chore: add dns config to inspect response

Signed-off-by: Arjun Raja Yogidas <[email protected]>

Author: coderbirju

cmd/nerdctl/container/container_inspect_linux_test.go

@@ -294,3 +294,51 @@ func TestContainerInspectHostConfigDefaults(t *testing.T) {
 	assert.Equal(t, int64(0), inspect.HostConfig.MemorySwap)
 	assert.Equal(t, bool(false), inspect.HostConfig.OomKillDisable)
 }
+
+func TestContainerInspectHostConfigDNS(t *testing.T) {
+	testContainer := testutil.Identifier(t)
+
+	base := testutil.NewBase(t)
+	defer base.Cmd("rm", "-f", testContainer).Run()
+
+	// Run a container with DNS options
+	base.Cmd("run", "-d", "--name", testContainer,
+		"--dns", "8.8.8.8",
+		"--dns", "1.1.1.1",
+		"--dns-search", "example.com",
+		"--dns-search", "test.local",
+		"--dns-option", "ndots:5",
+		"--dns-option", "timeout:3",
+		testutil.AlpineImage, "sleep", "infinity").AssertOK()
+
+	inspect := base.InspectContainer(testContainer)
+
+	// Check DNS servers
+	expectedDNSServers := []string{"8.8.8.8", "1.1.1.1"}
+	assert.DeepEqual(t, expectedDNSServers, inspect.HostConfig.DNS)
+
+	// Check DNS search domains
+	expectedDNSSearch := []string{"example.com", "test.local"}
+	assert.DeepEqual(t, expectedDNSSearch, inspect.HostConfig.DNSSearch)
+
+	// Check DNS options
+	expectedDNSOptions := []string{"ndots:5", "timeout:3"}
+	assert.DeepEqual(t, expectedDNSOptions, inspect.HostConfig.DNSOptions)
+}
+
+func TestContainerInspectHostConfigDNSDefaults(t *testing.T) {
+	testContainer := testutil.Identifier(t)
+
+	base := testutil.NewBase(t)
+	defer base.Cmd("rm", "-f", testContainer).Run()
+
+	// Run a container without specifying DNS options
+	base.Cmd("run", "-d", "--name", testContainer, testutil.AlpineImage, "sleep", "infinity").AssertOK()
+
+	inspect := base.InspectContainer(testContainer)
+
+	// Check that DNS settings are empty by default
+	assert.Equal(t, 0, len(inspect.HostConfig.DNS))
+	assert.Equal(t, 0, len(inspect.HostConfig.DNSSearch))
+	assert.Equal(t, 0, len(inspect.HostConfig.DNSOptions))
+}

pkg/cmd/container/create.go

@@ -626,19 +626,20 @@ type internalLabels struct {
 	extraHosts  []string
 	pidFile     string
 	blkioWeight uint16
-	cpusetCpus  string
-	cpusetMems  string
 	// labels from cmd options or automatically set
 	name     string
 	hostname string
 	// automatically generated
 	stateDir string
 	// network
-	networks   []string
-	ipAddress  string
-	ip6Address string
-	ports      []cni.PortMapping
-	macAddress string
+	networks             []string
+	ipAddress            string
+	ip6Address           string
+	ports                []cni.PortMapping
+	macAddress           string
+	dnsServers           []string
+	dnsSearchDomains     []string
+	dnsResolvConfOptions []string
 	// volume
 	mountPoints []*mountutil.Processed
 	anonVolumes []string
@@ -751,6 +752,30 @@ func withInternalLabels(internalLabels internalLabels) (containerd.NewContainerO
 		m[labels.CIdFile] = internalLabels.cidFile
 	}
 
+	if len(internalLabels.dnsServers) > 0 {
+		dnsServersJSON, err := json.Marshal(internalLabels.dnsServers)
+		if err != nil {
+			return nil, err
+		}
+		m[labels.DnsServer] = string(dnsServersJSON)
+	}
+
+	if len(internalLabels.dnsSearchDomains) > 0 {
+		dnsSearchJSON, err := json.Marshal(internalLabels.dnsSearchDomains)
+		if err != nil {
+			return nil, err
+		}
+		m[labels.DNSSearchDomains] = string(dnsSearchJSON)
+	}
+
+	if len(internalLabels.dnsResolvConfOptions) > 0 {
+		dnsResolvConfOptionsJSON, err := json.Marshal(internalLabels.dnsResolvConfOptions)
+		if err != nil {
+			return nil, err
+		}
+		m[labels.DNSResolvConfOptions] = string(dnsResolvConfOptionsJSON)
+	}
+
 	return containerd.WithAdditionalContainerLabels(m), nil
 }
 
@@ -762,6 +787,9 @@ func (il *internalLabels) loadNetOpts(opts types.NetworkOptions) {
 	il.ip6Address = opts.IP6Address
 	il.networks = opts.NetworkSlice
 	il.macAddress = opts.MACAddress
+	il.dnsServers = opts.DNSServers
+	il.dnsSearchDomains = opts.DNSSearchDomains
+	il.dnsResolvConfOptions = opts.DNSResolvConfOptions
 }
 
 func dockercompatMounts(mountPoints []*mountutil.Processed) []dockercompat.MountPoint {

pkg/inspecttypes/dockercompat/dockercompat.go

@@ -157,6 +157,9 @@ type HostConfig struct {
 	Memory          int64       // Memory limit (in bytes)
 	MemorySwap      int64       // Total memory usage (memory + swap); set `-1` to enable unlimited swap
 	OomKillDisable  bool        // specifies whether to disable OOM Killer
+	DNS             []string    `json:"Dns"`        // List of DNS server to lookup
+	DNSOptions      []string    `json:"DnsOptions"` // List of DNSOption to look for
+	DNSSearch       []string    `json:"DnsSearch"`  // List of DNSSearch to look for
 }
 
 // From https://github.com/moby/moby/blob/v20.10.1/api/types/types.go#L416-L427
@@ -224,6 +227,12 @@ type NetworkSettings struct {
 	Networks map[string]*NetworkEndpointSettings
 }
 
+type DNSSettings struct {
+	DNSServers           []string
+	DNSResolvConfOptions []string
+	DNSSearchDomains     []string
+}
+
 type CPUSettings struct {
 	cpuSetCpus string
 	cpuSetMems string
@@ -427,6 +436,16 @@ func ContainerFromNative(n *native.Container) (*Container, error) {
 	c.HostConfig.OomKillDisable = memorySettings.DisableOOMKiller
 	c.HostConfig.Memory = memorySettings.Limit
 	c.HostConfig.MemorySwap = memorySettings.Swap
+
+	dnsSettings, err := getDnsFromNative(n.Labels)
+	if err != nil {
+		return nil, fmt.Errorf("failed to Decode dns Settings: %v", err)
+	}
+
+	c.HostConfig.DNS = dnsSettings.DNSServers
+	c.HostConfig.DNSOptions = dnsSettings.DNSResolvConfOptions
+	c.HostConfig.DNSSearch = dnsSettings.DNSSearchDomains
+
 	c.State = cs
 	c.Config = &Config{
 		Labels: n.Labels,
@@ -685,6 +704,30 @@ func getMemorySettingsFromNative(sp *specs.Spec) (*MemorySetting, error) {
 	return res, nil
 }
 
+func getDnsFromNative(Labels map[string]string) (*DNSSettings, error) {
+	res := &DNSSettings{}
+
+	if dnsServers := Labels[labels.DnsServer]; dnsServers != "" {
+		if err := json.Unmarshal([]byte(dnsServers), &res.DNSServers); err != nil {
+			return nil, fmt.Errorf("failed to parse DNS servers: %v", err)
+		}
+	}
+
+	if dnsOptions := Labels[labels.DNSResolvConfOptions]; dnsOptions != "" {
+		if err := json.Unmarshal([]byte(dnsOptions), &res.DNSResolvConfOptions); err != nil {
+			return nil, fmt.Errorf("failed to parse DNS options: %v", err)
+		}
+	}
+
+	if dnsSearch := Labels[labels.DNSSearchDomains]; dnsSearch != "" {
+		if err := json.Unmarshal([]byte(dnsSearch), &res.DNSSearchDomains); err != nil {
+			return nil, fmt.Errorf("failed to parse DNS search domains: %v", err)
+		}
+	}
+
+	return res, nil
+}
+
 type IPAMConfig struct {
 	Subnet  string `json:"Subnet,omitempty"`
 	Gateway string `json:"Gateway,omitempty"`

pkg/labels/labels.go

@@ -112,4 +112,13 @@ const (
 
 	// Cidfile is the ContainerId file set via the --cidfile flag
 	CIdFile = Prefix + "cid-file"
+
+	// Custom DNS lookup servers.
+	DnsServer = Prefix + "dns"
+
+	// DNSResolvConfOptions set DNS options
+	DNSResolvConfOptions = Prefix + "dns-options"
+
+	// DNSSearchDomains set custom DNS search domains
+	DNSSearchDomains = Prefix + "dns-search"
 )