130 lines
3.8 KiB
Go
130 lines
3.8 KiB
Go
// Copyright 2020 by the contributors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package healthcheck
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import (
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"context"
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"database/sql"
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"fmt"
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"net"
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"net/http"
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"runtime"
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"time"
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)
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// TCPDialCheck returns a Check that checks TCP connectivity to the provided
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// endpoint.
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func TCPDialCheck(addr string, timeout time.Duration) Check {
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return func() error {
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conn, err := net.DialTimeout("tcp", addr, timeout)
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if err != nil {
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return err
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}
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return conn.Close()
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}
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}
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// HTTPGetCheck returns a Check that performs an HTTP GET request against the
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// specified URL. The check fails if the response times out or returns a non-200
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// status code.
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func HTTPGetCheck(url string, timeout time.Duration) Check {
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return func() error {
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return HTTPCheck(url, http.MethodGet, http.StatusOK, timeout)()
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}
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}
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// HTTPCheck returns a Check that performs a HTTP request against the specified URL.
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// The Check fails if the response times out or returns an unexpected status code.
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func HTTPCheck(url string, method string, status int, timeout time.Duration) Check {
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client := &http.Client{
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Timeout: timeout,
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CheckRedirect: func(*http.Request, []*http.Request) error {
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return http.ErrUseLastResponse
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},
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}
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return HTTPCheckClient(client, url, method, status, timeout)
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}
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// HTTPCheckClient returns a Check that performs a HTTP request against the specified URL.
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// The Check fails if the response times out or returns an unexpected status code.
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// On top of that it uses a custom client specified by the caller.
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func HTTPCheckClient(client *http.Client, url string, method string, status int, timeout time.Duration) Check {
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return func() error {
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ctx, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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req, err := http.NewRequest(method, url, nil)
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if err != nil {
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return err
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}
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req = req.WithContext(ctx)
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resp, err := client.Do(req)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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if resp.StatusCode != status {
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return fmt.Errorf("returned status %d, expected %d", resp.StatusCode, status)
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}
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return nil
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}
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}
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// DatabasePingCheck returns a Check that validates connectivity to a
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// database/sql.DB using Ping().
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func DatabasePingCheck(database *sql.DB, timeout time.Duration) Check {
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return func() error {
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ctx, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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if database == nil {
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return fmt.Errorf("database is nil")
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}
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return database.PingContext(ctx)
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}
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}
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// DNSResolveCheck returns a Check that makes sure the provided host can resolve
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// to at least one IP address within the specified timeout.
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func DNSResolveCheck(host string, timeout time.Duration) Check {
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resolver := net.Resolver{}
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return func() error {
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ctx, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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addrs, err := resolver.LookupHost(ctx, host)
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if err != nil {
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return err
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}
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if len(addrs) < 1 {
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return fmt.Errorf("could not resolve host")
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}
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return nil
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}
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}
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// GoroutineCountCheck returns a Check that fails if too many goroutines are
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// running (which could indicate a resource leak).
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func GoroutineCountCheck(threshold int) Check {
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return func() error {
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count := runtime.NumGoroutine()
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if count > threshold {
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return fmt.Errorf("too many goroutines (%d > %d)", count, threshold)
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}
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return nil
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}
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}
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