From 257e0fc0a959f7e395e08136c92aabd63a5c3f31 Mon Sep 17 00:00:00 2001
From: Georg Kunz <kwd@gmx.ch>
Date: Mon, 30 Oct 2017 17:41:32 +0100
Subject: [PATCH] Allow custom Postgres pod environment variables

---
 README.md                 | 32 ++++++++++++++++++++++++++++++++
 pkg/cluster/k8sres.go     |  8 ++++++++
 pkg/util/config/config.go |  1 +
 3 files changed, 41 insertions(+)

diff --git a/README.md b/README.md
index eeea5e790..544f4d8a7 100644
--- a/README.md
+++ b/README.md
@@ -136,6 +136,38 @@ spec:
 
 Please be ware that the taint and toleration only ensures that no other pod gets scheduled to the "postgres" node but not that Postgres pods are placed on such a node. This can be achieved by setting a node affinity rule in the ConfigMap.
 
+#### Custom Pod Environment Variables
+
+It is possible to configure a config map which is used by the Postgres pods as an additional provider for environment variables.
+
+One use case is to customize the Spilo image and configure it with environment variables. The config map with the additional settings is configured in the operator's main config map:
+
+**postgres-operator ConfigMap**
+
+```
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: postgres-operator
+data:
+  # referencing config map with custom settings
+  pod_environment_configmap: postgres-pod-config
+  ...
+```
+
+**referenced ConfigMap `postgres-pod-config`**
+
+```
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: postgres-pod-config
+  namespace: default
+data:
+  MY_CUSTOM_VAR: value
+```
+
+This ConfigMap is then added as a source of environment variables to the Postgres StatefulSet/pods.
 
 # Setup development environment
 
diff --git a/pkg/cluster/k8sres.go b/pkg/cluster/k8sres.go
index d0337c64b..0ef31e26d 100644
--- a/pkg/cluster/k8sres.go
+++ b/pkg/cluster/k8sres.go
@@ -361,6 +361,13 @@ func (c *Cluster) generatePodTemplate(resourceRequirements *v1.ResourceRequireme
 	if cloneDescription.ClusterName != "" {
 		envVars = append(envVars, c.generateCloneEnvironment(cloneDescription)...)
 	}
+
+	envFromSource := []v1.EnvFromSource{}
+	if c.OpConfig.PodEnvironmentConfigMap != "" {
+		configMapRef := v1.ConfigMapEnvSource{LocalObjectReference: v1.LocalObjectReference{Name: c.OpConfig.PodEnvironmentConfigMap}}
+		envFromSource = append(envFromSource, v1.EnvFromSource{ConfigMapRef: &configMapRef})
+	}
+
 	privilegedMode := true
 	container := v1.Container{
 		Name:            c.containerName(),
@@ -388,6 +395,7 @@ func (c *Cluster) generatePodTemplate(resourceRequirements *v1.ResourceRequireme
 			},
 		},
 		Env: envVars,
+		EnvFrom: envFromSource,
 		SecurityContext: &v1.SecurityContext{
 			Privileged: &privilegedMode,
 		},
diff --git a/pkg/util/config/config.go b/pkg/util/config/config.go
index caf617aea..1e0af1324 100644
--- a/pkg/util/config/config.go
+++ b/pkg/util/config/config.go
@@ -31,6 +31,7 @@ type Resources struct {
 	DefaultCPULimit         string            `name:"default_cpu_limit" default:"3"`
 	DefaultMemoryLimit      string            `name:"default_memory_limit" default:"1Gi"`
 	EOLNodeLabel            map[string]string `name:"eol_node_label" default:"eol:true"`
+	PodEnvironmentConfigMap string            `name:"pod_environment_configmap" default:""`
 }
 
 // Auth describes authentication specific configuration parameters