api/types/container: define HealthStatus "pseudo" type

It currently is an alias for string, but may become a distinct type in future.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

api/types/container/health.go

@@ -2,17 +2,22 @@ package container
 
 import "time"
 
+// HealthStatus is a string representation of the container's health.
+//
+// It currently is an alias for string, but may become a distinct type in future.
+type HealthStatus = string
+
 // Health states
 const (
-	NoHealthcheck = "none"      // Indicates there is no healthcheck
-	Starting      = "starting"  // Starting indicates that the container is not yet ready
-	Healthy       = "healthy"   // Healthy indicates that the container is running correctly
-	Unhealthy     = "unhealthy" // Unhealthy indicates that the container has a problem
+	NoHealthcheck HealthStatus = "none"      // Indicates there is no healthcheck
+	Starting      HealthStatus = "starting"  // Starting indicates that the container is not yet ready
+	Healthy       HealthStatus = "healthy"   // Healthy indicates that the container is running correctly
+	Unhealthy     HealthStatus = "unhealthy" // Unhealthy indicates that the container has a problem
 )
 
 // Health stores information about the container's healthcheck results
 type Health struct {
-	Status        string               // Status is one of [Starting], [Healthy] or [Unhealthy].
+	Status        HealthStatus         // Status is one of [Starting], [Healthy] or [Unhealthy].
 	FailingStreak int                  // FailingStreak is the number of consecutive failures
 	Log           []*HealthcheckResult // Log contains the last few results (oldest first)
 }

container/health.go

@@ -30,7 +30,7 @@ func (s *Health) String() string {
 // Status returns the current health status.
 //
 // Note that this takes a lock and the value may change after being read.
-func (s *Health) Status() string {
+func (s *Health) Status() container.HealthStatus {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -46,7 +46,7 @@ func (s *Health) Status() string {
 // obeying the locking semantics.
 //
 // Status may be set directly if another lock is used.
-func (s *Health) SetStatus(new string) {
+func (s *Health) SetStatus(new container.HealthStatus) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 

container/state.go

@@ -112,12 +112,15 @@ func (s *State) String() string {
 	return fmt.Sprintf("Exited (%d) %s ago", s.ExitCodeValue, units.HumanDuration(time.Now().UTC().Sub(s.FinishedAt)))
 }
 
-// IsValidHealthString checks if the provided string is a valid container health status or not.
-func IsValidHealthString(s string) bool {
-	return s == container.Starting ||
-		s == container.Healthy ||
-		s == container.Unhealthy ||
-		s == container.NoHealthcheck
+// IsValidHealthString checks if the provided string is a valid
+// [container.HealthStatus].
+func IsValidHealthString(s container.HealthStatus) bool {
+	switch s {
+	case container.NoHealthcheck, container.Starting, container.Healthy, container.Unhealthy:
+		return true
+	default:
+		return false
+	}
 }
 
 // StateString returns a single string to describe state

container/state_test.go

@@ -10,22 +10,24 @@ import (
 )
 
 func TestIsValidHealthString(t *testing.T) {
-	contexts := []struct {
-		Health   string
-		Expected bool
+	tests := []struct {
+		health   container.HealthStatus
+		expected bool
 	}{
-		{container.Healthy, true},
-		{container.Unhealthy, true},
-		{container.Starting, true},
-		{container.NoHealthcheck, true},
-		{"fail", false},
+		{health: container.Healthy, expected: true},
+		{health: container.Unhealthy, expected: true},
+		{health: container.Starting, expected: true},
+		{health: container.NoHealthcheck, expected: true},
+		{health: "fail", expected: false},
 	}
 
-	for _, c := range contexts {
-		v := IsValidHealthString(c.Health)
-		if v != c.Expected {
-			t.Fatalf("Expected %t, but got %t", c.Expected, v)
-		}
+	for _, tc := range tests {
+		t.Run(tc.health, func(t *testing.T) {
+			v := IsValidHealthString(tc.health)
+			if v != tc.expected {
+				t.Fatalf("Expected %t, but got %t", tc.expected, v)
+			}
+		})
 	}
 }
 

integration/container/health_test.go

@@ -188,7 +188,7 @@ func pollForHealthCheckLog(ctx context.Context, client client.APIClient, contain
 	}
 }
 
-func pollForHealthStatus(ctx context.Context, client client.APIClient, containerID string, healthStatus string) func(log poll.LogT) poll.Result {
+func pollForHealthStatus(ctx context.Context, client client.APIClient, containerID string, healthStatus containertypes.HealthStatus) func(log poll.LogT) poll.Result {
 	return func(log poll.LogT) poll.Result {
 		inspect, err := client.ContainerInspect(ctx, containerID)