/
main.go
460 lines (387 loc) · 12.3 KB
/
main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
package main
import (
"crypto/tls"
"crypto/x509"
"encoding/base64"
"log"
"net/http"
neturl "net/url"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"github.com/pkg/errors"
"github.com/spf13/pflag"
"github.com/spf13/viper"
"go.uber.org/zap"
"go.uber.org/zap/zapcore"
)
type stringSlice []string
func (s stringSlice) Contains(value string) bool {
for _, x := range s {
if value == x {
return true
}
}
return false
}
type intSlice []int
func (s intSlice) Contains(value int) bool {
for _, x := range s {
if value == x {
return true
}
}
return false
}
func stringSliceToIntSlice(strs []string) (intSlice, error) {
ints := intSlice(make([]int, 0, len(strs)))
for _, s := range strs {
i, err := strconv.Atoi(s)
if err != nil {
return ints, err
}
ints = append(ints, i)
}
return ints, nil
}
type errInvalidScheme struct {
Scheme string
}
func (e *errInvalidScheme) Error() string {
return "invalid scheme " + e.Scheme + ", only http and https are supported"
}
type errInvalidPath struct {
Path string
}
func (e *errInvalidPath) Error() string {
return "invalid path " + e.Path
}
type errInvalidStatusCode struct {
Code int
}
func (e *errInvalidStatusCode) Error() string {
return "invalid status code " + strconv.Itoa(e.Code)
}
type errHealthCheck struct {
URL string
StatusCode int
Tries int
}
func (e *errHealthCheck) Error() string {
return "request to url " + e.URL + " returned invalid status code " + strconv.Itoa(e.StatusCode) + " after " + strconv.Itoa(e.Tries) + " tries"
}
func checkConfig(v *viper.Viper) error {
schemesString := strings.TrimSpace(v.GetString("schemes"))
if len(schemesString) == 0 {
return errors.New("missing schemes")
}
schemes := stringSlice(strings.Split(schemesString, ","))
for _, scheme := range schemes {
if scheme != "http" && scheme != "https" {
return &errInvalidScheme{Scheme: scheme}
}
}
hosts := v.GetString("hosts")
if len(hosts) == 0 {
return errors.New("missing hosts")
}
pathsString := v.GetString("paths")
if len(pathsString) == 0 {
return errors.New("missing paths")
}
paths := stringSlice(strings.Split(pathsString, ","))
for _, path := range paths {
if !strings.HasPrefix(path, "/") {
return &errInvalidPath{Path: path}
}
}
statusCodesString := strings.TrimSpace(v.GetString("status-codes"))
if len(statusCodesString) == 0 {
return errors.New("missing status codes")
}
statusCodes, err := stringSliceToIntSlice(strings.Split(statusCodesString, ","))
if err != nil {
return errors.Wrap(err, "invalid status codes")
}
for _, statusCode := range statusCodes {
if len(http.StatusText(statusCode)) == 0 {
return &errInvalidStatusCode{Code: statusCode}
}
}
clientKeyEncoded := v.GetString("key")
clientCertEncoded := v.GetString("cert")
clientKeyFile := v.GetString("key-file")
clientCertFile := v.GetString("cert-file")
if len(clientKeyEncoded) > 0 || len(clientCertEncoded) > 0 || len(clientKeyFile) > 0 || len(clientCertFile) > 0 {
if schemes.Contains("http") {
return errors.New("cannot use scheme http with client certificate, can only use https")
}
}
tries := v.GetInt("tries")
if tries == 0 {
return errors.New("tries is 0, but must be greater than zero")
}
if tries > 1 {
backoff := v.GetInt("backoff")
if backoff == 0 {
return errors.New("backoff is 0, but must be greater than zero")
}
}
return nil
}
func createTLSConfig(clientKey []byte, clientCert []byte, ca []byte) (*tls.Config, error) {
keyPair, err := tls.X509KeyPair(clientCert, clientKey)
if err != nil {
return nil, err
}
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{keyPair},
MinVersion: tls.VersionTLS12,
MaxVersion: tls.VersionTLS13,
}
if len(ca) > 0 {
rootCAs := x509.NewCertPool()
rootCAs.AppendCertsFromPEM(ca)
tlsConfig.RootCAs = rootCAs
}
return tlsConfig, nil
}
func createHTTPClient(v *viper.Viper, logger *zap.Logger) (*http.Client, error) {
verbose := v.GetBool("verbose")
clientKeyEncoded := v.GetString("key")
clientCertEncoded := v.GetString("cert")
skipVerify := v.GetBool("skip-verify")
timeout := v.GetDuration("timeout")
if verbose {
if skipVerify {
logger.Info("Skipping client-side certificate validation")
}
}
// Supported TLS versions
tlsConfig := &tls.Config{
MinVersion: tls.VersionTLS12,
MaxVersion: tls.VersionTLS13,
}
if len(clientKeyEncoded) > 0 && len(clientCertEncoded) > 0 {
clientKey, clientKeyErr := base64.StdEncoding.DecodeString(clientKeyEncoded)
if clientKeyErr != nil {
return nil, errors.Wrap(clientKeyErr, "error decoding client key")
}
clientCert, clientCertErr := base64.StdEncoding.DecodeString(clientCertEncoded)
if clientCertErr != nil {
return nil, errors.Wrap(clientCertErr, "error decoding client cert")
}
caBytes := make([]byte, 0)
if caEncoded := v.GetString("ca"); len(caEncoded) > 0 {
caString, err := base64.StdEncoding.DecodeString(caEncoded)
if err != nil {
return nil, errors.Wrap(err, "error decoding certificate authority")
}
caBytes = []byte(caString)
}
var tlsConfigErr error
tlsConfig, tlsConfigErr = createTLSConfig([]byte(clientKey), []byte(clientCert), caBytes)
if tlsConfigErr != nil {
return nil, errors.Wrap(tlsConfigErr, "error creating TLS config")
}
} else {
clientKeyFile := v.GetString("key-file")
clientCertFile := v.GetString("cert-file")
if len(clientKeyFile) > 0 && len(clientCertFile) > 0 {
clientKey, clientKeyErr := os.ReadFile(filepath.Clean(clientKeyFile))
if clientKeyErr != nil {
return nil, errors.Wrap(clientKeyErr, "error reading client key file at "+clientKeyFile)
}
clientCert, clientCertErr := os.ReadFile(filepath.Clean(clientCertFile))
if clientCertErr != nil {
return nil, errors.Wrap(clientCertErr, "error reading client cert file at "+clientKeyFile)
}
caBytes := make([]byte, 0)
if caFile := v.GetString("ca-file"); len(caFile) > 0 {
content, err := os.ReadFile(filepath.Clean(caFile))
if err != nil {
return nil, errors.Wrap(err, "error reading ca file at "+caFile)
}
caBytes = content
}
var tlsConfigErr error
tlsConfig, tlsConfigErr = createTLSConfig(clientKey, clientCert, caBytes)
if tlsConfigErr != nil {
return nil, errors.Wrap(tlsConfigErr, "error creating TLS config")
}
}
}
httpTransport := &http.Transport{TLSClientConfig: tlsConfig}
httpClient := &http.Client{
Timeout: timeout,
Transport: httpTransport,
}
return httpClient, nil
}
func checkURL(httpClient *http.Client, url string, validStatusCodes intSlice, maxTries int, backoff int, logger *zap.Logger) error {
for tries := 0; tries < maxTries; tries++ {
statusCode := 0
resp, err := httpClient.Get(url)
if err != nil {
if uerr, ok := err.(*neturl.Error); ok && uerr.Timeout() {
logger.Info(
"HTTP GET request timed out",
zap.Int("try", tries),
zap.String("url", url))
} else {
return errors.Wrap(err, "error calling GET on url "+url)
}
} else {
statusCode = resp.StatusCode
logger.Info(
"HTTP GET request completed",
zap.Int("try", tries),
zap.String("url", url),
zap.Int("code", statusCode))
if validStatusCodes.Contains(statusCode) {
break
}
}
if tries < maxTries-1 {
sleepPeriod := time.Duration((tries+1)*backoff) * time.Second
logger.Info("sleeping", zap.Duration("period", sleepPeriod))
time.Sleep(sleepPeriod)
continue
}
return &errHealthCheck{URL: url, StatusCode: statusCode, Tries: maxTries}
}
return nil
}
func createLogger(env string, level string) (*zap.Logger, func(), error) {
// No sync of the logger is necessary when logging to stderr as is
// the default. This logging package does not provide an option to
// override the logging destination, so this is always correct
//
// If an option is added in the future, this will need to be updated
noopLoggerSync := func() {}
loglevel := zapcore.Level(uint8(0))
err := (&loglevel).UnmarshalText([]byte(level))
if err != nil {
return nil, noopLoggerSync, err
}
atomicLevel := zap.NewAtomicLevel()
atomicLevel.SetLevel(loglevel)
var loggerConfig zap.Config
if env == "production" || env == "prod" {
loggerConfig = zap.NewProductionConfig()
} else {
loggerConfig = zap.NewDevelopmentConfig()
}
loggerConfig.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
loggerConfig.Level = atomicLevel
loggerConfig.DisableStacktrace = true
logger, err := loggerConfig.Build(zap.AddStacktrace(zap.ErrorLevel))
return logger, noopLoggerSync, err
}
func main() {
flag := pflag.CommandLine
flag.StringP("schemes", "s", "http,https", "slice of schemes to check")
flag.String("hosts", "", "comma-separated list of host names to check")
flag.StringP("paths", "p", "/health", "slice of paths to check on each host")
flag.String("key", "", "path to file of base64-encoded private key for client TLS")
flag.String("key-file", "", "path to file of base64-encoded private key for client TLS")
flag.String("cert", "", "base64-encoded public key for client TLS")
flag.String("cert-file", "", "path to file of base64-encoded public key for client TLS")
flag.String("ca", "", "base64-encoded certificate authority for mutual TLS")
flag.String("ca-file", "", "path to file of base64-encoded certificate authority for mutual TLS")
flag.String("status-codes", "200", "valid response status codes")
flag.Bool("skip-verify", false, "skip certifiate validation")
flag.Int("tries", 5, "number of tries")
flag.Int("backoff", 1, "backoff in seconds")
flag.Duration("timeout", 5*time.Minute, "timeout duration")
flag.Bool("exit-on-error", false, "exit on first health check error")
flag.String("log-env", "development", "logging config: development or production")
flag.String("log-level", "error", "log level: debug, info, warn, error, dpanic, panic, or fatal")
flag.Bool("verbose", false, "output extra information")
parseErr := flag.Parse(os.Args[1:])
if parseErr != nil {
log.Fatalf("Could not parse flags: %v\n", parseErr)
}
v := viper.New()
bindErr := v.BindPFlags(flag)
if bindErr != nil {
log.Fatal("failed to bind flags", zap.Error(bindErr))
}
v.SetEnvPrefix("HEALTHCHECKER")
v.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
v.AutomaticEnv()
healthCheckErrors := make([]error, 0)
defer func() {
if len(healthCheckErrors) > 0 {
os.Exit(1)
}
}()
logger, loggerSync, err := createLogger(v.GetString("log-env"), v.GetString("log-level"))
if err != nil {
log.Fatal(err.Error())
}
defer loggerSync()
err = checkConfig(v)
if err != nil {
switch e := err.(type) {
case *errInvalidPath:
logger.Fatal(e.Error(), zap.String("path", e.Path))
case *errInvalidScheme:
logger.Fatal(e.Error(), zap.String("scheme", e.Scheme))
case *errInvalidStatusCode:
logger.Fatal(e.Error(), zap.Int("code", e.Code))
}
logger.Fatal(err.Error())
}
verbose := v.GetBool("verbose")
schemes := strings.Split(strings.TrimSpace(v.GetString("schemes")), ",")
hosts := strings.Split(strings.TrimSpace(v.GetString("hosts")), ",")
paths := strings.Split(strings.TrimSpace(v.GetString("paths")), ",")
statusCodes, _ := stringSliceToIntSlice(strings.Split(strings.TrimSpace(v.GetString("status-codes")), ","))
httpClient, err := createHTTPClient(v, logger)
if err != nil {
logger.Fatal(errors.Wrap(err, "error creating http client").Error())
}
maxTries := v.GetInt("tries")
backoff := v.GetInt("backoff")
exitOnError := v.GetBool("exit-on-error")
for _, scheme := range schemes {
for _, host := range hosts {
for _, path := range paths {
url := scheme + "://" + host + path
if verbose {
logger.Info("checking url will connect", zap.String("url", url))
}
err := checkURL(httpClient, url, statusCodes, maxTries, backoff, logger)
if err != nil {
if exitOnError {
switch e := err.(type) {
case *errHealthCheck:
logger.Fatal(
"health check failed",
zap.String("url", e.URL),
zap.Int("statusCode", e.StatusCode),
zap.Int("tries", e.Tries))
default:
logger.Fatal(err.Error())
}
} else {
switch e := err.(type) {
case *errHealthCheck:
logger.Warn(
"health check failed",
zap.String("url", e.URL),
zap.Int("statusCode", e.StatusCode),
zap.Int("tries", e.Tries))
default:
logger.Warn(err.Error())
}
healthCheckErrors = append(healthCheckErrors, err)
}
}
}
}
}
}