From f26a98895a4bf503471ce5de07ea662ef0caaf05 Mon Sep 17 00:00:00 2001
From: Sarah Jamie Lewis <sarah@openprivacy.ca>
Date: Tue, 14 Jul 2020 16:35:21 -0700
Subject: [PATCH] Add Metrics (Fix: #21)

---
 networks/tor/BaseOnionService.go | 20 ++++++++++++++++++++
 service.go                       |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/networks/tor/BaseOnionService.go b/networks/tor/BaseOnionService.go
index fe9c2e5..feaf56a 100644
--- a/networks/tor/BaseOnionService.go
+++ b/networks/tor/BaseOnionService.go
@@ -23,6 +23,26 @@ type BaseOnionService struct {
 	lock        sync.Mutex
 }
 
+// Metrics provides a report of useful information about the status of the service e.g. the number of active
+// connections
+func (s *BaseOnionService) Metrics() tapir.ServiceMetrics {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	count := 0
+	s.connections.Range(func(key, value interface{}) bool {
+		connection := value.(tapir.Connection)
+		if !connection.IsClosed() {
+			count++
+		}
+		return true
+	})
+
+	return tapir.ServiceMetrics{
+		ConnectionCount: count,
+	}
+}
+
 // Init initializes a BaseOnionService with a given private key and identity
 // The private key is needed to initialize the Onion listen socket, ideally we could just pass an Identity in here.
 func (s *BaseOnionService) Init(acn connectivity.ACN, sk ed25519.PrivateKey, id *primitives.Identity) {
diff --git a/service.go b/service.go
index 4534644..0c1a9fd 100644
--- a/service.go
+++ b/service.go
@@ -12,12 +12,18 @@ import (
 	"sync"
 )
 
+// ServiceMetrics outlines higher level information about the service e.g. counts of connections
+type ServiceMetrics struct {
+	ConnectionCount int
+}
+
 // Service defines the interface for a Tapir Service
 type Service interface {
 	Init(acn connectivity.ACN, privateKey ed25519.PrivateKey, identity *primitives.Identity)
 	Connect(hostname string, application Application) (bool, error)
 	Listen(application Application) error
 	GetConnection(connectionID string) (Connection, error)
+	Metrics() ServiceMetrics
 	Broadcast(message []byte, capability Capability) error
 	WaitForCapabilityOrClose(connectionID string, capability Capability) (Connection, error)
 	Shutdown()