- /dev/null
+++ b/models/execute/request_attributes.go
@@ -0,0 +1,25 @@
+package execute
+
+import (
+	"github.com/libp2p/go-libp2p/core/peer"
+)
+
+type Attributes struct {
+	// Values specify which attributes the node in question should have.
+	// At the moment we support strict equality only, so no `if RAM >= 16GB` types of conditions.
+	Values []Parameter `json:"values,omitempty"`
+
+	// Should we accept nodes whose attributes are not attested?
+	AttestationRequired bool `json:"attestation_required,omitempty"`
+
+	// Explicitly request specific attestors.
+	Attestors AttributeAttestors `json:"attestors,omitempty"`
+}
+
+type AttributeAttestors struct {
+	// Each of the listed attestors should be found.
+	Each []peer.ID `json:"each,omitempty"`
+
+	// Any one of these attestors should be found.
+	OneOf []peer.ID `json:"one_of,omitempty"`
+}
diff --git a/node/attributes.go b/node/attributes.go
index 46292bbb..5c0143e9 100644
--- a/node/attributes.go
+++ b/node/attributes.go
@@ -11,6 +11,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/peer"
 
 	"github.com/blocklessnetwork/b7s-attributes/attributes"
+	"github.com/blocklessnetwork/b7s/models/blockless"
 	"github.com/blocklessnetwork/b7s/models/execute"
 )
 
@@ -62,15 +63,18 @@ func haveAttributes(have attributes.Attestation, want execute.Attributes) error
 		return errors.New("attestors required but none found")
 	}
 
-	// If the client wants specific attestors, check if they're present.
-	if len(want.Attestors) > 0 {
-
-		attestors := make(map[peer.ID]struct{}, len(have.Attestors))
+	// If we need to check attestors, create a map of them now.
+	var attestors map[peer.ID]struct{}
+	if len(want.Attestors.Each) > 0 || len(want.Attestors.OneOf) > 0 {
+		attestors = make(map[peer.ID]struct{}, len(have.Attestors))
 		for _, attestor := range have.Attestors {
 			attestors[attestor.Signer] = struct{}{}
 		}
+	}
 
-		for _, wa := range want.Attestors {
+	// If the client wants specific attestors, check if they're present.
+	if len(want.Attestors.Each) > 0 {
+		for _, wa := range want.Attestors.Each {
 			_, ok := attestors[wa]
 			if !ok {
 				return fmt.Errorf("attestor %s explicitly requested but not found", wa.String())
@@ -78,6 +82,21 @@ func haveAttributes(have attributes.Attestation, want execute.Attributes) error
 		}
 	}
 
+	// If the client wants some of these attestors, check if at least one if found.
+	if len(want.Attestors.OneOf) > 0 {
+		var found bool
+		for _, wa := range want.Attestors.OneOf {
+			_, ok := attestors[wa]
+			if ok {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return fmt.Errorf("at least one attestor wanted but none found (wanted: %s)", blockless.PeerIDsToStr(want.Attestors.OneOf))
+		}
+	}
+
 	// It doesn't make a lot of sense to require attestors without wanting specific attributes,
 	// but if that's the case, and there's no attributes wanted, we're done now.
 	if len(want.Values) == 0 {