Merge pull request #74 from kradalby/deadlock-logging

Switch to a structured logger

README.md

@@ -119,6 +119,11 @@ Headscale's configuration file is named `config.json` or `config.yaml`. Headscal
 
 `server_url` is the external URL via which Headscale is reachable. `listen_addr` is the IP address and port the Headscale program should listen on. `ip_prefix` is the IP prefix (range) in which IP addresses for nodes will be allocated (default 100.64.0.0/10, e.g., 192.168.4.0/24, 10.0.0.0/8)
 
+```
+    "log_level": "debug"
+```
+`log_level` can be used to set the Log level for Headscale, it defaults to `debug`, and the available levels are: `trace`, `debug`, `info`, `warn` and `error`.
+
 ```
     "private_key_path": "private.key",
 ```

acls.go

@@ -4,11 +4,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"log"
 	"os"
 	"strconv"
 	"strings"
 
+	"github.com/rs/zerolog/log"
+
 	"github.com/tailscale/hujson"
 	"inet.af/netaddr"
 	"tailscale.com/tailcfg"
@@ -66,7 +67,8 @@ func (h *Headscale) generateACLRules() (*[]tailcfg.FilterRule, error) {
 		for j, u := range a.Users {
 			srcs, err := h.generateACLPolicySrcIP(u)
 			if err != nil {
-				log.Printf("Error parsing ACL %d, User %d", i, j)
+				log.Error().
+					Msgf("Error parsing ACL %d, User %d", i, j)
 				return nil, err
 			}
 			srcIPs = append(srcIPs, *srcs...)
@@ -77,7 +79,8 @@ func (h *Headscale) generateACLRules() (*[]tailcfg.FilterRule, error) {
 		for j, d := range a.Ports {
 			dests, err := h.generateACLPolicyDestPorts(d)
 			if err != nil {
-				log.Printf("Error parsing ACL %d, Port %d", i, j)
+				log.Error().
+					Msgf("Error parsing ACL %d, Port %d", i, j)
 				return nil, err
 			}
 			destPorts = append(destPorts, *dests...)

api.go

@@ -6,10 +6,11 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"net/http"
 	"time"
 
+	"github.com/rs/zerolog/log"
+
 	"github.com/gin-gonic/gin"
 	"github.com/klauspost/compress/zstd"
 	"gorm.io/datatypes"
@@ -63,21 +64,27 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 	mKeyStr := c.Param("id")
 	mKey, err := wgkey.ParseHex(mKeyStr)
 	if err != nil {
-		log.Printf("Cannot parse machine key: %s", err)
+		log.Error().
+			Str("handler", "Registration").
+			Err(err).
+			Msg("Cannot parse machine key")
 		c.String(http.StatusInternalServerError, "Sad!")
 		return
 	}
 	req := tailcfg.RegisterRequest{}
 	err = decode(body, &req, &mKey, h.privateKey)
 	if err != nil {
-		log.Printf("Cannot decode message: %s", err)
+		log.Error().
+			Str("handler", "Registration").
+			Err(err).
+			Msg("Cannot decode message")
 		c.String(http.StatusInternalServerError, "Very sad!")
 		return
 	}
 
 	var m Machine
 	if result := h.db.Preload("Namespace").First(&m, "machine_key = ?", mKey.HexString()); errors.Is(result.Error, gorm.ErrRecordNotFound) {
-		log.Println("New Machine!")
+		log.Info().Str("machine", req.Hostinfo.Hostname).Msg("New machine")
 		m = Machine{
 			Expiry:     &req.Expiry,
 			MachineKey: mKey.HexString(),
@@ -85,7 +92,10 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 			NodeKey:    wgkey.Key(req.NodeKey).HexString(),
 		}
 		if err := h.db.Create(&m).Error; err != nil {
-			log.Printf("Could not create row: %s", err)
+			log.Error().
+				Str("handler", "Registration").
+				Err(err).
+				Msg("Could not create row")
 			return
 		}
 	}
@@ -100,13 +110,20 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 	// We have the updated key!
 	if m.NodeKey == wgkey.Key(req.NodeKey).HexString() {
 		if m.Registered {
-			log.Printf("[%s] Client is registered and we have the current NodeKey. All clear to /map", m.Name)
+			log.Debug().
+				Str("handler", "Registration").
+				Str("machine", m.Name).
+				Msg("Client is registered and we have the current NodeKey. All clear to /mSending keepaliveap")
+
 			resp.AuthURL = ""
 			resp.MachineAuthorized = true
 			resp.User = *m.Namespace.toUser()
 			respBody, err := encode(resp, &mKey, h.privateKey)
 			if err != nil {
-				log.Printf("Cannot encode message: %s", err)
+				log.Error().
+					Str("handler", "Registration").
+					Err(err).
+					Msg("Cannot encode message")
 				c.String(http.StatusInternalServerError, "")
 				return
 			}
@@ -114,12 +131,18 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 			return
 		}
 
-		log.Printf("[%s] Not registered and not NodeKey rotation. Sending a authurl to register", m.Name)
+		log.Debug().
+			Str("handler", "Registration").
+			Str("machine", m.Name).
+			Msg("Not registered and not NodeKey rotation. Sending a authurl to register")
 		resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
 			h.cfg.ServerURL, mKey.HexString())
 		respBody, err := encode(resp, &mKey, h.privateKey)
 		if err != nil {
-			log.Printf("Cannot encode message: %s", err)
+			log.Error().
+				Str("handler", "Registration").
+				Err(err).
+				Msg("Cannot encode message")
 			c.String(http.StatusInternalServerError, "")
 			return
 		}
@@ -129,7 +152,10 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 
 	// The NodeKey we have matches OldNodeKey, which means this is a refresh after an key expiration
 	if m.NodeKey == wgkey.Key(req.OldNodeKey).HexString() {
-		log.Printf("[%s] We have the OldNodeKey in the database. This is a key refresh", m.Name)
+		log.Debug().
+			Str("handler", "Registration").
+			Str("machine", m.Name).
+			Msg("We have the OldNodeKey in the database. This is a key refresh")
 		m.NodeKey = wgkey.Key(req.NodeKey).HexString()
 		h.db.Save(&m)
 
@@ -137,7 +163,10 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 		resp.User = *m.Namespace.toUser()
 		respBody, err := encode(resp, &mKey, h.privateKey)
 		if err != nil {
-			log.Printf("Cannot encode message: %s", err)
+			log.Error().
+				Str("handler", "Registration").
+				Err(err).
+				Msg("Cannot encode message")
 			c.String(http.StatusInternalServerError, "Extremely sad!")
 			return
 		}
@@ -148,25 +177,38 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 	// We arrive here after a client is restarted without finalizing the authentication flow or
 	// when headscale is stopped in the middle of the auth process.
 	if m.Registered {
-		log.Printf("[%s] The node is sending us a new NodeKey, but machine is registered. All clear for /map", m.Name)
+		log.Debug().
+			Str("handler", "Registration").
+			Str("machine", m.Name).
+			Msg("The node is sending us a new NodeKey, but machine is registered. All clear for /map")
 		resp.AuthURL = ""
 		resp.MachineAuthorized = true
 		resp.User = *m.Namespace.toUser()
 		respBody, err := encode(resp, &mKey, h.privateKey)
 		if err != nil {
-			log.Printf("Cannot encode message: %s", err)
+			log.Error().
+				Str("handler", "Registration").
+				Err(err).
+				Msg("Cannot encode message")
 			c.String(http.StatusInternalServerError, "")
 			return
 		}
 		c.Data(200, "application/json; charset=utf-8", respBody)
 		return
 	}
-	log.Printf("[%s] The node is sending us a new NodeKey, sending auth url", m.Name)
+
+	log.Debug().
+		Str("handler", "Registration").
+		Str("machine", m.Name).
+		Msg("The node is sending us a new NodeKey, sending auth url")
 	resp.AuthURL = fmt.Sprintf("%s/register?key=%s",
 		h.cfg.ServerURL, mKey.HexString())
 	respBody, err := encode(resp, &mKey, h.privateKey)
 	if err != nil {
-		log.Printf("Cannot encode message: %s", err)
+		log.Error().
+			Str("handler", "Registration").
+			Err(err).
+			Msg("Cannot encode message")
 		c.String(http.StatusInternalServerError, "")
 		return
 	}
@@ -183,28 +225,45 @@ func (h *Headscale) RegistrationHandler(c *gin.Context) {
 //
 // At this moment the updates are sent in a quite horrendous way, but they kinda work.
 func (h *Headscale) PollNetMapHandler(c *gin.Context) {
+	log.Trace().
+		Str("handler", "PollNetMap").
+		Str("id", c.Param("id")).
+		Msg("PollNetMapHandler called")
 	body, _ := io.ReadAll(c.Request.Body)
 	mKeyStr := c.Param("id")
 	mKey, err := wgkey.ParseHex(mKeyStr)
 	if err != nil {
-		log.Printf("Cannot parse client key: %s", err)
+		log.Error().
+			Str("handler", "PollNetMap").
+			Err(err).
+			Msg("Cannot parse client key")
 		c.String(http.StatusBadRequest, "")
 		return
 	}
 	req := tailcfg.MapRequest{}
 	err = decode(body, &req, &mKey, h.privateKey)
 	if err != nil {
-		log.Printf("Cannot decode message: %s", err)
+		log.Error().
+			Str("handler", "PollNetMap").
+			Err(err).
+			Msg("Cannot decode message")
 		c.String(http.StatusBadRequest, "")
 		return
 	}
 
 	var m Machine
 	if result := h.db.Preload("Namespace").First(&m, "machine_key = ?", mKey.HexString()); errors.Is(result.Error, gorm.ErrRecordNotFound) {
-		log.Printf("Ignoring request, cannot find machine with key %s", mKey.HexString())
+		log.Warn().
+			Str("handler", "PollNetMap").
+			Msgf("Ignoring request, cannot find machine with key %s", mKey.HexString())
 		c.String(http.StatusUnauthorized, "")
 		return
 	}
+	log.Trace().
+		Str("handler", "PollNetMap").
+		Str("id", c.Param("id")).
+		Str("machine", m.Name).
+		Msg("Found machine in database")
 
 	hostinfo, _ := json.Marshal(req.Hostinfo)
 	m.Name = req.Hostinfo.Hostname
@@ -227,17 +286,36 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
 	}
 	h.db.Save(&m)
 
-	pollData := make(chan []byte, 1)
 	update := make(chan []byte, 1)
-	cancelKeepAlive := make(chan []byte, 1)
+
+	pollData := make(chan []byte, 1)
 	defer close(pollData)
+
+	cancelKeepAlive := make(chan []byte, 1)
 	defer close(cancelKeepAlive)
+
+	log.Trace().
+		Str("handler", "PollNetMap").
+		Str("id", c.Param("id")).
+		Str("machine", m.Name).
+		Msg("Locking poll mutex")
 	h.pollMu.Lock()
 	h.clientsPolling[m.ID] = update
 	h.pollMu.Unlock()
+	log.Trace().
+		Str("handler", "PollNetMap").
+		Str("id", c.Param("id")).
+		Str("machine", m.Name).
+		Msg("Unlocking poll mutex")
 
 	data, err := h.getMapResponse(mKey, req, m)
 	if err != nil {
+		log.Error().
+			Str("handler", "PollNetMap").
+			Str("id", c.Param("id")).
+			Str("machine", m.Name).
+			Err(err).
+			Msg("Failed to get Map response")
 		c.String(http.StatusInternalServerError, ":(")
 		return
 	}
@@ -247,37 +325,71 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
 	// empty endpoints to peers)
 
 	// Details on the protocol can be found in https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go#L696
-	log.Printf("[%s] ReadOnly=%t   OmitPeers=%t    Stream=%t", m.Name, req.ReadOnly, req.OmitPeers, req.Stream)
+	log.Debug().
+		Str("handler", "PollNetMap").
+		Str("id", c.Param("id")).
+		Str("machine", m.Name).
+		Bool("readOnly", req.ReadOnly).
+		Bool("omitPeers", req.OmitPeers).
+		Bool("stream", req.Stream).
+		Msg("Client map request processed")
 
 	if req.ReadOnly {
-		log.Printf("[%s] Client is starting up. Asking for DERP map", m.Name)
+		log.Info().
+			Str("handler", "PollNetMap").
+			Str("machine", m.Name).
+			Msg("Client is starting up. Asking for DERP map")
 		c.Data(200, "application/json; charset=utf-8", *data)
 		return
 	}
 	if req.OmitPeers && !req.Stream {
-		log.Printf("[%s] Client sent endpoint update and is ok with a response without peer list", m.Name)
+		log.Info().
+			Str("handler", "PollNetMap").
+			Str("machine", m.Name).
+			Msg("Client sent endpoint update and is ok with a response without peer list")
 		c.Data(200, "application/json; charset=utf-8", *data)
 		return
 	} else if req.OmitPeers && req.Stream {
-		log.Printf("[%s] Warning, ignoring request, don't know how to handle it", m.Name)
+		log.Warn().
+			Str("handler", "PollNetMap").
+			Str("machine", m.Name).
+			Msg("Ignoring request, don't know how to handle it")
 		c.String(http.StatusBadRequest, "")
 		return
 	}
 
-	log.Printf("[%s] Client is ready to access the tailnet", m.Name)
+	log.Info().
-	log.Printf("[%s] Sending initial map", m.Name)
+		Str("handler", "PollNetMap").
+		Str("machine", m.Name).
+		Msg("Client is ready to access the tailnet")
+	log.Info().
+		Str("handler", "PollNetMap").
+		Str("machine", m.Name).
+		Msg("Sending initial map")
 	pollData <- *data
 
-	log.Printf("[%s] Notifying peers", m.Name)
+	log.Info().
+		Str("handler", "PollNetMap").
+		Str("machine", m.Name).
+		Msg("Notifying peers")
 	peers, _ := h.getPeers(m)
 	h.pollMu.Lock()
 	for _, p := range *peers {
 		pUp, ok := h.clientsPolling[uint64(p.ID)]
 		if ok {
-			log.Printf("[%s] Notifying peer %s (%s)", m.Name, p.Name, p.Addresses[0])
+			log.Info().
+				Str("handler", "PollNetMap").
+				Str("machine", m.Name).
+				Str("peer", m.Name).
+				Str("address", p.Addresses[0].String()).
+				Msgf("Notifying peer %s (%s)", p.Name, p.Addresses[0])
 			pUp <- []byte{}
 		} else {
-			log.Printf("[%s] Peer %s does not appear to be polling", m.Name, p.Name)
+			log.Info().
+				Str("handler", "PollNetMap").
+				Str("machine", m.Name).
+				Str("peer", m.Name).
+				Msgf("Peer %s does not appear to be polling", p.Name)
 		}
 	}
 	h.pollMu.Unlock()
@@ -287,10 +399,18 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
 	c.Stream(func(w io.Writer) bool {
 		select {
 		case data := <-pollData:
-			log.Printf("[%s] Sending data (%d bytes)", m.Name, len(data))
+			log.Trace().
+				Str("handler", "PollNetMap").
+				Str("machine", m.Name).
+				Int("bytes", len(data)).
+				Msg("Sending data")
 			_, err := w.Write(data)
 			if err != nil {
-				log.Printf("[%s] Cannot write data: %s", m.Name, err)
+				log.Error().
+					Str("handler", "PollNetMap").
+					Str("machine", m.Name).
+					Err(err).
+					Msg("Cannot write data")
 			}
 			now := time.Now().UTC()
 			m.LastSeen = &now
@@ -298,19 +418,33 @@ func (h *Headscale) PollNetMapHandler(c *gin.Context) {
 			return true
 
 		case <-update:
-			log.Printf("[%s] Received a request for update", m.Name)
+			log.Debug().
+				Str("handler", "PollNetMap").
+				Str("machine", m.Name).
+				Msg("Received a request for update")
 			data, err := h.getMapResponse(mKey, req, m)
 			if err != nil {
-				log.Printf("[%s] Could not get the map update: %s", m.Name, err)
+				log.Error().
+					Str("handler", "PollNetMap").
+					Str("machine", m.Name).
+					Err(err).
+					Msg("Could not get the map update")
 			}
 			_, err = w.Write(*data)
 			if err != nil {
-				log.Printf("[%s] Could not write the map response: %s", m.Name, err)
+				log.Error().
+					Str("handler", "PollNetMap").
+					Str("machine", m.Name).
+					Err(err).
+					Msg("Could not write the map response")
 			}
 			return true
 
 		case <-c.Request.Context().Done():
-			log.Printf("[%s] The client has closed the connection", m.Name)
+			log.Info().
+				Str("handler", "PollNetMap").
+				Str("machine", m.Name).
+				Msg("The client has closed the connection")
 			now := time.Now().UTC()
 			m.LastSeen = &now
 			h.db.Save(&m)
@@ -335,10 +469,16 @@ func (h *Headscale) keepAlive(cancel chan []byte, pollData chan []byte, mKey wgk
 			h.pollMu.Lock()
 			data, err := h.getMapKeepAliveResponse(mKey, req, m)
 			if err != nil {
-				log.Printf("Error generating the keep alive msg: %s", err)
+				log.Error().
+					Str("func", "keepAlive").
+					Err(err).
+					Msg("Error generating the keep alive msg")
 				return
 			}
-			log.Printf("[%s] Sending keepalive", m.Name)
+			log.Debug().
+				Str("func", "keepAlive").
+				Str("machine", m.Name).
+				Msg("Sending keepalive")
 			pollData <- *data
 			h.pollMu.Unlock()
 			time.Sleep(60 * time.Second)
@@ -347,14 +487,24 @@ func (h *Headscale) keepAlive(cancel chan []byte, pollData chan []byte, mKey wgk
 }
 
 func (h *Headscale) getMapResponse(mKey wgkey.Key, req tailcfg.MapRequest, m Machine) (*[]byte, error) {
+	log.Trace().
+		Str("func", "getMapResponse").
+		Str("machine", req.Hostinfo.Hostname).
+		Msg("Creating Map response")
 	node, err := m.toNode()
 	if err != nil {
-		log.Printf("Cannot convert to node: %s", err)
+		log.Error().
+			Str("func", "getMapResponse").
+			Err(err).
+			Msg("Cannot convert to node")
 		return nil, err
 	}
 	peers, err := h.getPeers(m)
 	if err != nil {
-		log.Printf("Cannot fetch peers: %s", err)
+		log.Error().
+			Str("func", "getMapResponse").
+			Err(err).
+			Msg("Cannot fetch peers")
 		return nil, err
 	}
 
@@ -426,26 +576,49 @@ func (h *Headscale) getMapKeepAliveResponse(mKey wgkey.Key, req tailcfg.MapReque
 }
 
 func (h *Headscale) handleAuthKey(c *gin.Context, db *gorm.DB, idKey wgkey.Key, req tailcfg.RegisterRequest, m Machine) {
+	log.Debug().
+		Str("func", "handleAuthKey").
+		Str("machine", req.Hostinfo.Hostname).
+		Msgf("Processing auth key for %s", req.Hostinfo.Hostname)
 	resp := tailcfg.RegisterResponse{}
 	pak, err := h.checkKeyValidity(req.Auth.AuthKey)
 	if err != nil {
 		resp.MachineAuthorized = false
 		respBody, err := encode(resp, &idKey, h.privateKey)
 		if err != nil {
-			log.Printf("Cannot encode message: %s", err)
+			log.Error().
+				Str("func", "handleAuthKey").
+				Str("machine", m.Name).
+				Err(err).
+				Msg("Cannot encode message")
 			c.String(http.StatusInternalServerError, "")
 			return
 		}
 		c.Data(200, "application/json; charset=utf-8", respBody)
-		log.Printf("[%s] Failed authentication via AuthKey", m.Name)
+		log.Error().
+			Str("func", "handleAuthKey").
+			Str("machine", m.Name).
+			Msg("Failed authentication via AuthKey")
 		return
 	}
+
+	log.Debug().
+		Str("func", "handleAuthKey").
+		Str("machine", m.Name).
+		Msg("Authentication key was valid, proceeding to acquire an IP address")
 	ip, err := h.getAvailableIP()
 	if err != nil {
-		log.Println(err)
+		log.Error().
+			Str("func", "handleAuthKey").
+			Str("machine", m.Name).
+			Msg("Failed to find an available IP")
 		return
 	}
-	log.Printf("Assigning %s to %s", ip, m.Name)
+	log.Info().
+		Str("func", "handleAuthKey").
+		Str("machine", m.Name).
+		Str("ip", ip.String()).
+		Msgf("Assining %s to %s", ip, m.Name)
 
 	m.AuthKeyID = uint(pak.ID)
 	m.IPAddress = ip.String()
@@ -459,10 +632,18 @@ func (h *Headscale) handleAuthKey(c *gin.Context, db *gorm.DB, idKey wgkey.Key,
 	resp.User = *pak.Namespace.toUser()
 	respBody, err := encode(resp, &idKey, h.privateKey)
 	if err != nil {
-		log.Printf("Cannot encode message: %s", err)
+		log.Error().
+			Str("func", "handleAuthKey").
+			Str("machine", m.Name).
+			Err(err).
+			Msg("Cannot encode message")
 		c.String(http.StatusInternalServerError, "Extremely sad!")
 		return
 	}
 	c.Data(200, "application/json; charset=utf-8", respBody)
-	log.Printf("[%s] Successfully authenticated via AuthKey", m.Name)
+	log.Info().
+		Str("func", "handleAuthKey").
+		Str("machine", m.Name).
+		Str("ip", ip.String()).
+		Msg("Successfully authenticated via AuthKey")
 }

app.go

@@ -3,13 +3,14 @@ package headscale
 import (
 	"errors"
 	"fmt"
-	"log"
 	"net/http"
 	"os"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/rs/zerolog/log"
+
 	"github.com/gin-gonic/gin"
 	"golang.org/x/crypto/acme/autocert"
 	"gorm.io/gorm"
@@ -120,21 +121,21 @@ func (h *Headscale) ExpireEphemeralNodes(milliSeconds int64) {
 func (h *Headscale) expireEphemeralNodesWorker() {
 	namespaces, err := h.ListNamespaces()
 	if err != nil {
-		log.Printf("Error listing namespaces: %s", err)
+		log.Error().Err(err).Msg("Error listing namespaces")
 		return
 	}
 	for _, ns := range *namespaces {
 		machines, err := h.ListMachinesInNamespace(ns.Name)
 		if err != nil {
-			log.Printf("Error listing machines in namespace %s: %s", ns.Name, err)
+			log.Error().Err(err).Str("namespace", ns.Name).Msg("Error listing machines in namespace")
 			return
 		}
 		for _, m := range *machines {
 			if m.AuthKey != nil && m.LastSeen != nil && m.AuthKey.Ephemeral && time.Now().After(m.LastSeen.Add(h.cfg.EphemeralNodeInactivityTimeout)) {
-				log.Printf("[%s] Ephemeral client removed from database\n", m.Name)
+				log.Info().Str("machine", m.Name).Msg("Ephemeral client removed from database")
 				err = h.db.Unscoped().Delete(m).Error
 				if err != nil {
-					log.Printf("[%s] 🤮 Cannot delete ephemeral machine from the database: %s", m.Name, err)
+					log.Error().Err(err).Str("machine", m.Name).Msg("🤮 Cannot delete ephemeral machine from the database")
 				}
 			}
 		}
@@ -168,7 +169,7 @@ func (h *Headscale) Serve() error {
 
 	if h.cfg.TLSLetsEncryptHostname != "" {
 		if !strings.HasPrefix(h.cfg.ServerURL, "https://") {
-			log.Println("WARNING: listening with TLS but ServerURL does not start with https://")
+			log.Warn().Msg("Listening with TLS but ServerURL does not start with https://")
 		}
 
 		m := autocert.Manager{
@@ -191,7 +192,10 @@ func (h *Headscale) Serve() error {
 			// port 80 for the certificate validation in addition to the headscale
 			// service, which can be configured to run on any other port.
 			go func() {
-				log.Fatal(http.ListenAndServe(h.cfg.TLSLetsEncryptListen, m.HTTPHandler(http.HandlerFunc(h.redirect))))
+
+				log.Fatal().
+					Err(http.ListenAndServe(h.cfg.TLSLetsEncryptListen, m.HTTPHandler(http.HandlerFunc(h.redirect)))).
+					Msg("failed to set up a HTTP server")
 			}()
 			err = s.ListenAndServeTLS("", "")
 		} else {
@@ -199,12 +203,12 @@ func (h *Headscale) Serve() error {
 		}
 	} else if h.cfg.TLSCertPath == "" {
 		if !strings.HasPrefix(h.cfg.ServerURL, "http://") {
-			log.Println("WARNING: listening without TLS but ServerURL does not start with http://")
+			log.Warn().Msg("Listening without TLS but ServerURL does not start with http://")
 		}
 		err = r.Run(h.cfg.Addr)
 	} else {
 		if !strings.HasPrefix(h.cfg.ServerURL, "https://") {
-			log.Println("WARNING: listening with TLS but ServerURL does not start with https://")
+			log.Warn().Msg("Listening with TLS but ServerURL does not start with https://")
 		}
 		err = r.RunTLS(h.cfg.Addr, h.cfg.TLSCertPath, h.cfg.TLSKeyPath)
 	}

cmd/headscale/cli/root.go

@@ -2,8 +2,9 @@ package cli
 
 import (
 	"fmt"
-	"github.com/spf13/cobra"
 	"os"
+
+	"github.com/spf13/cobra"
 )
 
 func init() {
@@ -17,7 +18,7 @@ var rootCmd = &cobra.Command{
 headscale is an open source implementation of the Tailscale control server
 
 Juan Font Alonso <juanfontalonso@gmail.com> - 2021
-https://gitlab.com/juanfont/headscale`,
+https://github.com/juanfont/headscale`,
 }
 
 func Execute() {

cmd/headscale/cli/utils.go

@@ -5,13 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"os"
 	"path/filepath"
 	"strings"
 	"time"
 
 	"github.com/juanfont/headscale"
+	"github.com/rs/zerolog/log"
 	"github.com/spf13/viper"
 	"gopkg.in/yaml.v2"
 	"inet.af/netaddr"
@@ -39,6 +39,8 @@ func LoadConfig(path string) error {
 
 	viper.SetDefault("ip_prefix", "100.64.0.0/10")
 
+	viper.SetDefault("log_level", "debug")
+
 	err := viper.ReadInConfig()
 	if err != nil {
 		return fmt.Errorf("Fatal error reading config file: %s \n", err)
@@ -52,7 +54,8 @@ func LoadConfig(path string) error {
 
 	if (viper.GetString("tls_letsencrypt_hostname") != "") && (viper.GetString("tls_letsencrypt_challenge_type") == "TLS-ALPN-01") && (!strings.HasSuffix(viper.GetString("listen_addr"), ":443")) {
 		// this is only a warning because there could be something sitting in front of headscale that redirects the traffic (e.g. an iptables rule)
-		log.Println("Warning: when using tls_letsencrypt_hostname with TLS-ALPN-01 as challenge type, headscale must be reachable on port 443, i.e. listen_addr should probably end in :443")
+		log.Warn().
+			Msg("Warning: when using tls_letsencrypt_hostname with TLS-ALPN-01 as challenge type, headscale must be reachable on port 443, i.e. listen_addr should probably end in :443")
 	}
 
 	if (viper.GetString("tls_letsencrypt_challenge_type") != "HTTP-01") && (viper.GetString("tls_letsencrypt_challenge_type") != "TLS-ALPN-01") {
@@ -82,9 +85,13 @@ func absPath(path string) string {
 }
 
 func getHeadscaleApp() (*headscale.Headscale, error) {
-	derpMap, err := loadDerpMap(absPath(viper.GetString("derp_map_path")))
+	derpPath := absPath(viper.GetString("derp_map_path"))
+	derpMap, err := loadDerpMap(derpPath)
 	if err != nil {
-		log.Printf("Could not load DERP servers map file: %s", err)
+		log.Error().
+			Str("path", derpPath).
+			Err(err).
+			Msg("Could not load DERP servers map file")
 	}
 
 	// Minimum inactivity time out is keepalive timeout (60s) plus a few seconds
@@ -129,9 +136,13 @@ func getHeadscaleApp() (*headscale.Headscale, error) {
 	// We are doing this here, as in the future could be cool to have it also hot-reload
 
 	if viper.GetString("acl_policy_path") != "" {
-		err = h.LoadACLPolicy(absPath(viper.GetString("acl_policy_path")))
+		aclPath := absPath(viper.GetString("acl_policy_path"))
+		err = h.LoadACLPolicy(aclPath)
 		if err != nil {
-			log.Printf("Could not load the ACL policy: %s", err)
+			log.Error().
+				Str("path", aclPath).
+				Err(err).
+				Msg("Could not load the ACL policy")
 		}
 	}
 
@@ -161,24 +172,24 @@ func JsonOutput(result interface{}, errResult error, outputFormat string) {
 		if errResult != nil {
 			j, err = json.MarshalIndent(ErrorOutput{errResult.Error()}, "", "\t")
 			if err != nil {
-				log.Fatalln(err)
+				log.Fatal().Err(err)
 			}
 		} else {
 			j, err = json.MarshalIndent(result, "", "\t")
 			if err != nil {
-				log.Fatalln(err)
+				log.Fatal().Err(err)
 			}
 		}
 	case "json-line":
 		if errResult != nil {
 			j, err = json.Marshal(ErrorOutput{errResult.Error()})
 			if err != nil {
-				log.Fatalln(err)
+				log.Fatal().Err(err)
 			}
 		} else {
 			j, err = json.Marshal(result)
 			if err != nil {
-				log.Fatalln(err)
+				log.Fatal().Err(err)
 			}
 		}
 	}

cmd/headscale/headscale.go

@@ -1,15 +1,41 @@
 package main
 
 import (
-	"log"
+	"os"
+	"time"
 
 	"github.com/juanfont/headscale/cmd/headscale/cli"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"github.com/spf13/viper"
 )
 
 func main() {
+	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+	log.Logger = log.Output(zerolog.ConsoleWriter{
+		Out:        os.Stdout,
+		TimeFormat: time.RFC3339,
+	})
+
 	err := cli.LoadConfig("")
 	if err != nil {
-		log.Fatalf(err.Error())
+		log.Fatal().Err(err)
+	}
+
+	logLevel := viper.GetString("log_level")
+	switch logLevel {
+	case "trace":
+		zerolog.SetGlobalLevel(zerolog.TraceLevel)
+	case "debug":
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	case "info":
+		zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	case "warn":
+		zerolog.SetGlobalLevel(zerolog.WarnLevel)
+	case "error":
+		zerolog.SetGlobalLevel(zerolog.ErrorLevel)
+	default:
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
 	}
 
 	cli.Execute()

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/klauspost/compress v1.13.1
 	github.com/lib/pq v1.10.2 // indirect
 	github.com/mattn/go-sqlite3 v1.14.7 // indirect
+	github.com/rs/zerolog v1.23.0 // indirect
 	github.com/spf13/cobra v1.1.3
 	github.com/spf13/viper v1.8.1
 	github.com/tailscale/hujson v0.0.0-20200924210142-dde312d0d6a2

go.sum

@@ -683,6 +683,8 @@ github.com/rogpeppe/go-internal v1.6.2/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTE
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/zerolog v1.13.0/go.mod h1:YbFCdg8HfsridGWAh22vktObvhZbQsZXe4/zB0OKkWU=
 github.com/rs/zerolog v1.15.0/go.mod h1:xYTKnLHcpfU2225ny5qZjxnj9NvkumZYjJHlAThCjNc=
+github.com/rs/zerolog v1.23.0 h1:UskrK+saS9P9Y789yNNulYKdARjPZuS35B8gJF2x60g=
+github.com/rs/zerolog v1.23.0/go.mod h1:6c7hFfxPOy7TacJc4Fcdi24/J0NKYGzjG8FWRI916Qo=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryancurrah/gomodguard v1.1.0/go.mod h1:4O8tr7hBODaGE6VIhfJDHcwzh5GUccKSJBU0UMXJFVM=
 github.com/ryanrolds/sqlclosecheck v0.3.0/go.mod h1:1gREqxyTGR3lVtpngyFo3hZAgk0KCtEdgEkHwDbigdA=

machine.go

@@ -3,11 +3,12 @@ package headscale
 import (
 	"encoding/json"
 	"fmt"
-	"log"
 	"sort"
 	"strconv"
 	"time"
 
+	"github.com/rs/zerolog/log"
+
 	"gorm.io/datatypes"
 	"inet.af/netaddr"
 	"tailscale.com/tailcfg"
@@ -157,7 +158,7 @@ func (h *Headscale) getPeers(m Machine) (*[]*tailcfg.Node, error) {
 	machines := []Machine{}
 	if err := h.db.Where("namespace_id = ? AND machine_key <> ? AND registered",
 		m.NamespaceID, m.MachineKey).Find(&machines).Error; err != nil {
-		log.Printf("Error accessing db: %s", err)
+		log.Error().Err(err).Msg("Error accessing db")
 		return nil, err
 	}
 

namespaces.go

@@ -4,9 +4,9 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"log"
 	"time"
 
+	"github.com/rs/zerolog/log"
 	"gorm.io/gorm"
 	"tailscale.com/tailcfg"
 )
@@ -33,7 +33,10 @@ func (h *Headscale) CreateNamespace(name string) (*Namespace, error) {
 	}
 	n.Name = name
 	if err := h.db.Create(&n).Error; err != nil {
-		log.Printf("Could not create row: %s", err)
+		log.Error().
+			Str("func", "CreateNamespace").
+			Err(err).
+			Msg("Could not create row")
 		return nil, err
 	}
 	return &n, nil
@@ -133,7 +136,10 @@ func (h *Headscale) RequestMapUpdates(namespaceID uint) error {
 	names = append(names, namespace.Name)
 	data, err := json.Marshal(names)
 	if err != nil {
-		log.Printf("Could not marshal namespaces_pending_updates: %s", err)
+		log.Error().
+			Str("func", "RequestMapUpdates").
+			Err(err).
+			Msg("Could not marshal namespaces_pending_updates")
 		return err
 	}
 	return h.setValue("namespaces_pending_updates", string(data))
@@ -154,7 +160,10 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
 		return
 	}
 	for _, name := range names {
-		log.Printf("Sending updates to nodes in namespace %s", name)
+		log.Trace().
+			Str("func", "RequestMapUpdates").
+			Str("machine", name).
+			Msg("Sending updates to nodes in namespace")
 		machines, err := h.ListMachinesInNamespace(name)
 		if err != nil {
 			continue
@@ -165,10 +174,19 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
 			for _, p := range *peers {
 				pUp, ok := h.clientsPolling[uint64(p.ID)]
 				if ok {
-					log.Printf("[%s] Notifying peer %s (%s)", m.Name, p.Name, p.Addresses[0])
+					log.Info().
+						Str("func", "checkForNamespacesPendingUpdates").
+						Str("machine", m.Name).
+						Str("peer", m.Name).
+						Str("address", p.Addresses[0].String()).
+						Msgf("Notifying peer %s (%s)", p.Name, p.Addresses[0])
 					pUp <- []byte{}
 				} else {
-					log.Printf("[%s] Peer %s does not appear to be polling", m.Name, p.Name)
+					log.Info().
+						Str("func", "checkForNamespacesPendingUpdates").
+						Str("machine", m.Name).
+						Str("peer", m.Name).
+						Msgf("Peer %s does not appear to be polling", p.Name)
 				}
 			}
 			h.pollMu.Unlock()
@@ -181,7 +199,10 @@ func (h *Headscale) checkForNamespacesPendingUpdates() {
 	if v == newV { // only clear when no changes, so we notified everybody
 		err = h.setValue("namespaces_pending_updates", "")
 		if err != nil {
-			log.Printf("Could not save to KV: %s", err)
+			log.Error().
+				Str("func", "checkForNamespacesPendingUpdates").
+				Err(err).
+				Msg("Could not save to KV")
 			return
 		}
 	}