Add systctl support for services

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/compose/convert/service.go

@@ -151,6 +151,7 @@ func Service(
 				Privileges:      &privileges,
 				Isolation:       container.Isolation(service.Isolation),
 				Init:            service.Init,
+				Sysctls:         service.Sysctls,
 			},
 			LogDriver:     logDriver,
 			Resources:     resources,

cli/compose/loader/full-example.yml

@@ -240,6 +240,10 @@ services:
 
     stop_signal: SIGUSR1
 
+    sysctls:
+      net.core.somaxconn: 1024
+      net.ipv4.tcp_syncookies: 0
+
     # String or list
     # tmpfs: /run
     tmpfs:

cli/compose/loader/full-struct_test.go

@@ -346,8 +346,12 @@ func services(workingDir, homeDir string) []types.ServiceConfig {
 			StdinOpen:       true,
 			StopSignal:      "SIGUSR1",
 			StopGracePeriod: durationPtr(20 * time.Second),
-			Tmpfs:           []string{"/run", "/tmp"},
-			Tty:             true,
+			Sysctls: map[string]string{
+				"net.core.somaxconn":      "1024",
+				"net.ipv4.tcp_syncookies": "0",
+			},
+			Tmpfs: []string{"/run", "/tmp"},
+			Tty:   true,
 			Ulimits: map[string]*types.UlimitsConfig{
 				"nproc": {
 					Single: 65535,
@@ -756,6 +760,9 @@ services:
     stdin_open: true
     stop_grace_period: 20s
     stop_signal: SIGUSR1
+    sysctls:
+      net.core.somaxconn: "1024"
+      net.ipv4.tcp_syncookies: "0"
     tmpfs:
     - /run
     - /tmp
@@ -1325,6 +1332,10 @@ func fullExampleJSON(workingDir string) string {
       "stdin_open": true,
       "stop_grace_period": "20s",
       "stop_signal": "SIGUSR1",
+      "sysctls": {
+        "net.core.somaxconn": "1024",
+        "net.ipv4.tcp_syncookies": "0"
+      },
       "tmpfs": [
         "/run",
         "/tmp"

cli/compose/loader/loader.go

@@ -304,6 +304,7 @@ func createTransformHook(additionalTransformers ...Transformer) mapstructure.Dec
 		reflect.TypeOf(types.ServiceConfigObjConfig{}):           transformStringSourceMap,
 		reflect.TypeOf(types.StringOrNumberList{}):               transformStringOrNumberList,
 		reflect.TypeOf(map[string]*types.ServiceNetworkConfig{}): transformServiceNetworkMap,
+		reflect.TypeOf(types.Mapping{}):                          transformMappingOrListFunc("=", false),
 		reflect.TypeOf(types.MappingWithEquals{}):                transformMappingOrListFunc("=", true),
 		reflect.TypeOf(types.Labels{}):                           transformMappingOrListFunc("=", false),
 		reflect.TypeOf(types.MappingWithColon{}):                 transformMappingOrListFunc(":", false),

cli/compose/loader/loader_test.go

@@ -1461,6 +1461,47 @@ services:
 	}
 }
 
+func TestLoadSysctls(t *testing.T) {
+	config, err := loadYAML(`
+version: "3.8"
+services:
+  web:
+    image: busybox
+    sysctls:
+      - net.core.somaxconn=1024
+      - net.ipv4.tcp_syncookies=0
+      - testing.one.one=
+      - testing.one.two
+`)
+	assert.NilError(t, err)
+
+	expected := types.Mapping{
+		"net.core.somaxconn":      "1024",
+		"net.ipv4.tcp_syncookies": "0",
+		"testing.one.one":         "",
+		"testing.one.two":         "",
+	}
+
+	assert.Assert(t, is.Len(config.Services, 1))
+	assert.Check(t, is.DeepEqual(expected, config.Services[0].Sysctls))
+
+	config, err = loadYAML(`
+version: "3.8"
+services:
+  web:
+    image: busybox
+    sysctls:
+      net.core.somaxconn: 1024
+      net.ipv4.tcp_syncookies: 0
+      testing.one.one: ""
+      testing.one.two:
+`)
+	assert.NilError(t, err)
+
+	assert.Assert(t, is.Len(config.Services, 1))
+	assert.Check(t, is.DeepEqual(expected, config.Services[0].Sysctls))
+}
+
 func TestTransform(t *testing.T) {
 	var source = []interface{}{
 		"80-82:8080-8082",

cli/compose/types/types.go

@@ -24,7 +24,6 @@ var UnsupportedProperties = []string{
 	"restart",
 	"security_opt",
 	"shm_size",
-	"sysctls",
 	"ulimits",
 	"userns_mode",
 }
@@ -200,7 +199,7 @@ type ServiceConfig struct {
 	StdinOpen       bool                             `mapstructure:"stdin_open" yaml:"stdin_open,omitempty" json:"stdin_open,omitempty"`
 	StopGracePeriod *Duration                        `mapstructure:"stop_grace_period" yaml:"stop_grace_period,omitempty" json:"stop_grace_period,omitempty"`
 	StopSignal      string                           `mapstructure:"stop_signal" yaml:"stop_signal,omitempty" json:"stop_signal,omitempty"`
-	Sysctls         StringList                       `yaml:",omitempty" json:"sysctls,omitempty"`
+	Sysctls         Mapping                          `yaml:",omitempty" json:"sysctls,omitempty"`
 	Tmpfs           StringList                       `yaml:",omitempty" json:"tmpfs,omitempty"`
 	Tty             bool                             `mapstructure:"tty" yaml:"tty,omitempty" json:"tty,omitempty"`
 	Ulimits         map[string]*UlimitsConfig        `yaml:",omitempty" json:"ulimits,omitempty"`
@@ -240,6 +239,12 @@ type StringOrNumberList []string
 // For the key without value (`key`), the mapped value is set to nil.
 type MappingWithEquals map[string]*string
 
+// Mapping is a mapping type that can be converted from a list of
+// key[=value] strings.
+// For the key with an empty value (`key=`), or key without value (`key`), the
+// mapped value is set to an empty string `""`.
+type Mapping map[string]string
+
 // Labels is a mapping type for labels
 type Labels map[string]string