added healthcheck to config struct and healthcheck struct (#138)

* added healthcheck to config struct and healthcheck struct

* added test tag to HealthConfig Test

* Revert "added test tag to HealthConfig Test"

This reverts commit 94957d1.

v1/config.go

@@ -64,6 +64,27 @@ type RootFS struct {
 	DiffIDs []Hash `json:"diff_ids"`
 }
 
+// HealthConfig holds configuration settings for the HEALTHCHECK feature.
+type HealthConfig struct {
+	// Test is the test to perform to check that the container is healthy.
+	// An empty slice means to inherit the default.
+	// The options are:
+	// {} : inherit healthcheck
+	// {"NONE"} : disable healthcheck
+	// {"CMD", args...} : exec arguments directly
+	// {"CMD-SHELL", command} : run command with system's default shell
+	Test []string `json:",omitempty"`
+
+	// Zero means to inherit. Durations are expressed as integer nanoseconds.
+	Interval    time.Duration `json:",omitempty"` // Interval is the time to wait between checks.
+	Timeout     time.Duration `json:",omitempty"` // Timeout is the time to wait before considering the check to have hung.
+	StartPeriod time.Duration `json:",omitempty"` // The start period for the container to initialize before the retries starts to count down.
+
+	// Retries is the number of consecutive failures needed to consider a container as unhealthy.
+	// Zero means inherit.
+	Retries int `json:",omitempty"`
+}
+
 // Config is a submessage of the config file described as:
 //   The execution parameters which SHOULD be used as a base when running
 //   a container using the image.
@@ -77,6 +98,7 @@ type Config struct {
 	AttachStdin     bool
 	AttachStdout    bool
 	Cmd             []string
+	Healthcheck     *HealthConfig
 	Domainname      string
 	Entrypoint      []string
 	Env             []string