tailscale/doctor/doctor.go

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// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package doctor contains more in-depth healthchecks that can be run to aid in
// diagnosing Tailscale issues.
package doctor
import (
"context"
"sync"
"tailscale.com/types/logger"
)
// Check is the interface defining a singular check.
//
// A check should log information that it gathers using the provided log
// function, and should attempt to make as much progress as possible in error
// conditions.
type Check interface {
// Name should return a name describing this check, in lower-kebab-case
// (i.e. "my-check", not "MyCheck" or "my_check").
Name() string
// Run executes the check, logging diagnostic information to the
// provided logger function.
Run(context.Context, logger.Logf) error
}
// RunChecks runs a list of checks in parallel, and logs any returned errors
// after all checks have returned.
func RunChecks(ctx context.Context, log logger.Logf, checks ...Check) {
if len(checks) == 0 {
return
}
type namedErr struct {
name string
err error
}
errs := make(chan namedErr, len(checks))
var wg sync.WaitGroup
wg.Add(len(checks))
for _, check := range checks {
go func(c Check) {
defer wg.Done()
plog := logger.WithPrefix(log, c.Name()+": ")
errs <- namedErr{
name: c.Name(),
err: c.Run(ctx, plog),
}
}(check)
}
wg.Wait()
close(errs)
for n := range errs {
if n.err == nil {
continue
}
log("check %s: %v", n.name, n.err)
}
}
// CheckFunc creates a Check from a name and a function.
func CheckFunc(name string, run func(context.Context, logger.Logf) error) Check {
return checkFunc{name, run}
}
type checkFunc struct {
name string
run func(context.Context, logger.Logf) error
}
func (c checkFunc) Name() string { return c.name }
func (c checkFunc) Run(ctx context.Context, log logger.Logf) error { return c.run(ctx, log) }