From cb709e8e966d6152edbc6ed46b6dcf5ee7de515b Mon Sep 17 00:00:00 2001
From: ivcosla <ivcoslaj@gmail.com>
Date: Mon, 19 Aug 2019 12:16:21 +0200
Subject: [PATCH] added health endpoint

---
 pkg/hypervisor/hypervisor.go | 29 +++++++++++++++++++++++++++++
 pkg/visor/rpc.go             | 35 +++++++++++++++++++++++++++++++++++
 pkg/visor/rpc_client.go      |  9 +++++++++
 pkg/visor/rpc_test.go        | 21 +++++++++++++++++++++
 4 files changed, 94 insertions(+)

diff --git a/pkg/hypervisor/hypervisor.go b/pkg/hypervisor/hypervisor.go
index d7203b5b69..427a59d3b4 100644
--- a/pkg/hypervisor/hypervisor.go
+++ b/pkg/hypervisor/hypervisor.go
@@ -130,6 +130,7 @@ func (m *Node) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 			r.Get("/user", m.users.UserInfo())
 			r.Post("/change-password", m.users.ChangePassword())
 			r.Get("/nodes", m.getNodes())
+			r.Get("/health", m.getHealth())
 			r.Get("/nodes/{pk}", m.getNode())
 			r.Get("/nodes/{pk}/apps", m.getApps())
 			r.Get("/nodes/{pk}/apps/{app}", m.getApp())
@@ -150,6 +151,34 @@ func (m *Node) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	r.ServeHTTP(w, req)
 }
 
+// VisorHealth represents a node's health report attached to it's pk for identification
+type VisorHealth struct {
+	PK cipher.PubKey `json:"pk"`
+	*visor.HealthInfo
+}
+
+// provides summary of health information for every visor
+func (m *Node) getHealth() http.HandlerFunc {
+	healthStatuses := make([]*VisorHealth, len(m.nodes))
+
+	return func(w http.ResponseWriter, r *http.Request) {
+		m.mu.RLock()
+		for pk, c := range m.nodes {
+			vh := &VisorHealth{PK: pk}
+
+			hi, err := c.Client.Health()
+			if err != nil {
+				httputil.WriteJSON(w, r, http.StatusInternalServerError, err)
+				return
+			}
+
+			vh.HealthInfo = hi
+			healthStatuses = append(healthStatuses, vh)
+		}
+
+	}
+}
+
 type summaryResp struct {
 	TCPAddr string `json:"tcp_addr"`
 	*visor.Summary
diff --git a/pkg/visor/rpc.go b/pkg/visor/rpc.go
index 2f79d9d997..e32990b1ed 100644
--- a/pkg/visor/rpc.go
+++ b/pkg/visor/rpc.go
@@ -5,6 +5,8 @@ import (
 	"errors"
 	"time"
 
+	"net/http"
+
 	"github.com/google/uuid"
 	"github.com/skycoin/dmsg/cipher"
 
@@ -33,6 +35,39 @@ type RPC struct {
 	node *Node
 }
 
+/*
+	<<< NODE HEALTH >>>
+*/
+
+// HealthInfo carries information about visor's external services health represented as http status codes
+type HealthInfo struct {
+	TransportDiscovery int `json:"transport_discovery"`
+	RouteFinder        int `json:"route_finder"`
+	SetupNode          int `json:"setup_node"`
+}
+
+// Health returns health information about the visor
+func (r *RPC) Health(_ *struct{}, out *HealthInfo) error {
+	out.TransportDiscovery = http.StatusOK
+	out.RouteFinder = http.StatusOK
+	out.SetupNode = http.StatusOK
+
+	_, err := r.node.config.TransportDiscovery()
+	if err != nil {
+		out.TransportDiscovery = http.StatusNotFound
+	}
+
+	if r.node.config.Routing.RouteFinder == "" {
+		out.RouteFinder = http.StatusNotFound
+	}
+
+	if len(r.node.config.Routing.SetupNodes) == 0 {
+		out.SetupNode = http.StatusNotFound
+	}
+
+	return nil
+}
+
 /*
 	<<< NODE SUMMARY >>>
 */
diff --git a/pkg/visor/rpc_client.go b/pkg/visor/rpc_client.go
index a0dfcadc56..341feab47f 100644
--- a/pkg/visor/rpc_client.go
+++ b/pkg/visor/rpc_client.go
@@ -20,6 +20,8 @@ import (
 type RPCClient interface {
 	Summary() (*Summary, error)
 
+	Health() (*HealthInfo, error)
+
 	Apps() ([]*AppState, error)
 	StartApp(appName string) error
 	StopApp(appName string) error
@@ -64,6 +66,13 @@ func (rc *rpcClient) Summary() (*Summary, error) {
 	return out, err
 }
 
+// Health calls Health
+func (rc *rpcClient) Health() (*HealthInfo, error) {
+	hi := &HealthInfo{}
+	err := rc.Call("Health", &struct{}{}, hi)
+	return hi, err
+}
+
 // Apps calls Apps.
 func (rc *rpcClient) Apps() ([]*AppState, error) {
 	states := make([]*AppState, 0)
diff --git a/pkg/visor/rpc_test.go b/pkg/visor/rpc_test.go
index 3f151ea60e..9c6bcc5261 100644
--- a/pkg/visor/rpc_test.go
+++ b/pkg/visor/rpc_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"net"
+	"net/http"
 	"net/rpc"
 	"os"
 	"testing"
@@ -19,6 +20,26 @@ import (
 	"github.com/skycoin/skywire/pkg/util/pathutil"
 )
 
+func TestHealth(t *testing.T) {
+	sPK, _ := cipher.GenerateKeyPair()
+
+	c := &Config{}
+	c.Transport.Discovery = "foo"
+	c.Routing.SetupNodes = []cipher.PubKey{sPK}
+	c.Routing.RouteFinder = "foo"
+
+	t.Run("Report all the services as available", func(t *testing.T) {
+		rpc := &RPC{&Node{config: c}}
+		h := &HealthInfo{}
+		err := rpc.Health(&struct{}{}, h)
+		require.NoError(t, err)
+
+		assert.Equal(t, h.TransportDiscovery, http.StatusOK)
+		assert.Equal(t, h.SetupNode, http.StatusOK)
+		assert.Equal(t, h.RouteFinder, http.StatusOK)
+	})
+}
+
 func TestListApps(t *testing.T) {
 	apps := []AppConfig{
 		{App: "foo", AutoStart: false, Port: 10},