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Merged
RiRa12621 merged 1 commit into from
Apr 3, 2025
Merged

chore(cloud-init): truncate hostnames in determineHostname #1

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9 changes: 9 additions & 0 deletions coreos-cloudinit.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ import (
"log"
"os"
"runtime"
"strings"
"sync"
"time"

Expand Down Expand Up @@ -285,6 +286,14 @@ func determineHostname(md datasource.Metadata, udata *initialize.UserData) strin
hostname = udataHostname
}
}
if len(hostname) > 63 {
log.Printf("Hostname too long. Truncating hostname %s to %s", hostname, strings.Split(hostname, ".")[0])
hostname = strings.Split(hostname, ".")[0]
if len(hostname) > 63 {
log.Printf("Hostname still too long. Truncating hostname %s further to 63 bytes (%s)", hostname, hostname[:63])
hostname = hostname[:63]
}
}
return hostname
}

Expand Down
76 changes: 76 additions & 0 deletions coreos-cloudinit_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,10 @@ import (
"bytes"
"encoding/base64"
"errors"
"github.com/flatcar/coreos-cloudinit/datasource"
"github.com/flatcar/coreos-cloudinit/initialize"
"net"
"reflect"
"testing"
)

Expand Down Expand Up @@ -75,3 +79,75 @@ func TestDecompressIfGzip(t *testing.T) {
}

}

func TestDetermineHostname(t *testing.T) {
for _, tt := range []struct {
metaData datasource.Metadata
uData *initialize.UserData
expect string
}{
{
metaData: datasource.Metadata{
PublicIPv4: net.ParseIP("1.2.3.4"),
PublicIPv6: net.ParseIP("5.6.7.8"),
PrivateIPv4: net.ParseIP("1.2.3.4"),
PrivateIPv6: net.ParseIP("5.6.7.8"),
Hostname: "regular-name",
SSHPublicKeys: map[string]string{"my": "key"},
NetworkConfig: net.Interface{
Index: 0,
MTU: 0,
Name: "some-interface",
HardwareAddr: nil,
Flags: 0,
},
},
uData: nil,
expect: "regular-name",
},
{
metaData: datasource.Metadata{
PublicIPv4: net.ParseIP("1.2.3.4"),
PublicIPv6: net.ParseIP("5.6.7.8"),
PrivateIPv4: net.ParseIP("1.2.3.4"),
PrivateIPv6: net.ParseIP("5.6.7.8"),
Hostname: "this-hostname-is-larger-than-sixty-three-characters-long-and.will.be.truncated.locale",
SSHPublicKeys: map[string]string{"my": "key"},
NetworkConfig: net.Interface{
Index: 0,
MTU: 0,
Name: "some-interface",
HardwareAddr: nil,
Flags: 0,
},
},
uData: nil,
expect: "this-hostname-is-larger-than-sixty-three-characters-long-and",
},
{
metaData: datasource.Metadata{
PublicIPv4: net.ParseIP("1.2.3.4"),
PublicIPv6: net.ParseIP("5.6.7.8"),
PrivateIPv4: net.ParseIP("1.2.3.4"),
PrivateIPv6: net.ParseIP("5.6.7.8"),
Hostname: "this-hostname-is-larger-than-sixty-three-characters-long-and-will-be-truncated.local",
SSHPublicKeys: map[string]string{"my": "key"},
NetworkConfig: net.Interface{
Index: 0,
MTU: 0,
Name: "some-interface",
HardwareAddr: nil,
Flags: 0,
},
},
uData: nil,
expect: "this-hostname-is-larger-than-sixty-three-characters-long-and-wi",
},
} {
hostname := determineHostname(tt.metaData, tt.uData)
if !reflect.DeepEqual(tt.expect, hostname) {
t.Fatalf("Bad hostname, want %s, got %s", tt.expect, hostname)
}

}
}
5 changes: 0 additions & 5 deletions datasource/metadata/ec2/metadata.go
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Original file line number Diff line number Diff line change
Expand Up @@ -78,11 +78,6 @@ func (ms metadataService) FetchMetadata() (datasource.Metadata, error) {
}

if hostname, err := ms.fetchAttribute(fmt.Sprintf("%s/hostname", ms.MetadataUrl())); err == nil {
hostname := strings.Split(hostname, ".")[0]
if len(hostname) > 63 {
log.Printf("Truncating hostname %s to 63 bytes (%s)", hostname, hostname[:63])
hostname = hostname[:63]
}
metadata.Hostname = hostname
} else if _, ok := err.(pkg.ErrNotFound); !ok {
return metadata, err
Expand Down
20 changes: 1 addition & 19 deletions datasource/metadata/ec2/metadata_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -188,25 +188,7 @@ func TestFetchMetadata(t *testing.T) {
"/2009-04-04/meta-data/public-keys/0/openssh-key": "key",
},
expect: datasource.Metadata{
Hostname: "host",
PrivateIPv4: net.ParseIP("1.2.3.4"),
PublicIPv4: net.ParseIP("5.6.7.8"),
SSHPublicKeys: map[string]string{"test1": "key"},
},
},
{
root: "/",
metadataPath: "2009-04-04/meta-data",
resources: map[string]string{
"/2009-04-04/meta-data/hostname": "this-hostname-is-larger-than-sixty-three-characters-long-and-will-be-truncated.local",
"/2009-04-04/meta-data/local-ipv4": "1.2.3.4",
"/2009-04-04/meta-data/public-ipv4": "5.6.7.8",
"/2009-04-04/meta-data/public-keys": "0=test1\n",
"/2009-04-04/meta-data/public-keys/0": "openssh-key",
"/2009-04-04/meta-data/public-keys/0/openssh-key": "key",
},
expect: datasource.Metadata{
Hostname: "this-hostname-is-larger-than-sixty-three-characters-long-and-wi",
Hostname: "host.local",
PrivateIPv4: net.ParseIP("1.2.3.4"),
PublicIPv4: net.ParseIP("5.6.7.8"),
SSHPublicKeys: map[string]string{"test1": "key"},
Expand Down