137 lines
3.8 KiB
Go
137 lines
3.8 KiB
Go
package watchdog
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import (
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"context"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/url"
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"time"
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)
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// DefaultTimeout is used to limit checks duration
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const DefaultTimeout = time.Second * 10
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// GetHTTP creates a CheckFunc that operates as follows.
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// The check calls GET method for provided addr using http.DefaultClient.
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// If request fails within specified timeout the returned status is StatusDown.
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// The function then tries to read response body. If it fails,
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// the returned status is StatusDown.
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// If request secceeds but reponse code is not 200, the returned
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// status is StatusPartiallyAvailable and response body is contained in the
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// returned error.
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//
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// GetHTTP return an error if addr can not be parsed with url.Parse.
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// If zero timeout is provided then the DefaultTimeout (10 second) is used.
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func GetHTTP(addr string, timeout time.Duration) (CheckFunc, error) {
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u, err := url.Parse(addr)
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if err != nil {
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return nil, fmt.Errorf("coulf not parse URL: %w", err)
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}
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if timeout == 0 {
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timeout = DefaultTimeout
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}
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return func(ctx context.Context) (Status, error) {
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ctx, cancel := context.WithTimeout(ctx, timeout)
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defer cancel()
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
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if err != nil {
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return StatusUnknown, fmt.Errorf("failed to create http request: %w", err)
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return StatusDown, fmt.Errorf("do request failed: %w", err)
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}
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defer resp.Body.Close()
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return StatusDown, fmt.Errorf("err reading response body: %w", err)
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}
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if resp.StatusCode != http.StatusOK {
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return StatusDown, fmt.Errorf("got HTTP response code %d, body: %s", resp.StatusCode, string(body))
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}
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return StatusOK, nil
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}, nil
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}
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// HeadHTTP creates a CheckFunc that operates as follows.
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// The check calls GET method for provided addr using http.DefaultClient.
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// If request fails within specified timeout the returned status is StatusDown.
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//
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// If request secceeds but reponse code is not 200, the returned
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// status is StatusPartiallyAvailable.
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//
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// HeadHTTP return an error if addr can not be parsed with url.Parse.
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// If zero timeout is provided then the DefaultTimeout (10 second) is used.
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func HeadHTTP(addr string, timeout time.Duration) (CheckFunc, error) {
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u, err := url.Parse(addr)
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if err != nil {
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return nil, fmt.Errorf("coulf not parse URL: %w", err)
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}
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if timeout == 0 {
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timeout = DefaultTimeout
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}
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return func(ctx context.Context) (Status, error) {
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ctx, cancel := context.WithTimeout(ctx, timeout)
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defer cancel()
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req, err := http.NewRequestWithContext(ctx, http.MethodHead, u.String(), nil)
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if err != nil {
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return StatusUnknown, fmt.Errorf("failed to create http request: %w", err)
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return StatusDown, fmt.Errorf("do request failed: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return StatusDown, fmt.Errorf("got HTTP response code %d", resp.StatusCode)
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}
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return http.StatusOK, nil
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}, nil
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}
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// DialTCP creates a CheckFunc that may be used to check tcp connectivity
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// to a host.
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// The check tries to net.DialTimeout to the provided addr. If it fails,
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// the returned status is StatusDown.
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//
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// No validation of addr is made.
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// If zero timeout is provided then the DefaultTimeout (10 second) is used.
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func DialTCP(addr string, timeout time.Duration) (CheckFunc, error) {
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if timeout == 0 {
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timeout = DefaultTimeout
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}
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return func(ctx context.Context) (Status, error) {
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deadline := time.Now().Add(timeout)
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if t, ok := ctx.Deadline(); ok && t.Before(deadline) {
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deadline = t
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}
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conn, err := net.DialTimeout("tcp", addr, time.Until(deadline))
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if err != nil {
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return StatusDown, fmt.Errorf("error dialing: %w", err)
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}
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defer conn.Close()
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return StatusOK, nil
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}, nil
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}
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