distribution/health/health_test.go
Stephen J Day 6ba799b69e Provide simple storage driver health check
To ensure the ensure the web application is properly operating, we've added a
periodic health check for the storage driver. If the health check fails three
times in a row, the registry will serve 503 response status for any request
until the condition is resolved. The condition is reported in the response body
and via the /debug/health endpoint.

To ensure that all drivers will properly operate with this health check, a
function has been added to the driver testsuite.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2015-08-11 11:50:52 -07:00

107 lines
2.9 KiB
Go

package health
import (
"errors"
"fmt"
"net/http"
"net/http/httptest"
"testing"
)
// TestReturns200IfThereAreNoChecks ensures that the result code of the health
// endpoint is 200 if there are not currently registered checks.
func TestReturns200IfThereAreNoChecks(t *testing.T) {
recorder := httptest.NewRecorder()
req, err := http.NewRequest("GET", "https://fakeurl.com/debug/health", nil)
if err != nil {
t.Errorf("Failed to create request.")
}
StatusHandler(recorder, req)
if recorder.Code != 200 {
t.Errorf("Did not get a 200.")
}
}
// TestReturns500IfThereAreErrorChecks ensures that the result code of the
// health endpoint is 500 if there are health checks with errors
func TestReturns503IfThereAreErrorChecks(t *testing.T) {
recorder := httptest.NewRecorder()
req, err := http.NewRequest("GET", "https://fakeurl.com/debug/health", nil)
if err != nil {
t.Errorf("Failed to create request.")
}
// Create a manual error
Register("some_check", CheckFunc(func() error {
return errors.New("This Check did not succeed")
}))
StatusHandler(recorder, req)
if recorder.Code != 503 {
t.Errorf("Did not get a 503.")
}
}
// TestHealthHandler ensures that our handler implementation correct protects
// the web application when things aren't so healthy.
func TestHealthHandler(t *testing.T) {
// clear out existing checks.
registeredChecks = make(map[string]Checker)
// protect an http server
handler := http.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusNoContent)
}))
// wrap it in our health handler
handler = Handler(handler)
// use this swap check status
updater := NewStatusUpdater()
Register("test_check", updater)
// now, create a test server
server := httptest.NewServer(handler)
checkUp := func(t *testing.T, message string) {
resp, err := http.Get(server.URL)
if err != nil {
t.Fatalf("error getting success status: %v", err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusNoContent {
t.Fatalf("unexpected response code from server when %s: %d != %d", message, resp.StatusCode, http.StatusNoContent)
}
// NOTE(stevvooe): we really don't care about the body -- the format is
// not standardized or supported, yet.
}
checkDown := func(t *testing.T, message string) {
resp, err := http.Get(server.URL)
if err != nil {
t.Fatalf("error getting down status: %v", err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusServiceUnavailable {
t.Fatalf("unexpected response code from server when %s: %d != %d", message, resp.StatusCode, http.StatusServiceUnavailable)
}
}
// server should be up
checkUp(t, "initial health check")
// now, we fail the health check
updater.Update(fmt.Errorf("the server is now out of commission"))
checkDown(t, "server should be down") // should be down
// bring server back up
updater.Update(nil)
checkUp(t, "when server is back up") // now we should be back up.
}