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tailscale/cmd/gitops-pusher/gitops-pusher.go

374 lines
9.0 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Command gitops-pusher allows users to use a GitOps flow for managing Tailscale ACLs.
//
// See README.md for more details.
package main
import (
"context"
"crypto/sha256"
"encoding/json"
"flag"
"fmt"
"log"
"net/http"
"os"
"regexp"
"strings"
"time"
"github.com/peterbourgon/ff/v3/ffcli"
"github.com/tailscale/hujson"
)
var (
rootFlagSet = flag.NewFlagSet("gitops-pusher", flag.ExitOnError)
policyFname = rootFlagSet.String("policy-file", "./policy.hujson", "filename for policy file")
cacheFname = rootFlagSet.String("cache-file", "./version-cache.json", "filename for the previous known version hash")
timeout = rootFlagSet.Duration("timeout", 5*time.Minute, "timeout for the entire CI run")
githubSyntax = rootFlagSet.Bool("github-syntax", true, "use GitHub Action error syntax (https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-error-message)")
modifiedExternallyFailure = make(chan struct{}, 1)
)
func modifiedExternallyError() {
if *githubSyntax {
fmt.Printf("::error file=%s,line=1,col=1,title=Policy File Modified Externally::The policy file was modified externally in the admin console.\n", *policyFname)
} else {
fmt.Printf("The policy file was modified externally in the admin console.\n")
}
modifiedExternallyFailure <- struct{}{}
}
func apply(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
return func(ctx context.Context, args []string) error {
controlEtag, err := getACLETag(ctx, tailnet, apiKey)
if err != nil {
return err
}
localEtag, err := sumFile(*policyFname)
if err != nil {
return err
}
if cache.PrevETag == "" {
log.Println("no previous etag found, assuming local file is correct and recording that")
cache.PrevETag = localEtag
}
log.Printf("control: %s", controlEtag)
log.Printf("local: %s", localEtag)
log.Printf("cache: %s", cache.PrevETag)
if cache.PrevETag != controlEtag {
modifiedExternallyError()
}
if controlEtag == localEtag {
cache.PrevETag = localEtag
log.Println("no update needed, doing nothing")
return nil
}
if err := applyNewACL(ctx, tailnet, apiKey, *policyFname, controlEtag); err != nil {
return err
}
cache.PrevETag = localEtag
return nil
}
}
func test(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
return func(ctx context.Context, args []string) error {
controlEtag, err := getACLETag(ctx, tailnet, apiKey)
if err != nil {
return err
}
localEtag, err := sumFile(*policyFname)
if err != nil {
return err
}
if cache.PrevETag == "" {
log.Println("no previous etag found, assuming local file is correct and recording that")
cache.PrevETag = localEtag
}
log.Printf("control: %s", controlEtag)
log.Printf("local: %s", localEtag)
log.Printf("cache: %s", cache.PrevETag)
if cache.PrevETag != controlEtag {
modifiedExternallyError()
}
if controlEtag == localEtag {
log.Println("no updates found, doing nothing")
return nil
}
if err := testNewACLs(ctx, tailnet, apiKey, *policyFname); err != nil {
return err
}
return nil
}
}
func getChecksums(cache *Cache, tailnet, apiKey string) func(context.Context, []string) error {
return func(ctx context.Context, args []string) error {
controlEtag, err := getACLETag(ctx, tailnet, apiKey)
if err != nil {
return err
}
localEtag, err := sumFile(*policyFname)
if err != nil {
return err
}
if cache.PrevETag == "" {
log.Println("no previous etag found, assuming local file is correct and recording that")
cache.PrevETag = Shuck(localEtag)
}
log.Printf("control: %s", controlEtag)
log.Printf("local: %s", localEtag)
log.Printf("cache: %s", cache.PrevETag)
return nil
}
}
func main() {
tailnet, ok := os.LookupEnv("TS_TAILNET")
if !ok {
log.Fatal("set envvar TS_TAILNET to your tailnet's name")
}
apiKey, ok := os.LookupEnv("TS_API_KEY")
if !ok {
log.Fatal("set envvar TS_API_KEY to your Tailscale API key")
}
cache, err := LoadCache(*cacheFname)
if err != nil {
if os.IsNotExist(err) {
cache = &Cache{}
} else {
log.Fatalf("error loading cache: %v", err)
}
}
defer cache.Save(*cacheFname)
applyCmd := &ffcli.Command{
Name: "apply",
ShortUsage: "gitops-pusher [options] apply",
ShortHelp: "Pushes changes to CONTROL",
LongHelp: `Pushes changes to CONTROL`,
Exec: apply(cache, tailnet, apiKey),
}
testCmd := &ffcli.Command{
Name: "test",
ShortUsage: "gitops-pusher [options] test",
ShortHelp: "Tests ACL changes",
LongHelp: "Tests ACL changes",
Exec: test(cache, tailnet, apiKey),
}
cksumCmd := &ffcli.Command{
Name: "checksum",
ShortUsage: "Shows checksums of ACL files",
ShortHelp: "Fetch checksum of CONTROL's ACL and the local ACL for comparison",
LongHelp: "Fetch checksum of CONTROL's ACL and the local ACL for comparison",
Exec: getChecksums(cache, tailnet, apiKey),
}
root := &ffcli.Command{
ShortUsage: "gitops-pusher [options] <command>",
ShortHelp: "Push Tailscale ACLs to CONTROL using a GitOps workflow",
Subcommands: []*ffcli.Command{applyCmd, cksumCmd, testCmd},
FlagSet: rootFlagSet,
}
if err := root.Parse(os.Args[1:]); err != nil {
log.Fatal(err)
}
ctx, cancel := context.WithTimeout(context.Background(), *timeout)
defer cancel()
if err := root.Run(ctx); err != nil {
fmt.Println(err)
os.Exit(1)
}
if len(modifiedExternallyFailure) != 0 {
os.Exit(1)
}
}
func sumFile(fname string) (string, error) {
data, err := os.ReadFile(fname)
if err != nil {
return "", err
}
formatted, err := hujson.Format(data)
if err != nil {
return "", err
}
h := sha256.New()
_, err = h.Write(formatted)
if err != nil {
return "", err
}
return fmt.Sprintf("%x", h.Sum(nil)), nil
}
func applyNewACL(ctx context.Context, tailnet, apiKey, policyFname, oldEtag string) error {
fin, err := os.Open(policyFname)
if err != nil {
return err
}
defer fin.Close()
req, err := http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl", tailnet), fin)
if err != nil {
return err
}
req.SetBasicAuth(apiKey, "")
req.Header.Set("Content-Type", "application/hujson")
req.Header.Set("If-Match", `"`+oldEtag+`"`)
resp, err := http.DefaultClient.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
got := resp.StatusCode
want := http.StatusOK
if got != want {
var ate ACLTestError
err := json.NewDecoder(resp.Body).Decode(&ate)
if err != nil {
return err
}
return ate
}
return nil
}
func testNewACLs(ctx context.Context, tailnet, apiKey, policyFname string) error {
fin, err := os.Open(policyFname)
if err != nil {
return err
}
defer fin.Close()
req, err := http.NewRequestWithContext(ctx, http.MethodPost, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl/validate", tailnet), fin)
if err != nil {
return err
}
req.SetBasicAuth(apiKey, "")
req.Header.Set("Content-Type", "application/hujson")
resp, err := http.DefaultClient.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
var ate ACLTestError
err = json.NewDecoder(resp.Body).Decode(&ate)
if err != nil {
return err
}
if len(ate.Message) != 0 || len(ate.Data) != 0 {
return ate
}
got := resp.StatusCode
want := http.StatusOK
if got != want {
return fmt.Errorf("wanted HTTP status code %d but got %d", want, got)
}
return nil
}
var lineColMessageSplit = regexp.MustCompile(`line ([0-9]+), column ([0-9]+): (.*)$`)
type ACLTestError struct {
Message string `json:"message"`
Data []ACLTestErrorDetail `json:"data"`
}
func (ate ACLTestError) Error() string {
var sb strings.Builder
if *githubSyntax && lineColMessageSplit.MatchString(ate.Message) {
sp := lineColMessageSplit.FindStringSubmatch(ate.Message)
line := sp[1]
col := sp[2]
msg := sp[3]
fmt.Fprintf(&sb, "::error file=%s,line=%s,col=%s::%s", *policyFname, line, col, msg)
} else {
fmt.Fprintln(&sb, ate.Message)
}
fmt.Fprintln(&sb)
for _, data := range ate.Data {
fmt.Fprintf(&sb, "For user %s:\n", data.User)
for _, err := range data.Errors {
fmt.Fprintf(&sb, "- %s\n", err)
}
}
return sb.String()
}
type ACLTestErrorDetail struct {
User string `json:"user"`
Errors []string `json:"errors"`
}
func getACLETag(ctx context.Context, tailnet, apiKey string) (string, error) {
req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("https://api.tailscale.com/api/v2/tailnet/%s/acl", tailnet), nil)
if err != nil {
return "", err
}
req.SetBasicAuth(apiKey, "")
req.Header.Set("Accept", "application/hujson")
resp, err := http.DefaultClient.Do(req)
if err != nil {
return "", err
}
defer resp.Body.Close()
got := resp.StatusCode
want := http.StatusOK
if got != want {
return "", fmt.Errorf("wanted HTTP status code %d but got %d", want, got)
}
return Shuck(resp.Header.Get("ETag")), nil
}