From 42900a5b0f7ddebc101110701604b4c42b4b9aee Mon Sep 17 00:00:00 2001
From: Mikhail Alpinskiy <m.alpinskiy@vk.team>
Date: Mon, 16 Dec 2024 17:41:37 +0300
Subject: [PATCH] Application name

---
 statshouse.go | 58 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 12 deletions(-)

diff --git a/statshouse.go b/statshouse.go
index e438c7f..1a6501a 100644
--- a/statshouse.go
+++ b/statshouse.go
@@ -215,14 +215,24 @@ func StopRegularMeasurement(id int) {
 // Specifying empty StatsHouse address will make the client silently discard all metrics.
 // if you get compiler error after updating to recent version of library, pass statshouse.DefaultNetwork to network parameter
 func NewClient(logf LoggerFunc, network string, statsHouseAddr string, defaultEnv string) *Client {
+	return NewClientEx(ConfigureArgs{
+		Logger:         logf,
+		Network:        network,
+		StatsHouseAddr: statsHouseAddr,
+		DefaultEnv:     defaultEnv,
+	})
+}
+
+func NewClientEx(args ConfigureArgs) *Client {
+	logf := args.Logger
 	if logf == nil {
 		logf = log.Printf
 	}
-	maxSize := maxPayloadSize(network)
+	maxSize := maxPayloadSize(args.Network)
 	c := &Client{
 		logF:    logf,
-		addr:    statsHouseAddr,
-		network: network,
+		addr:    args.StatsHouseAddr,
+		network: args.Network,
 		packet: packet{
 			buf:     make([]byte, batchHeaderLen, maxSize),
 			maxSize: maxSize,
@@ -230,7 +240,8 @@ func NewClient(logf LoggerFunc, network string, statsHouseAddr string, defaultEn
 		close:        make(chan chan struct{}),
 		w:            map[metricKey]*bucket{},
 		wn:           map[metricKeyNamed]*bucket{},
-		env:          defaultEnv,
+		app:          args.AppName,
+		env:          args.DefaultEnv,
 		regularFuncs: map[int]func(*Client){},
 		tsUnixSec:    uint32(time.Now().Unix()),
 	}
@@ -265,6 +276,7 @@ type Client struct {
 
 	// transport
 	transportMu sync.RWMutex
+	app         string
 	env         string // if set, will be put into key0/env
 	network     string
 	addr        string
@@ -293,6 +305,14 @@ type Client struct {
 	bucketCount *atomic.Int32
 }
 
+type ConfigureArgs struct {
+	Logger         LoggerFunc
+	AppName        string // application name
+	DefaultEnv     string // default environment
+	Network        string // default "udp"
+	StatsHouseAddr string // default "127.0.0.1:13337"
+}
+
 type packet struct {
 	buf        []byte
 	maxSize    int
@@ -312,6 +332,7 @@ type tcpConn struct {
 	wouldBlockSize atomic.Int32
 
 	*Client
+	app string
 	env string
 	net.Conn
 
@@ -322,7 +343,7 @@ type tcpConn struct {
 	closeErr chan error
 }
 
-func (c *Client) netDial(env, network, addr string) (netConn, error) {
+func (c *Client) netDial(env, network, addr, app string) (netConn, error) {
 	conn, err := net.Dial(network, addr)
 	if err != nil {
 		c.rareLog("[statshouse] failed to dial statshouse: %v", err)
@@ -339,6 +360,7 @@ func (c *Client) netDial(env, network, addr string) (netConn, error) {
 	}
 	t := &tcpConn{
 		Client:   c,
+		app:      app,
 		env:      env,
 		Conn:     conn,
 		r:        make(chan []byte, tcpConnBucketCount),
@@ -428,8 +450,9 @@ func (t *tcpConn) send() {
 				name: "__src_client_write_err",
 			}
 			fillTag(&k, "0", t.env)
-			fillTag(&k, "1", "1") // lang: golang
-			fillTag(&k, "2", "1") // kind: would block
+			fillTag(&k, "1", "1")   // lang: golang
+			fillTag(&k, "2", "1")   // kind: would block
+			fillTag(&k, "3", t.app) // application name
 			p.sendValues(nil, &k, "", 0, 0, []float64{float64(n)})
 			p.writeBatchHeader()
 			if _, err = t.Conn.Write(p.buf); err != nil {
@@ -519,6 +542,16 @@ func (c *Client) callRegularFuncs(regularCache []func(*Client)) []func(*Client)
 }
 
 func (c *Client) configure(logf LoggerFunc, network string, statsHouseAddr string, env string) {
+	c.configureEx(ConfigureArgs{
+		Logger:         logf,
+		Network:        network,
+		StatsHouseAddr: statsHouseAddr,
+		DefaultEnv:     env,
+	})
+}
+
+func (c *Client) configureEx(args ConfigureArgs) {
+	logf := args.Logger
 	if logf == nil {
 		logf = log.Printf
 	}
@@ -529,9 +562,10 @@ func (c *Client) configure(logf LoggerFunc, network string, statsHouseAddr strin
 	// then transport
 	c.transportMu.Lock()
 	defer c.transportMu.Unlock()
-	c.env = env
-	c.network = network
-	c.addr = statsHouseAddr
+	c.app = args.AppName
+	c.env = args.DefaultEnv
+	c.network = args.Network
+	c.addr = args.StatsHouseAddr
 	if c.conn != nil {
 		err := c.conn.Close()
 		if err != nil {
@@ -540,7 +574,7 @@ func (c *Client) configure(logf LoggerFunc, network string, statsHouseAddr strin
 		c.conn = nil
 	}
 
-	if maxSize := maxPayloadSize(network); maxSize != c.packet.maxSize {
+	if maxSize := maxPayloadSize(args.Network); maxSize != c.packet.maxSize {
 		c.packet = packet{
 			buf:     make([]byte, batchHeaderLen, maxSize),
 			maxSize: maxSize,
@@ -778,7 +812,7 @@ func (c *Client) flush() {
 	c.writeBatchHeader()
 
 	if c.conn == nil && c.addr != "" {
-		conn, err := c.netDial(c.env, c.network, c.addr)
+		conn, err := c.netDial(c.env, c.network, c.addr, c.app)
 		if err != nil {
 			c.rareLog("[statshouse] failed to dial statshouse: %v", err)
 		} else {