From 1263806a39d91de8eeda11c32012b198837c2c4d Mon Sep 17 00:00:00 2001
From: ben-toogood <bentoogood@gmail.com>
Date: Tue, 11 Aug 2020 08:38:30 +0100
Subject: [PATCH] util/kubernetes: add readiness check to deployments (#1923)

---
 util/kubernetes/client/client.go    |  7 +++++++
 util/kubernetes/client/templates.go | 16 +++++++++++++++-
 util/kubernetes/client/types.go     | 26 ++++++++++++++++++++------
 3 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/util/kubernetes/client/client.go b/util/kubernetes/client/client.go
index 910ec64d..7b14e08c 100644
--- a/util/kubernetes/client/client.go
+++ b/util/kubernetes/client/client.go
@@ -321,6 +321,13 @@ func NewDeployment(name, version, typ, namespace string) *Deployment {
 						Name:          "service-port",
 						ContainerPort: 8080,
 					}},
+					ReadinessProbe: &Probe{
+						TCPSocket: TCPSocketAction{
+							Port: 8080,
+						},
+						PeriodSeconds:       10,
+						InitialDelaySeconds: 10,
+					},
 				}},
 			},
 		},
diff --git a/util/kubernetes/client/templates.go b/util/kubernetes/client/templates.go
index 829d6415..61231119 100644
--- a/util/kubernetes/client/templates.go
+++ b/util/kubernetes/client/templates.go
@@ -92,8 +92,22 @@ spec:
             name: {{ .Name }}
           {{- end}}
           {{- end}}
+          {{- if .ReadinessProbe }}
+          {{- with .ReadinessProbe }}
+          readinessProbe:
+            {{- with .TCPSocket }}
+            tcpSocket:
+              {{- if .Host }}
+              host: {{ .Host }}
+              {{- end }}
+              port: {{ .Port }}
+            {{- end }}
+            initialDelaySeconds: {{ .InitialDelaySeconds }}
+            periodSeconds: {{ .PeriodSeconds }}
+          {{- end }}
+          {{- end }}
+      {{- end }}
       {{- end }}
-      {{- end}}
 `
 
 var serviceTmpl = `
diff --git a/util/kubernetes/client/types.go b/util/kubernetes/client/types.go
index cfc40235..41392733 100644
--- a/util/kubernetes/client/types.go
+++ b/util/kubernetes/client/types.go
@@ -35,12 +35,13 @@ type Condition struct {
 
 // Container defined container runtime values
 type Container struct {
-	Name    string          `json:"name"`
-	Image   string          `json:"image"`
-	Env     []EnvVar        `json:"env,omitempty"`
-	Command []string        `json:"command,omitempty"`
-	Args    []string        `json:"args,omitempty"`
-	Ports   []ContainerPort `json:"ports,omitempty"`
+	Name           string          `json:"name"`
+	Image          string          `json:"image"`
+	Env            []EnvVar        `json:"env,omitempty"`
+	Command        []string        `json:"command,omitempty"`
+	Args           []string        `json:"args,omitempty"`
+	Ports          []ContainerPort `json:"ports,omitempty"`
+	ReadinessProbe *Probe          `json:"readinessProbe,omitempty"`
 }
 
 // DeploymentSpec defines micro deployment spec
@@ -220,3 +221,16 @@ type ServiceAccount struct {
 	Metadata         *Metadata         `json:"metadata,omitempty"`
 	ImagePullSecrets []ImagePullSecret `json:"imagePullSecrets,omitempty"`
 }
+
+// Probe describes a health check to be performed against a container to determine whether it is alive or ready to receive traffic.
+type Probe struct {
+	TCPSocket           TCPSocketAction `json:"tcpSocket,omitempty"`
+	PeriodSeconds       int             `json:"periodSeconds"`
+	InitialDelaySeconds int             `json:"initialDelaySeconds"`
+}
+
+// TCPSocketAction describes an action based on opening a socket
+type TCPSocketAction struct {
+	Host string `json:"host,omitempty"`
+	Port int    `json:"port,omitempty"`
+}