Merge pull request #4273 from mheon/no_runtime

Add a MissingRuntime implementation

6 files changed, 235 insertions, 35 deletions

diff --git a/libpod/boltdb_state_internal.go b/libpod/boltdb_state_internal.go
index ed87373e9..3347a3648 100644
--- a/libpod/boltdb_state_internal.go
+++ b/libpod/boltdb_state_internal.go
@@ -396,7 +396,11 @@ func (s *BoltState) getContainerFromDB(id []byte, ctr *Container, ctrsBkt *bolt.
 
 		ociRuntime, ok := s.runtime.ociRuntimes[runtimeName]
 		if !ok {
-			return errors.Wrapf(define.ErrOCIRuntimeUnavailable, "cannot find OCI runtime %q for container %s", ctr.config.OCIRuntime, ctr.ID())
+			// Use a MissingRuntime implementation
+			ociRuntime, err = getMissingRuntime(runtimeName, s.runtime)
+			if err != nil {
+				return err
+			}
 		}
 		ctr.ociRuntime = ociRuntime
 	}
diff --git a/libpod/container_api.go b/libpod/container_api.go
index 04c796410..759a7067e 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -656,7 +656,7 @@ func (c *Container) Sync() error {
 		(c.state.State != define.ContainerStateConfigured) &&
 		(c.state.State != define.ContainerStateExited) {
 		oldState := c.state.State
-		if err := c.ociRuntime.UpdateContainerStatus(c, true); err != nil {
+		if err := c.ociRuntime.UpdateContainerStatus(c); err != nil {
 			return err
 		}
 		// Only save back to DB if state changed
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index a7ac23f73..0043c9651 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -252,7 +252,7 @@ func (c *Container) waitForExitFileAndSync() error {
 		return err
 	}
 
-	if err := c.ociRuntime.UpdateContainerStatus(c, false); err != nil {
+	if err := c.checkExitFile(); err != nil {
 		return err
 	}
 
@@ -386,10 +386,11 @@ func (c *Container) syncContainer() error {
 		(c.state.State != define.ContainerStateConfigured) &&
 		(c.state.State != define.ContainerStateExited) {
 		oldState := c.state.State
-		// TODO: optionally replace this with a stat for the exit file
-		if err := c.ociRuntime.UpdateContainerStatus(c, false); err != nil {
+
+		if err := c.checkExitFile(); err != nil {
 			return err
 		}
+
 		// Only save back to DB if state changed
 		if c.state.State != oldState {
 			// Check for a restart policy match
@@ -1811,3 +1812,35 @@ func (c *Container) sortUserVolumes(ctrSpec *spec.Spec) ([]*ContainerNamedVolume
 	}
 	return namedUserVolumes, userMounts
 }
+
+// Check for an exit file, and handle one if present
+func (c *Container) checkExitFile() error {
+	// If the container's not running, nothing to do.
+	if c.state.State != define.ContainerStateRunning && c.state.State != define.ContainerStatePaused {
+		return nil
+	}
+
+	exitFile, err := c.exitFilePath()
+	if err != nil {
+		return err
+	}
+
+	// Check for the exit file
+	info, err := os.Stat(exitFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Container is still running, no error
+			return nil
+		}
+
+		return errors.Wrapf(err, "error running stat on container %s exit file", c.ID())
+	}
+
+	// Alright, it exists. Transition to Stopped state.
+	c.state.State = define.ContainerStateStopped
+	c.state.PID = 0
+	c.state.ConmonPID = 0
+
+	// Read the exit file to get our stopped time and exit code.
+	return c.handleExitFile(exitFile, info)
+}
diff --git a/libpod/oci.go b/libpod/oci.go
index 37d04349f..9e761788e 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -26,7 +26,7 @@ type OCIRuntime interface {
 	// It includes a switch for whether to perform a hard query of the
 	// runtime. If unset, the exit file (if supported by the implementation)
 	// will be used.
-	UpdateContainerStatus(ctr *Container, useRuntime bool) error
+	UpdateContainerStatus(ctr *Container) error
 	// StartContainer starts the given container.
 	StartContainer(ctr *Container) error
 	// KillContainer sends the given signal to the given container.
diff --git a/libpod/oci_conmon_linux.go b/libpod/oci_conmon_linux.go
index 3606a9634..658a2fe4e 100644
--- a/libpod/oci_conmon_linux.go
+++ b/libpod/oci_conmon_linux.go
@@ -216,8 +216,8 @@ func (r *ConmonOCIRuntime) CreateContainer(ctr *Container, restoreOptions *Conta
 // If useRuntime is false, we will not directly hit runc to see the container's
 // status, but will instead only check for the existence of the conmon exit file
 // and update state to stopped if it exists.
-func (r *ConmonOCIRuntime) UpdateContainerStatus(ctr *Container, useRuntime bool) error {
-	exitFile, err := ctr.exitFilePath()
+func (r *ConmonOCIRuntime) UpdateContainerStatus(ctr *Container) error {
+	exitFile, err := r.ExitFilePath(ctr)
 	if err != nil {
 		return err
 	}
@@ -227,33 +227,6 @@ func (r *ConmonOCIRuntime) UpdateContainerStatus(ctr *Container, useRuntime bool
 		return err
 	}
 
-	// If not using the OCI runtime, we don't need to do most of this.
-	if !useRuntime {
-		// If the container's not running, nothing to do.
-		if ctr.state.State != define.ContainerStateRunning && ctr.state.State != define.ContainerStatePaused {
-			return nil
-		}
-
-		// Check for the exit file conmon makes
-		info, err := os.Stat(exitFile)
-		if err != nil {
-			if os.IsNotExist(err) {
-				// Container is still running, no error
-				return nil
-			}
-
-			return errors.Wrapf(err, "error running stat on container %s exit file", ctr.ID())
-		}
-
-		// Alright, it exists. Transition to Stopped state.
-		ctr.state.State = define.ContainerStateStopped
-		ctr.state.PID = 0
-		ctr.state.ConmonPID = 0
-
-		// Read the exit file to get our stopped time and exit code.
-		return ctr.handleExitFile(exitFile, info)
-	}
-
 	// Store old state so we know if we were already stopped
 	oldState := ctr.state.State
 
@@ -825,6 +798,7 @@ func (r *ConmonOCIRuntime) RuntimeInfo() (map[string]interface{}, error) {
 		"version": conmonVersion,
 	}
 	info["OCIRuntime"] = map[string]interface{}{
+		"name":    r.name,
 		"path":    r.path,
 		"package": runtimePackage,
 		"version": runtimeVersion,
diff --git a/libpod/oci_missing.go b/libpod/oci_missing.go
new file mode 100644
index 000000000..d4524cd34
--- /dev/null
+++ b/libpod/oci_missing.go
@@ -0,0 +1,189 @@
+package libpod
+
+import (
+	"fmt"
+	"path/filepath"
+	"sync"
+
+	"github.com/containers/libpod/libpod/define"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+var (
+	// Only create each missing runtime once.
+	// Creation makes error messages we don't want to duplicate.
+	missingRuntimes map[string]*MissingRuntime
+	// We need a lock for this
+	missingRuntimesLock sync.Mutex
+)
+
+// MissingRuntime is used when the OCI runtime requested by the container is
+// missing (not installed or not in the configuration file).
+type MissingRuntime struct {
+	// Name is the name of the missing runtime. Will be used in errors.
+	name string
+	// exitsDir is the directory for exit files.
+	exitsDir string
+}
+
+// Get a new MissingRuntime for the given name.
+// Requires a libpod Runtime so we can make a sane path for the exits dir.
+func getMissingRuntime(name string, r *Runtime) (OCIRuntime, error) {
+	missingRuntimesLock.Lock()
+	defer missingRuntimesLock.Unlock()
+
+	if missingRuntimes == nil {
+		missingRuntimes = make(map[string]*MissingRuntime)
+	}
+
+	runtime, ok := missingRuntimes[name]
+	if ok {
+		return runtime, nil
+	}
+
+	// Once for each missing runtime, we want to error.
+	logrus.Errorf("OCI Runtime %s is in use by a container, but is not available (not in configuration file or not installed)", name)
+
+	newRuntime := new(MissingRuntime)
+	newRuntime.name = name
+	newRuntime.exitsDir = filepath.Join(r.config.TmpDir, "exits")
+
+	missingRuntimes[name] = newRuntime
+
+	return newRuntime, nil
+}
+
+// Name is the name of the missing runtime
+func (r *MissingRuntime) Name() string {
+	return fmt.Sprintf("%s (missing/not available)", r.name)
+}
+
+// Path is not available as the runtime is missing
+func (r *MissingRuntime) Path() string {
+	return "(missing/not available)"
+}
+
+// CreateContainer is not available as the runtime is missing
+func (r *MissingRuntime) CreateContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) error {
+	return r.printError()
+}
+
+// UpdateContainerStatus is not available as the runtime is missing
+func (r *MissingRuntime) UpdateContainerStatus(ctr *Container) error {
+	return r.printError()
+}
+
+// StartContainer is not available as the runtime is missing
+func (r *MissingRuntime) StartContainer(ctr *Container) error {
+	return r.printError()
+}
+
+// KillContainer is not available as the runtime is missing
+// TODO: We could attempt to unix.Kill() the PID as recorded in the state if we
+// really want to smooth things out? Won't be perfect, but if the container has
+// a PID namespace it could be enough?
+func (r *MissingRuntime) KillContainer(ctr *Container, signal uint, all bool) error {
+	return r.printError()
+}
+
+// StopContainer is not available as the runtime is missing
+func (r *MissingRuntime) StopContainer(ctr *Container, timeout uint, all bool) error {
+	return r.printError()
+}
+
+// DeleteContainer is not available as the runtime is missing
+func (r *MissingRuntime) DeleteContainer(ctr *Container) error {
+	return r.printError()
+}
+
+// PauseContainer is not available as the runtime is missing
+func (r *MissingRuntime) PauseContainer(ctr *Container) error {
+	return r.printError()
+}
+
+// UnpauseContainer is not available as the runtime is missing
+func (r *MissingRuntime) UnpauseContainer(ctr *Container) error {
+	return r.printError()
+}
+
+// ExecContainer is not available as the runtime is missing
+func (r *MissingRuntime) ExecContainer(ctr *Container, sessionID string, options *ExecOptions) (int, chan error, error) {
+	return -1, nil, r.printError()
+}
+
+// ExecStopContainer is not available as the runtime is missing.
+// TODO: We can also investigate using unix.Kill() on the PID of the exec
+// session here if we want to make stopping containers possible. Won't be
+// perfect, though.
+func (r *MissingRuntime) ExecStopContainer(ctr *Container, sessionID string, timeout uint) error {
+	return r.printError()
+}
+
+// ExecContainerCleanup is not available as the runtime is missing
+func (r *MissingRuntime) ExecContainerCleanup(ctr *Container, sessionID string) error {
+	return r.printError()
+}
+
+// CheckpointContainer is not available as the runtime is missing
+func (r *MissingRuntime) CheckpointContainer(ctr *Container, options ContainerCheckpointOptions) error {
+	return r.printError()
+}
+
+// SupportsCheckpoint returns false as checkpointing requires a working runtime
+func (r *MissingRuntime) SupportsCheckpoint() bool {
+	return false
+}
+
+// SupportsJSONErrors returns false as there is no runtime to give errors
+func (r *MissingRuntime) SupportsJSONErrors() bool {
+	return false
+}
+
+// SupportsNoCgroups returns false as there is no runtime to create containers
+func (r *MissingRuntime) SupportsNoCgroups() bool {
+	return false
+}
+
+// AttachSocketPath does not work as there is no runtime to attach to.
+// (Theoretically we could follow ExitFilePath but there is no guarantee the
+// container is running and thus has an attach socket...)
+func (r *MissingRuntime) AttachSocketPath(ctr *Container) (string, error) {
+	return "", r.printError()
+}
+
+// ExecAttachSocketPath does not work as there is no runtime to attach to.
+// (Again, we could follow ExitFilePath, but no guarantee there is an existing
+// and running exec session)
+func (r *MissingRuntime) ExecAttachSocketPath(ctr *Container, sessionID string) (string, error) {
+	return "", r.printError()
+}
+
+// ExitFilePath returns the exit file path for containers.
+// Here, we mimic what ConmonOCIRuntime does, because there is a chance that the
+// container in question is still running happily (config file modified to
+// remove a runtime, for example). We can't find the runtime to do anything to
+// the container, but Conmon should still place an exit file for it.
+func (r *MissingRuntime) ExitFilePath(ctr *Container) (string, error) {
+	if ctr == nil {
+		return "", errors.Wrapf(define.ErrInvalidArg, "must provide a valid container to get exit file path")
+	}
+	return filepath.Join(r.exitsDir, ctr.ID()), nil
+}
+
+// RuntimeInfo returns information on the missing runtime
+func (r *MissingRuntime) RuntimeInfo() (map[string]interface{}, error) {
+	info := make(map[string]interface{})
+	info["OCIRuntime"] = map[string]interface{}{
+		"name":    r.name,
+		"path":    "missing",
+		"package": "missing",
+		"version": "missing",
+	}
+	return info, nil
+}
+
+// Return an error indicating the runtime is missing
+func (r *MissingRuntime) printError() error {
+	return errors.Wrapf(define.ErrOCIRuntimeNotFound, "runtime %s is missing", r.name)
+}