podman healthcheck run (phase 1)

Add the ability to manually run a container's healthcheck command.
This is only the first phase of implementing the healthcheck.
Subsequent pull requests will deal with the exposing the results and
history of healthchecks as well as the scheduling.

Signed-off-by: baude <bbaude@redhat.com>

4 files changed, 148 insertions, 0 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 75f4a4a4f..2381f53ad 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/containernetworking/cni/pkg/types"
 	cnitypes "github.com/containernetworking/cni/pkg/types/current"
+	"github.com/containers/image/manifest"
 	"github.com/containers/libpod/libpod/lock"
 	"github.com/containers/libpod/pkg/namespaces"
 	"github.com/containers/storage"
@@ -365,6 +366,9 @@ type ContainerConfig struct {
 
 	// Systemd tells libpod to setup the container in systemd mode
 	Systemd bool `json:"systemd"`
+
+	// HealtchCheckConfig has the health check command and related timings
+	HealthCheckConfig *manifest.Schema2HealthConfig
 }
 
 // ContainerStatus returns a string representation for users
@@ -1085,3 +1089,14 @@ func (c *Container) ContainerState() (*ContainerState, error) {
 	deepcopier.Copy(c.state).To(returnConfig)
 	return c.state, nil
 }
+
+// HasHealthCheck returns bool as to whether there is a health check
+// defined for the container
+func (c *Container) HasHealthCheck() bool {
+	return c.config.HealthCheckConfig != nil
+}
+
+// HealthCheckConfig returns the command and timing attributes of the health check
+func (c *Container) HealthCheckConfig() *manifest.Schema2HealthConfig {
+	return c.config.HealthCheckConfig
+}
diff --git a/libpod/healthcheck.go b/libpod/healthcheck.go
new file mode 100644
index 000000000..81addb9a8
--- /dev/null
+++ b/libpod/healthcheck.go
@@ -0,0 +1,92 @@
+package libpod
+
+import (
+	"os"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// HealthCheckStatus represents the current state of a container
+type HealthCheckStatus int
+
+const (
+	// HealthCheckSuccess means the health worked
+	HealthCheckSuccess HealthCheckStatus = iota
+	// HealthCheckFailure means the health ran and failed
+	HealthCheckFailure HealthCheckStatus = iota
+	// HealthCheckContainerStopped means the health check cannot
+	// be run because the container is stopped
+	HealthCheckContainerStopped HealthCheckStatus = iota
+	// HealthCheckContainerNotFound means the container could
+	// not be found in local store
+	HealthCheckContainerNotFound HealthCheckStatus = iota
+	// HealthCheckNotDefined means the container has no health
+	// check defined in it
+	HealthCheckNotDefined HealthCheckStatus = iota
+	// HealthCheckInternalError means somes something failed obtaining or running
+	// a given health check
+	HealthCheckInternalError HealthCheckStatus = iota
+	// HealthCheckDefined means the healthcheck was found on the container
+	HealthCheckDefined HealthCheckStatus = iota
+)
+
+// HealthCheck verifies the state and validity of the healthcheck configuration
+// on the container and then executes the healthcheck
+func (r *Runtime) HealthCheck(name string) (HealthCheckStatus, error) {
+	container, err := r.LookupContainer(name)
+	if err != nil {
+		return HealthCheckContainerNotFound, errors.Wrapf(err, "unable to lookup %s to perform a health check", name)
+	}
+	hcStatus, err := checkHealthCheckCanBeRun(container)
+	if err == nil {
+		return container.RunHealthCheck()
+	}
+	return hcStatus, err
+}
+
+// RunHealthCheck runs the health check as defined by the container
+func (c *Container) RunHealthCheck() (HealthCheckStatus, error) {
+	var newCommand []string
+	hcStatus, err := checkHealthCheckCanBeRun(c)
+	if err != nil {
+		return hcStatus, err
+	}
+	hcCommand := c.HealthCheckConfig().Test
+	if len(hcCommand) > 0 && hcCommand[0] == "CMD-SHELL" {
+		newCommand = []string{"sh", "-c"}
+		newCommand = append(newCommand, hcCommand[1:]...)
+	} else {
+		newCommand = hcCommand
+	}
+	// TODO when history/logging is implemented for healthcheck, we need to change the output streams
+	// so we can capture i/o
+	streams := new(AttachStreams)
+	streams.OutputStream = os.Stdout
+	streams.ErrorStream = os.Stderr
+	streams.InputStream = os.Stdin
+	streams.AttachOutput = true
+	streams.AttachError = true
+	streams.AttachInput = true
+
+	logrus.Debugf("executing health check command %s for %s", strings.Join(newCommand, " "), c.ID())
+	if err := c.Exec(false, false, []string{}, newCommand, "", "", streams, 0); err != nil {
+		return HealthCheckFailure, err
+	}
+	return HealthCheckSuccess, nil
+}
+
+func checkHealthCheckCanBeRun(c *Container) (HealthCheckStatus, error) {
+	cstate, err := c.State()
+	if err != nil {
+		return HealthCheckInternalError, err
+	}
+	if cstate != ContainerStateRunning {
+		return HealthCheckContainerStopped, errors.Errorf("container %s is not running", c.ID())
+	}
+	if !c.HasHealthCheck() {
+		return HealthCheckNotDefined, errors.Errorf("container %s has no defined healthcheck", c.ID())
+	}
+	return HealthCheckDefined, nil
+}
diff --git a/libpod/image/image.go b/libpod/image/image.go
index b20419d7b..8c98de3d3 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -1151,3 +1151,32 @@ func (i *Image) Save(ctx context.Context, source, format, output string, moreTag
 
 	return nil
 }
+
+// GetConfigBlob returns a schema2image.  If the image is not a schema2, then
+// it will return an error
+func (i *Image) GetConfigBlob(ctx context.Context) (*manifest.Schema2Image, error) {
+	imageRef, err := i.toImageRef(ctx)
+	if err != nil {
+		return nil, err
+	}
+	b, err := imageRef.ConfigBlob(ctx)
+	if err != nil {
+		return nil, errors.Wrapf(err, "unable to get config blob for %s", i.ID())
+	}
+	blob := manifest.Schema2Image{}
+	if err := json.Unmarshal(b, &blob); err != nil {
+		return nil, errors.Wrapf(err, "unable to parse image blob for %s", i.ID())
+	}
+	return &blob, nil
+
+}
+
+// GetHealthCheck returns a HealthConfig for an image.  This function only works with
+// schema2 images.
+func (i *Image) GetHealthCheck(ctx context.Context) (*manifest.Schema2HealthConfig, error) {
+	configBlob, err := i.GetConfigBlob(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return configBlob.ContainerConfig.Healthcheck, nil
+}
diff --git a/libpod/options.go b/libpod/options.go
index 1e8592a25..5ad2824d9 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -7,6 +7,7 @@ import (
 	"regexp"
 	"syscall"
 
+	"github.com/containers/image/manifest"
 	"github.com/containers/libpod/pkg/namespaces"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/idtools"
@@ -1469,3 +1470,14 @@ func WithInfraContainerPorts(bindings []ocicni.PortMapping) PodCreateOption {
 		return nil
 	}
 }
+
+// WithHealthCheck adds the healthcheck to the container config
+func WithHealthCheck(healthCheck *manifest.Schema2HealthConfig) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+		ctr.config.HealthCheckConfig = healthCheck
+		return nil
+	}
+}