Add (unchecked) code to do an in-situ replacement of build settings

server/environment.go

@@ -14,6 +14,11 @@ type Environment interface {
 	// for this specific server instance.
 	IsRunning() (bool, error)
 
+	// Performs an update of server resource limits without actually stopping the server
+	// process. This only executes if the environment supports it, otherwise it is
+	// a no-op.
+	InSituUpdate() error
+
 	// Runs before the environment is started. If an error is returned starting will
 	// not occur, otherwise proceeds as normal.
 	OnBeforeStart() error

server/environment_docker.go

@@ -114,6 +114,35 @@ func (d *DockerEnvironment) IsRunning() (bool, error) {
 	return c.State.Running, nil
 }
 
+// Performs an in-place update of the Docker container's resource limits without actually
+// making any changes to the operational state of the container. This allows memory, cpu,
+// and IO limitations to be adjusted on the fly for individual instances.
+func (d *DockerEnvironment) InSituUpdate() error {
+	if _, err := d.Client.ContainerInspect(context.Background(), d.Server.Uuid); err != nil {
+		// If the container doesn't exist for some reason there really isn't anything
+		// we can do to fix that in this process (it doesn't make sense at least). In those
+		// cases just return without doing anything since we still want to save the configuration
+		// to the disk.
+		//
+		// We'll let a boot process make modifications to the container if needed at this point.
+		if client.IsErrNotFound(err) {
+			return nil
+		}
+
+		return errors.WithStack(err)
+	}
+
+	u := container.UpdateConfig{
+		Resources: d.getResourcesForServer(),
+	}
+
+	if _, err := d.Client.ContainerUpdate(context.Background(), d.Server.Uuid, u); err != nil {
+		return errors.WithStack(err)
+	}
+
+	return nil
+}
+
 // Run before the container starts and get the process configuration from the Panel.
 // This is important since we use this to check configuration files as well as ensure
 // we always have the latest version of an egg available for server processes.
@@ -412,8 +441,6 @@ func (d *DockerEnvironment) Create() error {
 		return errors.WithStack(err)
 	}
 
-	var oomDisabled = true
-
 	// Ensure the data directory exists before getting too far through this process.
 	if err := d.Server.Filesystem.EnsureDataDirectory(); err != nil {
 		return errors.WithStack(err)
@@ -477,19 +504,7 @@ func (d *DockerEnvironment) Create() error {
 
 		// Define resource limits for the container based on the data passed through
 		// from the Panel.
-		Resources: container.Resources{
-			// @todo memory limit should be slightly higher than the reservation
-			Memory:            d.Server.Build.MemoryLimit * 1000000,
-			MemoryReservation: d.Server.Build.MemoryLimit * 1000000,
-			MemorySwap:        d.Server.Build.ConvertedSwap(),
-
-			CPUQuota:  d.Server.Build.ConvertedCpuLimit(),
-			CPUPeriod: 100000,
-			CPUShares: 1024,
-
-			BlkioWeight:    d.Server.Build.IoWeight,
-			OomKillDisable: &oomDisabled,
-		},
+		Resources: d.getResourcesForServer(),
 
 		// @todo make this configurable again
 		DNS: []string{"1.1.1.1", "8.8.8.8"},
@@ -677,3 +692,26 @@ func (d *DockerEnvironment) exposedPorts() nat.PortSet {
 
 	return out
 }
+
+// Formats the resources available to a server instance in such as way that Docker will
+// generate a matching environment in the container.
+func (d *DockerEnvironment) getResourcesForServer() container.Resources {
+	b := true
+	oomDisabled := d.Server.Container.OomDisabled
+
+	if oomDisabled == nil {
+		oomDisabled = &b
+	}
+
+	return container.Resources{
+		// @todo memory limit should be slightly higher than the reservation
+		Memory:            d.Server.Build.MemoryLimit * 1000000,
+		MemoryReservation: d.Server.Build.MemoryLimit * 1000000,
+		MemorySwap:        d.Server.Build.ConvertedSwap(),
+		CPUQuota:  d.Server.Build.ConvertedCpuLimit(),
+		CPUPeriod: 100000,
+		CPUShares: 1024,
+		BlkioWeight:    d.Server.Build.IoWeight,
+		OomKillDisable: oomDisabled,
+	}
+}

server/server.go

@@ -13,6 +13,7 @@ import (
 	"os"
 	"path"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -43,6 +44,11 @@ type Server struct {
 	Container struct {
 		// Defines the Docker image that will be used for this server
 		Image string `json:"image,omitempty"`
+		// If set to true, OOM killer will be disabled on the server's Docker container.
+		// If not present (nil) we will default to disabling it.
+		OomDisabled *bool `json:"oom_disabled,omitempty"`
+		// Defines if the container needs to be rebuilt on the next boot.
+		RebuildRequired bool `json:"rebuild_required,omitempty"`
 	} `json:"container,omitempty"`
 
 	Environment Environment `json:"-" yaml:"-"`
@@ -62,6 +68,10 @@ type Server struct {
 	// fetched from the Pterodactyl Server instance each time the server process is
 	// started, and then cached here.
 	processConfiguration *api.ServerConfiguration
+
+	// Internal mutex used to block actions that need to occur sequentially, such as
+	// writing the configuration to the disk.
+	mutex *sync.Mutex
 }
 
 // The build settings for a given server that impact docker container creation and
@@ -179,11 +189,18 @@ func LoadDirectory(dir string, cfg *config.SystemConfiguration) ([]*Server, erro
 	return servers, nil
 }
 
+// Initializes the default required internal struct components for a Server.
+func (s *Server) Init() {
+	s.listeners = make(map[string][]EventListenerFunction)
+	s.mutex = &sync.Mutex{}
+}
+
 // Initalizes a server using a data byte array. This will be marshaled into the
 // given struct using a YAML marshaler. This will also configure the given environment
 // for a server.
 func FromConfiguration(data []byte, cfg *config.SystemConfiguration) (*Server, error) {
 	s := &Server{}
+	s.Init()
 
 	if err := yaml.Unmarshal(data, s); err != nil {
 		return nil, err
@@ -277,4 +294,4 @@ func (s *Server) SetState(state string) error {
 // Gets the process configuration data for the server.
 func (s *Server) GetProcessConfiguration() (*api.ServerConfiguration, error) {
 	return api.NewRequester().GetServerConfiguration(s.Uuid)
-}
+}

server/server_configuration.go

@@ -0,0 +1,31 @@
+package server
+
+import (
+	"github.com/pkg/errors"
+	"gopkg.in/yaml.v2"
+	"os"
+)
+
+// Writes the server configuration to the disk. The saved configuration will be returned
+// back to the calling function to use if desired.
+func (s *Server) WriteConfigurationToDisk() ([]byte, error) {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	f, err := os.Create("data/servers/" + s.Uuid + ".yml")
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+	defer f.Close()
+
+	b, err := yaml.Marshal(&s)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	if _, err := f.Write(b); err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return b, nil
+}

server/server_update.go

@@ -0,0 +1,34 @@
+package server
+
+import (
+	"encoding/json"
+	"github.com/imdario/mergo"
+	"github.com/pkg/errors"
+)
+
+// Merges data passed through in JSON form into the existing server object.
+// Any changes to the build settings will apply immediately in the environment
+// if the environment supports it.
+//
+// The server will be marked as requiring a rebuild on the next boot sequence,
+// it is up to the specific environment to determine what needs to happen when
+// that is the case.
+func (s *Server) UpdateDataStructure(data []byte) error {
+	src := Server{}
+	if err := json.Unmarshal(data, &src); err != nil {
+		return errors.WithStack(err)
+	}
+
+	// Merge the new data object that we have received with the existing server data object
+	// and then save it to the disk so it is persistent.
+	if err := mergo.Merge(&s, src); err != nil {
+		return errors.WithStack(err)
+	}
+
+	s.Container.RebuildRequired = true
+	if _, err := s.WriteConfigurationToDisk(); err != nil {
+		return errors.WithStack(err)
+	}
+
+	return s.Environment.InSituUpdate()
+}