मेरे गो कार्यक्रम को चलाने के दौरान, यह पैनिक करता है और निम्नलिखित लौटाता है:
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x38 pc=0x26df]
goroutine 1 [running]:
main.getBody(0x1cdcd4, 0xf800000004, 0x1f2b44, 0x23, 0xf84005c800, ...)
/Users/matt/Dropbox/code/go/scripts/cron/fido.go:65 +0x2bb
main.getToken(0xf84005c7e0, 0x10)
/Users/matt/Dropbox/code/go/scripts/cron/fido.go:140 +0x156
main.main()
/Users/matt/Dropbox/code/go/scripts/cron/fido.go:178 +0x61
goroutine 2 [syscall]:
created by runtime.main
/usr/local/Cellar/go/1.0.3/src/pkg/runtime/proc.c:221
goroutine 3 [syscall]:
syscall.Syscall6()
/usr/local/Cellar/go/1.0.3/src/pkg/syscall/asm_darwin_amd64.s:38 +0x5
syscall.kevent(0x6, 0x0, 0x0, 0xf840085188, 0xa, ...)
/usr/local/Cellar/go/1.0.3/src/pkg/syscall/zsyscall_darwin_amd64.go:199 +0x88
syscall.Kevent(0xf800000006, 0x0, 0x0, 0xf840085188, 0xa0000000a, ...)
/usr/local/Cellar/go/1.0.3/src/pkg/syscall/syscall_bsd.go:546 +0xa4
net.(*pollster).WaitFD(0xf840085180, 0xf840059040, 0x0, 0x0, 0x0, ...)
/usr/local/Cellar/go/1.0.3/src/pkg/net/fd_darwin.go:96 +0x185
net.(*pollServer).Run(0xf840059040, 0x0)
/usr/local/Cellar/go/1.0.3/src/pkg/net/fd.go:236 +0xe4
created by net.newPollServer
/usr/local/Cellar/go/1.0.3/src/pkg/net/newpollserver.go:35 +0x382मैंने उन प्रतिक्रियाओं को देखा है जो दूसरों को एक ही अपवाद के लिए मिली हैं, लेकिन कुछ भी सरल नहीं देखा जा सकता है (यानी एक अनहेल्ड त्रुटि)।
मैं इसे एक ऐसी मशीन पर चला रहा हूं जिसमें कोड में सूचीबद्ध एपीआई सर्वर तक पहुंच नहीं है, लेकिन मैं उम्मीद कर रहा था कि यह एक उपयुक्त त्रुटि लौटाएगा (जैसा कि मैंने उस तरह की त्रुटियों को पकड़ने का प्रयास किया है)।
package main
/*
Fido fetches the list of public images from the Glance server, captures the IDs of images with 'status': 'active' and then queues the images for pre-fetching with the Glance CLI utility `glance-cache-manage`. Once the images are added to the queue, `glance-cache-prefetcher` is called to actively fetch the queued images into the local compute nodes' image cache.
See http://docs.openstack.org/developer/glance/cache.html for further details on the Glance image cache.
*/
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
/*
"log"
"log/syslog"
*/
"net/http"
"os"
"os/exec"
)
func prefetchImages() error {
cmd := exec.Command("glance-cache-prefetcher")
err := cmd.Run()
if err != nil {
return fmt.Errorf("glance-cache-prefetcher failed to execute properly: %v", err)
}
return nil
}
func queueImages(hostname string, imageList []string) error {
for _, image := range imageList {
cmd := exec.Command("glance-cache-manage", "--host=", hostname, "queue-image", image)
err := cmd.Run()
if err != nil {
return fmt.Errorf("glance-cache-manage failed to execute properly: %v", err)
} else {
fmt.Printf("Image %s queued", image)
}
}
return nil
}
func getBody(method string, url string, headers map[string]string, body []byte) ([]byte, error) {
client := &http.Client{}
req, err := http.NewRequest(method, url, bytes.NewReader(body))
if err != nil {
return nil, err
}
for key, value := range headers {
req.Header.Add(key, value)
}
res, err := client.Do(req)
defer res.Body.Close()
if err != nil {
return nil, err
}
var bodyBytes []byte
if res.StatusCode == 200 {
bodyBytes, err = ioutil.ReadAll(res.Body)
} else if err != nil {
return nil, err
} else {
return nil, fmt.Errorf("The remote end did not return a HTTP 200 (OK) response.")
}
return bodyBytes, nil
}
func getImages(authToken string) ([]string, error) {
type GlanceDetailResponse struct {
Images []struct {
Name string `json:"name"`
Status string `json:"status"`
ID string `json:"id"`
}
}
method := "GET"
url := "http://192.168.1.2:9292/v1.1/images/detail"
headers := map[string]string{"X-Auth-Token": authToken}
bodyBytes, err := getBody(method, url, headers, nil)
if err != nil {
return nil, fmt.Errorf("unable to retrieve the response body from the Glance API server: %v", err)
}
var glance GlanceDetailResponse
err = json.Unmarshal(bodyBytes, &glance)
if err != nil {
return nil, fmt.Errorf("unable to parse the JSON response:", err)
}
imageList := make([]string, 10)
for _, image := range glance.Images {
if image.Status == "active" {
imageList = append(imageList, image.ID)
}
}
return imageList, nil
}
func getToken() (string, error) {
type TokenResponse struct {
Auth []struct {
Token struct {
Expires string `json:"expires"`
ID string `json:"id"`
}
}
}
method := "POST"
url := "http://192.168.1.2:5000/v2.0/tokens"
headers := map[string]string{"Content-type": "application/json"}
creds := []byte(`{"auth":{"passwordCredentials":{"username": "glance", "password":"<password>"}, "tenantId":"<tenantkeygoeshere>"}}`)
bodyBytes, err := getBody(method, url, headers, creds)
if err != nil {
return "", err
}
var keystone TokenResponse
err = json.Unmarshal(bodyBytes, &keystone)
if err != nil {
return "", err
}
authToken := string((keystone.Auth[0].Token.ID))
return authToken, nil
}
func main() {
/*
slog, err := syslog.New(syslog.LOG_ERR, "[fido]")
if err != nil {
log.Fatalf("unable to connect to syslog: %v", err)
os.Exit(1)
} else {
defer slog.Close()
}
*/
hostname, err := os.Hostname()
if err != nil {
// slog.Err("Hostname not captured")
os.Exit(1)
}
authToken, err := getToken()
if err != nil {
// slog.Err("The authentication token from the Glance API server was not retrieved")
os.Exit(1)
}
imageList, err := getImages(authToken)
err = queueImages(hostname, imageList)
if err != nil {
// slog.Err("Could not queue the images for pre-fetching")
os.Exit(1)
}
err = prefetchImages()
if err != nil {
// slog.Err("Could not queue the images for pre-fetching")
os.Exit(1)
}
return
}