Expose plugin load timeout as a configurable option

control/config.go

@@ -40,6 +40,7 @@ const (
 	defaultListenAddr        string        = "127.0.0.1"
 	defaultListenPort        int           = 8082
 	defaultMaxRunningPlugins int           = 3
+	defaultPluginLoadTimeout int           = 3
 	defaultPluginTrust       int           = 1
 	defaultAutoDiscoverPath  string        = ""
 	defaultKeyringPaths      string        = ""
@@ -70,6 +71,7 @@ type pluginConfigItem struct {
 //         match the field mapping that is defined here
 type Config struct {
 	MaxRunningPlugins int               `json:"max_running_plugins"yaml:"max_running_plugins"`
+	PluginLoadTimeout int               `json:"plugin_load_timeout"yaml:"plugin_load_timeout"`
 	PluginTrust       int               `json:"plugin_trust_level"yaml:"plugin_trust_level"`
 	AutoDiscoverPath  string            `json:"auto_discover_path"yaml:"auto_discover_path"`
 	KeyringPaths      string            `json:"keyring_paths"yaml:"keyring_paths"`
@@ -99,6 +101,11 @@ const (
 						"type": "integer",
 						"minimum": 1
 					},
+					"plugin_load_timeout": {
+						"type": "integer",
+						"minimum": 3,
+						"maximum": 60
+					},
 					"keyring_paths" : {
 						"type": "string"
 					},
@@ -125,6 +132,7 @@ func GetDefaultConfig() *Config {
 		ListenAddr:        defaultListenAddr,
 		ListenPort:        defaultListenPort,
 		MaxRunningPlugins: defaultMaxRunningPlugins,
+		PluginLoadTimeout: defaultPluginLoadTimeout,
 		PluginTrust:       defaultPluginTrust,
 		AutoDiscoverPath:  defaultAutoDiscoverPath,
 		KeyringPaths:      defaultKeyringPaths,
@@ -151,6 +159,10 @@ func (c *Config) UnmarshalJSON(data []byte) error {
 			if err := json.Unmarshal(v, &(c.MaxRunningPlugins)); err != nil {
 				return fmt.Errorf("%v (while parsing 'control::max_running_plugins')", err)
 			}
+		case "plugin_load_timeout":
+			if err := json.Unmarshal(v, &(c.PluginLoadTimeout)); err != nil {
+				return fmt.Errorf("%v (while parsing 'control::plugin_load_timeout')", err)
+			}
 		case "plugin_trust_level":
 			if err := json.Unmarshal(v, &(c.PluginTrust)); err != nil {
 				return fmt.Errorf("%v (while parsing 'control::plugin_trust_level')", err)
@@ -179,7 +191,6 @@ func (c *Config) UnmarshalJSON(data []byte) error {
 			if err := json.Unmarshal(v, &(c.ListenPort)); err != nil {
 				return err
 			}
-
 		default:
 			return fmt.Errorf("Unrecognized key '%v' in global config file while parsing 'control'", k)
 		}

control/control.go

@@ -127,6 +127,7 @@ type managesPlugins interface {
 	SetMetricCatalog(catalogsMetrics)
 	GenerateArgs(logLevel int) plugin.Arg
 	SetPluginConfig(*pluginConfig)
+	SetPluginLoadTimeout(int)
 }
 
 type catalogsMetrics interface {
@@ -172,6 +173,7 @@ func OptSetConfig(cfg *Config) PluginControlOpt {
 	return func(c *pluginControl) {
 		c.Config = cfg
 		c.pluginManager.SetPluginConfig(cfg.Plugins)
+		c.pluginManager.SetPluginLoadTimeout(c.Config.PluginLoadTimeout)
 	}
 }
 

control/control_test.go

@@ -73,6 +73,7 @@ func (m *MockPluginManagerBadSwap) UnloadPlugin(c core.Plugin) (*loadedPlugin, s
 func (m *MockPluginManagerBadSwap) get(string) (*loadedPlugin, error) { return nil, nil }
 func (m *MockPluginManagerBadSwap) teardown()                         {}
 func (m *MockPluginManagerBadSwap) SetPluginConfig(*pluginConfig)     {}
+func (m *MockPluginManagerBadSwap) SetPluginLoadTimeout(int)          {}
 func (m *MockPluginManagerBadSwap) SetMetricCatalog(catalogsMetrics)  {}
 func (m *MockPluginManagerBadSwap) SetEmitter(gomit.Emitter)          {}
 func (m *MockPluginManagerBadSwap) GenerateArgs(int) plugin.Arg       { return plugin.Arg{} }

control/flags.go

@@ -31,6 +31,11 @@ var (
 		Usage:  fmt.Sprintf("The maximum number of instances of a loaded plugin to run (default: %v)", defaultMaxRunningPlugins),
 		EnvVar: "SNAP_MAX_PLUGINS",
 	}
+	flPluginLoadTimeout = cli.StringFlag{
+		Name:   "plugin-load-timeout",
+		Usage:  fmt.Sprintf("The maximum number seconds a plugin can take to load (default: %v)", defaultPluginLoadTimeout),
+		EnvVar: "SNAP_PLUGIN_LOAD_TIMEOUT",
+	}
 	flPluginTrust = cli.StringFlag{
 		Name:   "plugin-trust, t",
 		Usage:  fmt.Sprintf("0-2 (Disabled, Enabled, Warning; default: %v)", defaultPluginTrust),
@@ -65,5 +70,5 @@ var (
 		EnvVar: "SNAP_CONTROL_LISTEN_ADDR",
 	}
 
-	Flags = []cli.Flag{flNumberOfPLs, flAutoDiscover, flPluginTrust, flKeyringPaths, flCache, flControlRpcPort, flControlRpcAddr}
+	Flags = []cli.Flag{flNumberOfPLs, flPluginLoadTimeout, flAutoDiscover, flPluginTrust, flKeyringPaths, flCache, flControlRpcPort, flControlRpcAddr}
 )

control/plugin_manager.go

@@ -231,10 +231,11 @@ func (lp *loadedPlugin) Policy() *cpolicy.ConfigPolicy {
 // the struct representing the object responsible for
 // loading and unloading plugins
 type pluginManager struct {
-	metricCatalog catalogsMetrics
-	loadedPlugins *loadedPlugins
-	logPath       string
-	pluginConfig  *pluginConfig
+	pluginLoadTimeout int
+	metricCatalog     catalogsMetrics
+	loadedPlugins     *loadedPlugins
+	logPath           string
+	pluginConfig      *pluginConfig
 }
 
 func newPluginManager(opts ...pluginManagerOpt) *pluginManager {
@@ -243,9 +244,10 @@ func newPluginManager(opts ...pluginManagerOpt) *pluginManager {
 		logPath = `c:\temp`
 	}
 	p := &pluginManager{
-		loadedPlugins: newLoadedPlugins(),
-		logPath:       logPath,
-		pluginConfig:  newPluginConfig(),
+		pluginLoadTimeout: defaultPluginLoadTimeout,
+		loadedPlugins:     newLoadedPlugins(),
+		logPath:           logPath,
+		pluginConfig:      newPluginConfig(),
 	}
 
 	for _, opt := range opts {
@@ -264,6 +266,11 @@ func OptSetPluginConfig(cf *pluginConfig) pluginManagerOpt {
 	}
 }
 
+// SetPluginLoadTimeout sets plugin load timeout
+func (p *pluginManager) SetPluginLoadTimeout(to int) {
+	p.pluginLoadTimeout = to
+}
+
 // SetPluginConfig sets plugin config
 func (p *pluginManager) SetPluginConfig(cf *pluginConfig) {
 	p.pluginConfig = cf
@@ -294,7 +301,11 @@ func (p *pluginManager) LoadPlugin(details *pluginDetails, emitter gomit.Emitter
 		return nil, serror.New(err)
 	}
 
-	resp, err := ePlugin.Run(time.Second * 3)
+	pmLogger.WithFields(log.Fields{
+		"_block": "load-plugin",
+		"path":   filepath.Base(lPlugin.Details.Exec),
+	}).Debug(fmt.Sprintf("plugin load timeout set to %ds", p.pluginLoadTimeout))
+	resp, err := ePlugin.Run(time.Second * time.Duration(p.pluginLoadTimeout))
 	if err != nil {
 		pmLogger.WithFields(log.Fields{
 			"_block": "load-plugin",

docs/SNAPD.md

@@ -36,6 +36,7 @@ $ $SNAP_PATH/bin/snapd [global options] command [command options] [arguments...]
 --max-procs, -c '1'                          Set max cores to use for snap Agent. Default is 1 core. [$GOMAXPROCS]
 --auto-discover, -a                          Auto discover paths separated by colons. [$SNAP_AUTODISCOVER_PATH]
 --max-running-plugins, -m '3'                The maximum number of instances of a loaded plugin to run [$SNAP_MAX_PLUGINS]
+--plugin-load-timeout '3'                    The maximum number of seconds a plugin can take to load [$SNAP_PLUGIN_LOAD_TIMEOUT]
 --cache-expiration '500ms'                   The time limit for which a metric cache entry is valid [$SNAP_CACHE_EXPIRATION]
 --plugin-trust, -t '1'                       0-2 (Disabled, Enabled, Warning) [$SNAP_TRUST_LEVEL]
 --keyring-paths, -k                          Keyring paths for signing verification separated by colons [$SNAP_KEYRING_PATHS]

docs/SNAPD_CONFIGURATION.md

@@ -83,6 +83,10 @@ control:
   # plugin loaded in the system. Default value is 3
   max_running_plugins: 3
 
+  # plugin_load_timeout sets the maximal time allowed for a plugin to load
+  # Default value is 3
+  plugin_load_timeout: 10
+
   # keyring_paths sets the directory(s) to search for keyring files for signed
   # plugins. This can be a comma separated list of directories
   keyring_paths: /opt/snap/plugins/keyrings

examples/configs/snap-config-sample.json

@@ -10,6 +10,7 @@
         "listen_addr": "0.0.0.0",
 	"listen_port": 10082,
 	"max_running_plugins": 1,
+	"plugin_load_timeout": 10,
         "keyring_paths": "/some/path/with/keyring/files",
         "plugin_trust_level": 0,
         "plugins": {

examples/configs/snap-config-sample.yaml

@@ -47,6 +47,10 @@ control:
   # plugin loaded in the system. Default value is 3
   max_running_plugins: 1
 
+  # plugin_load_timeout sets the maximal time allowed for a plugin to load
+  # Default value is 3
+  plugin_load_timeout: 10
+
   # keyring_paths sets the directory(s) to search for keyring files for signed
   # plugins. This can be a comma separated list of directories
   keyring_paths: /some/path/with/keyring/files

snapd.go

@@ -754,6 +754,7 @@ func applyCmdLineFlags(cfg *Config, ctx *cli.Context) {
 	cfg.LogColors = setBoolVal(cfg.LogColors, ctx, "log-colors")
 	// next for the flags related to the control package
 	cfg.Control.MaxRunningPlugins = setIntVal(cfg.Control.MaxRunningPlugins, ctx, "max-running-plugins")
+	cfg.Control.PluginLoadTimeout = setIntVal(cfg.Control.PluginLoadTimeout, ctx, "plugin-load-timeout")
 	cfg.Control.PluginTrust = setIntVal(cfg.Control.PluginTrust, ctx, "plugin-trust")
 	cfg.Control.AutoDiscoverPath = setStringVal(cfg.Control.AutoDiscoverPath, ctx, "auto-discover")
 	cfg.Control.KeyringPaths = setStringVal(cfg.Control.KeyringPaths, ctx, "keyring-paths")