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GODRIVER-2620 Fix hostname parsing for SRV polling. #1112

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merged 6 commits into from Oct 28, 2022
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14 changes: 13 additions & 1 deletion x/mongo/driver/topology/polling_srv_records_test.go
Expand Up @@ -125,9 +125,21 @@ func compareHosts(t *testing.T, received []description.Server, expected []string
}

func TestPollingSRVRecordsSpec(t *testing.T) {
for _, uri := range []string{
"mongodb+srv://test1.test.build.10gen.cc/?heartbeatFrequencyMS=100",
// Test with user:pass as a regression test for GODRIVER-2620
"mongodb+srv://user:pass@test1.test.build.10gen.cc/?heartbeatFrequencyMS=100",
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} {
t.Run(uri, func(t *testing.T) {
testPollingSRVRecordsSpec(t, uri)
})
}
}

func testPollingSRVRecordsSpec(t *testing.T, uri string) {
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t.Helper()
for _, tt := range srvPollingTests {
t.Run(tt.name, func(t *testing.T) {
uri := "mongodb+srv://test1.test.build.10gen.cc/?heartbeatFrequencyMS=100"
cfg, err := NewConfig(options.Client().ApplyURI(uri), nil)
require.NoError(t, err, "error constructing topology configs: %v", err)

Expand Down
27 changes: 18 additions & 9 deletions x/mongo/driver/topology/topology.go
Expand Up @@ -14,6 +14,8 @@ import (
"context"
"errors"
"fmt"
"net"
"net/url"
"strings"
"sync"
"sync/atomic"
Expand Down Expand Up @@ -234,7 +236,21 @@ func (t *Topology) Connect() error {

t.serversLock.Unlock()
if t.pollingRequired {
go t.pollSRVRecords()
uri, err := url.Parse(t.cfg.URI)
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I'm concerned we don't have enough test coverage of MongoDB connection string formats in the SRV polling tests to assert that it's safe to use url.Parse.

Is every mongodb+srv:// connection string parseable with url.Parse?

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The package doc says url.Parse parses [scheme:][//[userinfo@]host][/]path[?query][#fragment].
It has been proven that mongodb+srv is parseable as a legal scheme, and covered in the test cases.
Mongo host in the connection string may be different from ordinary hostnames, e.g. a comma-separated host list. However, it is illegal for SRV, and should be sanity checked by topology.NewConfig before being passed in Connect().
Also, we don't need to parse the path string in this case so it doesn't impact us even though we may have special cases in the query parameters.

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Sounds good. I also tested out using url.Parse to parse a bunch of connection string formats and they all worked correctly (see here).

if err != nil {
return err
}
// sanity check before passing the hostname to resolver
if parsedHosts := strings.Split(uri.Host, ","); len(parsedHosts) != 1 {
return fmt.Errorf("URI with SRV must include one and only one hostname")
}
_, _, err = net.SplitHostPort(uri.Host)
if err == nil {
// we were able to successfully extract a port from the host,
// but should not be able to when using SRV
return fmt.Errorf("URI with srv must not include a port number")
}
go t.pollSRVRecords(uri.Host)
t.pollingwg.Add(1)
}

Expand Down Expand Up @@ -556,7 +572,7 @@ func (t *Topology) selectServerFromDescription(desc description.Topology,
return suitable, nil
}

func (t *Topology) pollSRVRecords() {
func (t *Topology) pollSRVRecords(hosts string) {
defer t.pollingwg.Done()

serverConfig := newServerConfig(t.cfg.ServerOpts...)
Expand All @@ -573,13 +589,6 @@ func (t *Topology) pollSRVRecords() {
}
}()

// remove the scheme
uri := t.cfg.URI[14:]
hosts := uri
if idx := strings.IndexAny(uri, "/?@"); idx != -1 {
hosts = uri[:idx]
}

for {
select {
case <-pollTicker.C:
Expand Down