cff5e693d2
- Order of threads to shutdown (control then tickers then health etc.) - Rely on closing channels instead of waitgroups - Move exit logs from each package to the shutdown package
75 lines
1.5 KiB
Go
75 lines
1.5 KiB
Go
// Package healthcheck defines the client and server side of the built in healthcheck.
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package healthcheck
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import (
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"context"
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"errors"
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"fmt"
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"net"
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"time"
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)
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func (s *server) runHealthcheckLoop(ctx context.Context, healthy chan<- bool, done chan<- struct{}) {
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defer close(done)
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for {
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previousErr := s.handler.getErr()
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err := healthCheck(ctx, s.resolver)
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s.handler.setErr(err)
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// Notify the healthy channel, or not if it's already full
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select {
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case healthy <- err == nil:
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default:
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}
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if previousErr != nil && err == nil {
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s.logger.Info("healthy!")
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} else if previousErr == nil && err != nil {
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s.logger.Info("unhealthy: " + err.Error())
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}
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if err != nil { // try again after 1 second
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timer := time.NewTimer(time.Second)
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select {
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case <-ctx.Done():
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if !timer.Stop() {
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<-timer.C
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}
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return
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case <-timer.C:
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}
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continue
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}
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// Success, check again in 5 seconds
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const period = 5 * time.Second
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timer := time.NewTimer(period)
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select {
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case <-ctx.Done():
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if !timer.Stop() {
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<-timer.C
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}
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return
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case <-timer.C:
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}
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}
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}
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var (
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errNoIPResolved = errors.New("no IP address resolved")
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)
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func healthCheck(ctx context.Context, resolver *net.Resolver) (err error) {
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// TODO use mullvad API if current provider is Mullvad
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const domainToResolve = "github.com"
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ips, err := resolver.LookupIP(ctx, "ip", domainToResolve)
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switch {
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case err != nil:
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return err
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case len(ips) == 0:
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return fmt.Errorf("%w for %s", errNoIPResolved, domainToResolve)
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default:
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return nil
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}
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}
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