From 2be07e4762c0edea518ffa7df1dc973d8b1d1b0e Mon Sep 17 00:00:00 2001
From: Erik Serating <eserating@ravemobilesafety.com>
Date: Mon, 20 Jun 2022 09:50:40 -0400
Subject: [PATCH] Issue #642 - Expose config and INFO response for
 slave_priority

---
 internal/server/config.go | 32 ++++++++++++++++++++++++++------
 internal/server/stats.go  |  3 +++
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/internal/server/config.go b/internal/server/config.go
index b7355900..e17aa438 100644
--- a/internal/server/config.go
+++ b/internal/server/config.go
@@ -25,6 +25,7 @@ const (
 	FollowPort    = "follow_port"
 	FollowID      = "follow_id"
 	FollowPos     = "follow_pos"
+	SlavePriority = "slave_priority"
 	ServerID      = "server_id"
 	ReadOnly      = "read_only"
 	RequirePass   = "requirepass"
@@ -44,12 +45,13 @@ type Config struct {
 
 	mu sync.RWMutex
 
-	_followHost string
-	_followPort int64
-	_followID   string
-	_followPos  int64
-	_serverID   string
-	_readOnly   bool
+	_followHost    string
+	_followPort    int64
+	_followID      string
+	_followPos     int64
+	_slavePriority int64
+	_serverID      string
+	_readOnly      bool
 
 	_requirePassP   string
 	_requirePass    string
@@ -99,6 +101,15 @@ func loadConfig(path string) (*Config, error) {
 		config._serverID = randomKey(16)
 	}
 
+	// Need to be sure we look for existence vs not zero because zero is an intentional setting
+	// anything less than zero will be considered default and will result in no slave_priority
+	// being output when INFO is called.
+	if gjson.Get(json, SlavePriority).Exists() {
+		config._slavePriority = gjson.Get(json, SlavePriority).Int()
+	} else {
+		config._slavePriority = -1
+	}
+
 	// load properties
 	if err := config.setProperty(RequirePass, config._requirePassP, true); err != nil {
 		return nil, err
@@ -167,6 +178,9 @@ func (config *Config) write(writeProperties bool) {
 	if config._followPos != 0 {
 		m[FollowPos] = config._followPos
 	}
+	if config._slavePriority >= 0 {
+		m[SlavePriority] = config._slavePriority
+	}
 	if config._serverID != "" {
 		m[ServerID] = config._serverID
 	}
@@ -426,6 +440,12 @@ func (config *Config) followPort() int {
 	config.mu.RUnlock()
 	return int(v)
 }
+func (config *Config) slavePriority() int {
+	config.mu.RLock()
+	v := config._slavePriority
+	config.mu.RUnlock()
+	return int(v)
+}
 func (config *Config) serverID() string {
 	config.mu.RLock()
 	v := config._serverID
diff --git a/internal/server/stats.go b/internal/server/stats.go
index 503beafe..975665c2 100644
--- a/internal/server/stats.go
+++ b/internal/server/stats.go
@@ -408,6 +408,9 @@ func (s *Server) writeInfoReplication(w *bytes.Buffer) {
 		fmt.Fprintf(w, "role:slave\r\n")
 		fmt.Fprintf(w, "master_host:%s\r\n", s.config.followHost())
 		fmt.Fprintf(w, "master_port:%v\r\n", s.config.followPort())
+		if s.config.slavePriority() >= 0 {
+			fmt.Fprintf(w, "slave_priority:%v\r\n", s.config.slavePriority())
+		}
 	} else {
 		fmt.Fprintf(w, "role:master\r\n")
 		var i int