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feat: add retry flag

cli
Karan Sharma 2022-07-02 11:19:47 +05:30
parent f7fe5a896c
commit f4d5f30b91
2 changed files with 23 additions and 5 deletions
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8
cmd/doggo/cli.go
View File

@ -39,7 +39,8 @@ func main() {
f.BoolP("reverse", "x", false, "Performs a DNS Lookup for an IPv4 or IPv6 address. Sets the query type and class to PTR and IN respectively.")
// Resolver Options
f.Int("timeout", 5, "Sets the timeout for a query to T seconds. The default timeout is 5 seconds.")
f.Int("timeout", 2, "Sets the timeout for a query to T seconds. The default timeout is 2 seconds.")
f.Int("retry", 3, "Number of times to retry DNS lookup")
f.Bool("search", true, "Use the search list provided in resolv.conf. It sets the `ndots` parameter as well unless overridden by `ndots` flag.")
f.Int("ndots", -1, "Specify the ndots parameter. Default value is taken from resolv.conf and fallbacks to 1 if ndots statement is missing in resolv.conf")
f.BoolP("ipv4", "4", false, "Use IPv4 only")
@ -75,7 +76,6 @@ func main() {
// Set log level.
if k.Bool("debug") {
// Set logger level
app.Logger.SetLevel(logf.DebugLevel)
}
// Unmarshall flags to the app.
@ -96,7 +96,6 @@ func main() {
// query type as PTR and query class as IN.
// Modify query name like 94.2.0.192.in-addr.arpa if it's an IPv4 address.
// Use IP6.ARPA nibble format otherwise.
if app.QueryFlags.ReverseLookup {
app.ReverseLookup()
}
@ -131,7 +130,6 @@ func main() {
}
app.Resolvers = rslvrs
// Run the app.
app.Logger.Debug("Starting doggo 🐶")
if len(app.QueryFlags.QNames) == 0 {
f.Usage()
@ -142,7 +140,7 @@ func main() {
var responses []resolvers.Response
for _, q := range app.Questions {
for _, rslv := range app.Resolvers {
resp, err := rslv.Lookup(q)
resp, err := app.LookupWithRetry(app.QueryFlags.RetryCount, rslv, q)
if err != nil {
app.Logger.WithError(err).Error("error looking up DNS records")
}

20
internal/app/app.go
View File

@ -1,6 +1,9 @@
package app
import (
"math/rand"
"time"
"github.com/miekg/dns"
"github.com/mr-karan/doggo/pkg/models"
"github.com/mr-karan/doggo/pkg/resolvers"
@ -33,3 +36,20 @@ func New(logger *logf.Logger, buildVersion string) App {
}
return app
}
// Attempts a DNS Lookup with retries for a given Question.
func (app *App) LookupWithRetry(attempts int, resolver resolvers.Resolver, ques dns.Question) (resolvers.Response, error) {
resp, err := resolver.Lookup(ques)
if err != nil {
// Retry lookup.
attempts--
if attempts > 0 {
// Add some random delay.
time.Sleep(time.Millisecond*300 + (time.Duration(rand.Int63n(int64(time.Millisecond*100))))/2)
app.Logger.Debug("retrying lookup")
return app.LookupWithRetry(attempts, resolver, ques)
}
return resolvers.Response{}, err
}
return resp, nil
}