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HttpClient: Refactor timeout into two seperate functions

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This commit is contained in:
Alex Crawford 2014-06-26 14:58:32 -07:00
parent ad66b1c92f
commit 68dc902ed1
7 changed files with 77 additions and 58 deletions
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10
datasource/metadata_service.go
View File

@ -32,7 +32,7 @@ const (
type metadataService struct{}
type getter interface {
Get(string) ([]byte, error)
GetRetry(string) ([]byte, error)
}
func NewMetadataService() *metadataService {
@ -49,12 +49,12 @@ func (ms *metadataService) FetchMetadata() ([]byte, error) {
func (ms *metadataService) FetchUserdata() ([]byte, error) {
client := pkg.NewHttpClient()
if data, err := client.Get(Ec2UserdataUrl); err == nil {
if data, err := client.GetRetry(Ec2UserdataUrl); err == nil {
return data, err
} else if _, ok := err.(pkg.ErrTimeout); ok {
return data, err
}
return client.Get(OpenstackUserdataUrl)
return client.GetRetry(OpenstackUserdataUrl)
}
func (ms *metadataService) Type() string {
@ -62,7 +62,7 @@ func (ms *metadataService) Type() string {
}
func fetchMetadata(client getter) ([]byte, error) {
if metadata, err := client.Get(OpenstackMetadataUrl); err == nil {
if metadata, err := client.GetRetry(OpenstackMetadataUrl); err == nil {
return metadata, nil
} else if _, ok := err.(pkg.ErrTimeout); ok {
return nil, err
@ -76,7 +76,7 @@ func fetchMetadata(client getter) ([]byte, error) {
}
func fetchAttributes(client getter, url string) ([]string, error) {
resp, err := client.Get(url)
resp, err := client.GetRetry(url)
if err != nil {
return nil, err
}

2
datasource/metadata_service_test.go
View File

@ -14,7 +14,7 @@ type TestHttpClient struct {
err error
}
func (t *TestHttpClient) Get(url string) ([]byte, error) {
func (t *TestHttpClient) GetRetry(url string) ([]byte, error) {
if t.err != nil {
return nil, t.err
}

2
datasource/proc_cmdline.go
View File

@ -43,7 +43,7 @@ func (c *procCmdline) FetchUserdata() ([]byte, error) {
}
client := pkg.NewHttpClient()
cfg, err := client.Get(url)
cfg, err := client.GetRetry(url)
if err != nil {
return nil, err
}

2
datasource/url.go
View File

@ -20,7 +20,7 @@ func (f *remoteFile) FetchMetadata() ([]byte, error) {
func (f *remoteFile) FetchUserdata() ([]byte, error) {
client := pkg.NewHttpClient()
return client.Get(f.url)
return client.GetRetry(f.url)
}
func (f *remoteFile) Type() string {

2
initialize/ssh_keys.go
View File

@ -25,7 +25,7 @@ func SSHImportKeysFromURL(system_user string, url string) error {
func fetchUserKeys(url string) ([]string, error) {
client := pkg.NewHttpClient()
data, err := client.Get(url)
data, err := client.GetRetry(url)
if err != nil {
return nil, err
}

103
pkg/http_client.go
View File

@ -32,6 +32,14 @@ type ErrInvalid struct{
Err
}
type ErrServer struct {
Err
}
type ErrNetwork struct {
Err
}
type HttpClient struct {
// Maximum exp backoff duration. Defaults to 5 seconds
MaxBackoff time.Duration
@ -45,15 +53,39 @@ type HttpClient struct {
// Whether or not to skip TLS verification. Defaults to false
SkipTLS bool
client *http.Client
}
func NewHttpClient() *HttpClient {
return &HttpClient{
hc := &HttpClient{
MaxBackoff: time.Second * 5,
MaxRetries: 15,
Timeout: time.Duration(2) * time.Second,
SkipTLS: false,
}
// We need to create our own client in order to add timeout support.
// TODO(c4milo) Replace it once Go 1.3 is officially used by CoreOS
// More info: https://code.google.com/p/go/source/detail?r=ada6f2d5f99f
hc.client = &http.Client{
Transport: &http.Transport{
TLSClientConfig: &tls.Config{
InsecureSkipVerify: hc.SkipTLS,
},
Dial: func(network, addr string) (net.Conn, error) {
deadline := time.Now().Add(hc.Timeout)
c, err := net.DialTimeout(network, addr, hc.Timeout)
if err != nil {
return nil, err
}
c.SetDeadline(deadline)
return c, nil
},
},
}
return hc
}
func expBackoff(interval, max time.Duration) time.Duration {
@ -64,8 +96,8 @@ func expBackoff(interval, max time.Duration) time.Duration {
return interval
}
// Fetches a given URL with support for exponential backoff and maximum retries
func (h *HttpClient) Get(rawurl string) ([]byte, error) {
// GetRetry fetches a given URL with support for exponential backoff and maximum retries
func (h *HttpClient) GetRetry(rawurl string) ([]byte, error) {
if rawurl == "" {
return nil, ErrInvalid{errors.New("URL is empty. Skipping.")}
}
@ -83,49 +115,20 @@ func (h *HttpClient) Get(rawurl string) ([]byte, error) {
dataURL := url.String()
// We need to create our own client in order to add timeout support.
// TODO(c4milo) Replace it once Go 1.3 is officially used by CoreOS
// More info: https://code.google.com/p/go/source/detail?r=ada6f2d5f99f
transport := &http.Transport{
TLSClientConfig: &tls.Config{
InsecureSkipVerify: h.SkipTLS,
},
Dial: func(network, addr string) (net.Conn, error) {
deadline := time.Now().Add(h.Timeout)
c, err := net.DialTimeout(network, addr, h.Timeout)
if err != nil {
return nil, err
}
c.SetDeadline(deadline)
return c, nil
},
}
client := &http.Client{
Transport: transport,
}
duration := 50 * time.Millisecond
for retry := 1; retry <= h.MaxRetries; retry++ {
log.Printf("Fetching data from %s. Attempt #%d", dataURL, retry)
resp, err := client.Get(dataURL)
if err == nil {
defer resp.Body.Close()
status := resp.StatusCode / 100
if status == HTTP_2xx {
return ioutil.ReadAll(resp.Body)
}
if status == HTTP_4xx {
return nil, ErrNotFound{fmt.Errorf("Not found. HTTP status code: %d", resp.StatusCode)}
}
log.Printf("Server error. HTTP status code: %d", resp.StatusCode)
} else {
log.Printf("Unable to fetch data: %s", err.Error())
data, err := h.Get(dataURL)
switch err.(type) {
case ErrNetwork:
log.Printf(err.Error())
case ErrServer:
log.Printf(err.Error())
case ErrNotFound:
return data, err
default:
return data, err
}
duration = expBackoff(duration, h.MaxBackoff)
@ -135,3 +138,19 @@ func (h *HttpClient) Get(rawurl string) ([]byte, error) {
return nil, ErrTimeout{fmt.Errorf("Unable to fetch data. Maximum retries reached: %d", h.MaxRetries)}
}
func (h *HttpClient) Get(dataURL string) ([]byte, error) {
if resp, err := h.client.Get(dataURL); err == nil {
defer resp.Body.Close()
switch resp.StatusCode / 100 {
case HTTP_2xx:
return ioutil.ReadAll(resp.Body)
case HTTP_4xx:
return nil, ErrNotFound{fmt.Errorf("Not found. HTTP status code: %d", resp.StatusCode)}
default:
return nil, ErrServer{fmt.Errorf("Server error. HTTP status code: %d", resp.StatusCode)}
}
} else {
return nil, ErrNetwork{fmt.Errorf("Unable to fetch data: %s", err.Error())}
}
}

8
pkg/http_client_test.go
View File

@ -51,7 +51,7 @@ func TestGetURLExpBackOff(t *testing.T) {
ts := httptest.NewServer(mux)
defer ts.Close()
data, err := client.Get(ts.URL)
data, err := client.GetRetry(ts.URL)
if err != nil {
t.Errorf("Test case %d produced error: %v", i, err)
}
@ -76,7 +76,7 @@ func TestGetURL4xx(t *testing.T) {
}))
defer ts.Close()
_, err := client.Get(ts.URL)
_, err := client.GetRetry(ts.URL)
if err == nil {
t.Errorf("Incorrect result\ngot: %s\nwant: %s", err.Error(), "Not found. HTTP status code: 404")
}
@ -107,7 +107,7 @@ coreos:
}))
defer ts.Close()
data, err := client.Get(ts.URL)
data, err := client.GetRetry(ts.URL)
if err != nil {
t.Errorf("Incorrect result\ngot: %v\nwant: %v", err, nil)
}
@ -132,7 +132,7 @@ func TestGetMalformedURL(t *testing.T) {
}
for _, test := range tests {
_, err := client.Get(test.url)
_, err := client.GetRetry(test.url)
if err == nil || err.Error() != test.want {
t.Errorf("Incorrect result\ngot: %v\nwant: %v", err, test.want)
}