webnet/tailscale
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ipn/ipnlocal: allow retrieval of serve config ETags from local API

Browse Source 
This change adds API to ipn.LocalBackend to retrieve the ETag when
querying for the current serve config. This allows consumers of
ipn.LocalBackend.SetServeConfig to utilize the concurrency control
offered by ETags. Previous to this change, utilizing serve config ETags
required copying the local backend's internal ETag calcuation.

The local API server was previously copying the local backend's ETag
calculation as described above. With this change, the local API server
now uses the new ETag retrieval function instead. Serve config ETags are
therefore now opaque to clients, in line with best practices.

Fixes tailscale/corp#35857
Signed-off-by: Harry Harpham <harry@tailscale.com>
This commit is contained in:
Harry Harpham
2026-01-13 14:26:20 -07:00
parent 643e91f2eb
commit 1b88e93ff5
3 changed files with 48 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files
ipn/ipnlocal/serve_test.go
+17 -22
View File
@@ -9,9 +9,7 @@ import (
"bytes"
"cmp"
"context"
"crypto/sha256"
"crypto/tls"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
@@ -222,16 +220,6 @@ func TestGetServeHandler(t *testing.T) {
}
}
func getEtag(t *testing.T, b any) string {
t.Helper()
bts, err := json.Marshal(b)
if err != nil {
t.Fatal(err)
}
sum := sha256.Sum256(bts)
return hex.EncodeToString(sum[:])
}
// TestServeConfigForeground tests the inter-dependency
// between a ServeConfig and a WatchIPNBus:
// 1. Creating a WatchIPNBus returns a sessionID, that
@@ -544,8 +532,14 @@ func TestServeConfigServices(t *testing.T) {
func TestServeConfigETag(t *testing.T) {
b := newTestBackend(t)
// a nil config with initial etag should succeed
err := b.SetServeConfig(nil, getEtag(t, nil))
// the etag should be valid even when there is no config
_, emptyStateETag, err := b.ServeConfigETag()
if err != nil {
t.Fatal(err)
}
// a nil config with the empty-state etag should succeed
err = b.SetServeConfig(nil, emptyStateETag)
if err != nil {
t.Fatal(err)
}
@@ -556,7 +550,7 @@ func TestServeConfigETag(t *testing.T) {
t.Fatal("expected an error but got nil")
}
// a new config with no etag should succeed
// a new config with the empty-state etag should succeed
conf := &ipn.ServeConfig{
Web: map[ipn.HostPort]*ipn.WebServerConfig{
"example.ts.net:443": {Handlers: map[string]*ipn.HTTPHandler{
@@ -564,15 +558,14 @@ func TestServeConfigETag(t *testing.T) {
}},
},
}
err = b.SetServeConfig(conf, getEtag(t, nil))
err = b.SetServeConfig(conf, emptyStateETag)
if err != nil {
t.Fatal(err)
}
confView := b.ServeConfig()
etag := getEtag(t, confView)
if etag == "" {
t.Fatal("expected to get an etag but got an empty string")
confView, etag, err := b.ServeConfigETag()
if err != nil {
t.Fatal(err)
}
conf = confView.AsStruct()
mak.Set(&conf.AllowFunnel, "example.ts.net:443", true)
@@ -596,8 +589,10 @@ func TestServeConfigETag(t *testing.T) {
}
// replacing an existing config with the new etag should succeed
newCfg := b.ServeConfig()
etag = getEtag(t, newCfg)
_, etag, err = b.ServeConfigETag()
if err != nil {
t.Fatal(err)
}
err = b.SetServeConfig(nil, etag)
if err != nil {
t.Fatal(err)