state: introduce state

this commit moves all of the read and write logic, and all different parts
of headscale that manages some sort of persistent and in memory state into
a separate package.

The goal of this is to clearly define the boundry between parts of the app
which accesses and modifies data, and where it happens. Previously, different
state (routes, policy, db and so on) was used directly, and sometime passed to
functions as pointers.

Now all access has to go through state. In the initial implementation,
most of the same functions exists and have just been moved. In the future
centralising this will allow us to optimise bottle necks with the database
(in memory state) and make the different parts talking to eachother do so
in the same way across headscale components.

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

hscontrol/mapper/mapper.go

@@ -16,10 +16,9 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/juanfont/headscale/hscontrol/db"
 	"github.com/juanfont/headscale/hscontrol/notifier"
 	"github.com/juanfont/headscale/hscontrol/policy"
-	"github.com/juanfont/headscale/hscontrol/routes"
+	"github.com/juanfont/headscale/hscontrol/state"
 	"github.com/juanfont/headscale/hscontrol/types"
 	"github.com/juanfont/headscale/hscontrol/util"
 	"github.com/klauspost/compress/zstd"
@@ -52,13 +51,9 @@ var debugDumpMapResponsePath = envknob.String("HEADSCALE_DEBUG_DUMP_MAPRESPONSE_
 
 type Mapper struct {
 	// Configuration
-	// TODO(kradalby): figure out if this is the format we want this in
-	db      *db.HSDatabase
-	cfg     *types.Config
-	derpMap *tailcfg.DERPMap
-	notif   *notifier.Notifier
-	polMan  policy.PolicyManager
-	primary *routes.PrimaryRoutes
+	state *state.State
+	cfg   *types.Config
+	notif *notifier.Notifier
 
 	uid     string
 	created time.Time
@@ -71,22 +66,16 @@ type patch struct {
 }
 
 func NewMapper(
-	db *db.HSDatabase,
+	state *state.State,
 	cfg *types.Config,
-	derpMap *tailcfg.DERPMap,
 	notif *notifier.Notifier,
-	polMan policy.PolicyManager,
-	primary *routes.PrimaryRoutes,
 ) *Mapper {
 	uid, _ := util.GenerateRandomStringDNSSafe(mapperIDLength)
 
 	return &Mapper{
-		db:      db,
-		cfg:     cfg,
-		derpMap: derpMap,
-		notif:   notif,
-		polMan:  polMan,
-		primary: primary,
+		state: state,
+		cfg:   cfg,
+		notif: notif,
 
 		uid:     uid,
 		created: time.Now(),
@@ -177,8 +166,7 @@ func (m *Mapper) fullMapResponse(
 	err = appendPeerChanges(
 		resp,
 		true, // full change
-		m.polMan,
-		m.primary,
+		m.state,
 		node,
 		capVer,
 		peers,
@@ -241,8 +229,6 @@ func (m *Mapper) DERPMapResponse(
 	node *types.Node,
 	derpMap *tailcfg.DERPMap,
 ) ([]byte, error) {
-	m.derpMap = derpMap
-
 	resp := m.baseMapResponse()
 	resp.DERPMap = derpMap
 
@@ -281,8 +267,7 @@ func (m *Mapper) PeerChangedResponse(
 	err = appendPeerChanges(
 		&resp,
 		false, // partial change
-		m.polMan,
-		m.primary,
+		m.state,
 		node,
 		mapRequest.Version,
 		changedNodes,
@@ -309,13 +294,13 @@ func (m *Mapper) PeerChangedResponse(
 		resp.PeersChangedPatch = patches
 	}
 
-	_, matchers := m.polMan.Filter()
+	_, matchers := m.state.Filter()
 	// Add the node itself, it might have changed, and particularly
 	// if there are no patches or changes, this is a self update.
 	tailnode, err := tailNode(
-		node, mapRequest.Version, m.polMan,
+		node, mapRequest.Version, m.state,
 		func(id types.NodeID) []netip.Prefix {
-			return policy.ReduceRoutes(node, m.primary.PrimaryRoutes(id), matchers)
+			return policy.ReduceRoutes(node, m.state.GetNodePrimaryRoutes(id), matchers)
 		},
 		m.cfg)
 	if err != nil {
@@ -464,11 +449,11 @@ func (m *Mapper) baseWithConfigMapResponse(
 ) (*tailcfg.MapResponse, error) {
 	resp := m.baseMapResponse()
 
-	_, matchers := m.polMan.Filter()
+	_, matchers := m.state.Filter()
 	tailnode, err := tailNode(
-		node, capVer, m.polMan,
+		node, capVer, m.state,
 		func(id types.NodeID) []netip.Prefix {
-			return policy.ReduceRoutes(node, m.primary.PrimaryRoutes(id), matchers)
+			return policy.ReduceRoutes(node, m.state.GetNodePrimaryRoutes(id), matchers)
 		},
 		m.cfg)
 	if err != nil {
@@ -476,7 +461,7 @@ func (m *Mapper) baseWithConfigMapResponse(
 	}
 	resp.Node = tailnode
 
-	resp.DERPMap = m.derpMap
+	resp.DERPMap = m.state.DERPMap()
 
 	resp.Domain = m.cfg.Domain()
 
@@ -497,7 +482,7 @@ func (m *Mapper) baseWithConfigMapResponse(
 // If no peer IDs are given, all peers are returned.
 // If at least one peer ID is given, only these peer nodes will be returned.
 func (m *Mapper) ListPeers(nodeID types.NodeID, peerIDs ...types.NodeID) (types.Nodes, error) {
-	peers, err := m.db.ListPeers(nodeID, peerIDs...)
+	peers, err := m.state.ListPeers(nodeID, peerIDs...)
 	if err != nil {
 		return nil, err
 	}
@@ -513,7 +498,7 @@ func (m *Mapper) ListPeers(nodeID types.NodeID, peerIDs ...types.NodeID) (types.
 // ListNodes queries the database for either all nodes if no parameters are given
 // or for the given nodes if at least one node ID is given as parameter
 func (m *Mapper) ListNodes(nodeIDs ...types.NodeID) (types.Nodes, error) {
-	nodes, err := m.db.ListNodes(nodeIDs...)
+	nodes, err := m.state.ListNodes(nodeIDs...)
 	if err != nil {
 		return nil, err
 	}
@@ -537,16 +522,15 @@ func appendPeerChanges(
 	resp *tailcfg.MapResponse,
 
 	fullChange bool,
-	polMan policy.PolicyManager,
-	primary *routes.PrimaryRoutes,
+	state *state.State,
 	node *types.Node,
 	capVer tailcfg.CapabilityVersion,
 	changed types.Nodes,
 	cfg *types.Config,
 ) error {
-	filter, matchers := polMan.Filter()
+	filter, matchers := state.Filter()
 
-	sshPolicy, err := polMan.SSHPolicy(node)
+	sshPolicy, err := state.SSHPolicy(node)
 	if err != nil {
 		return err
 	}
@@ -562,9 +546,9 @@ func appendPeerChanges(
 	dnsConfig := generateDNSConfig(cfg, node)
 
 	tailPeers, err := tailNodes(
-		changed, capVer, polMan,
+		changed, capVer, state,
 		func(id types.NodeID) []netip.Prefix {
-			return policy.ReduceRoutes(node, primary.PrimaryRoutes(id), matchers)
+			return policy.ReduceRoutes(node, state.GetNodePrimaryRoutes(id), matchers)
 		},
 		cfg)
 	if err != nil {