hub.extraEnv in dict format to support k8s EnvVar spec

jupyterhub · Aug 26, 2020 · 9d1ad08 · 9d1ad08
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commit 9d1ad08
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Showing 3 changed files with 46 additions and 12 deletions.
diff --git a/jupyterhub/schema.yaml b/jupyterhub/schema.yaml
@@ -308,20 +308,38 @@ properties:
         description: |
           Extra environment variables that should be set for the hub pod.
 
+          Environment variables are usually used to:
+            - Pass parameters to some custom code in `hub.extraConfig`.
+            - Configure code running in the hub pod, such as an authenticator or
+              spawner.
+
           ```yaml
           hub:
             extraEnv:
-              MY_ENV_VARS_NAME: "my env vars value"
+              # short notation, only for hardcoded string values
+              MY_ENV_VARS_NAME1: "my env var value 1"
+
+              # long notation, Kubernetes native syntax
+              dummyKey1:
+                name: HUB_NAMESPACE
+                valueFrom:
+                  fieldRef:
+                    fieldPath: metadata.namespace
+              dummyKey2:
+                name: PREFIXED_HUB_NAMESPACE
+                value: "my-prefix-$(HUB_NAMESPACE)"
+              dummyKey3:
+                name: SECRET_VALUE
+                valueFrom:
+                  secretKeyRef:
+                    name: my-k8s-secret
+                    key: password
           ```
 
-          **NOTE**: We still support this field being a list of
-          [EnvVar](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#envvar-v1-core)
-          objects as well.
-
-          These are usually used in two circumstances:
-            - Passing parameters to some custom code specified with `extraConfig`
-            - Passing parameters to an authenticator or spawner that can be directly customized
-              by environment variables (rarer)
+          In the long notation, you can provide any [Kubernetes
+          EnvVar](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#envvar-v1-core)
+          specification, and the name of the key (`dummyKey1`) will have no
+          impact.
       extraConfig:
         type: object
         description: |

diff --git a/jupyterhub/templates/hub/deployment.yaml b/jupyterhub/templates/hub/deployment.yaml
@@ -207,14 +207,25 @@ spec:
             {{- end }}
             {{- if .Values.hub.extraEnv }}
             {{- $extraEnvType := typeOf .Values.hub.extraEnv }}
-            {{- /* If we have a list, embed that here directly. This allows for complex configuration from configmap, downward API, etc. */}}
+            {{- /* If hub.extraEnv is a list, we inject it as it is. */}}
             {{- if eq $extraEnvType "[]interface {}" }}
             {{- .Values.hub.extraEnv | toYaml | trimSuffix "\n" | nindent 12 }}
+            {{- /* If hub.extraEnv is a map, we differentiate two cases:
+              - If hub.extraEnv.someKey has a map value, then we add the value
+                as a list element and ignore the key.
+              - If hub.extraEnv.someKey has a string value, then we use the
+                key as the environment variable name for the value.
+            */}}
             {{- else if eq $extraEnvType "map[string]interface {}" }}
-            {{- /* If we have a map, treat those as key-value pairs. */}}
             {{- range $key, $value := .Values.hub.extraEnv }}
+            {{- if eq (typeOf $value) "map[string]interface {}" }}
+            {{- $value | list | toYaml | nindent 12 }}
+            {{- else if eq (typeOf $value) "string" }}
             - name: {{ $key | quote }}
               value: {{ $value | quote }}
+            {{- else }}
+            {{ printf "hub.extraEnv.%s had an unexpected type (%s)" $key (typeOf $value) | fail }}
+            {{- end }}
             {{- end }}
             {{- end }}
             {{- end }}

diff --git a/tools/templates/lint-and-validate-values.yaml b/tools/templates/lint-and-validate-values.yaml
@@ -40,7 +40,12 @@ hub:
   extraConfigMap:
     mock.entry: mock-config-map-entry
   extraEnv:
-    MOCK_HUB_ENV: mock
+    dummyMergeKey1:
+      name: MOCK_ENV_VAR_NAME1
+      value: MOCK_ENV_VAR_VALUE1
+    dummyMergeKey2:
+      name: MOCK_ENV_VAR_NAME2
+      value: MOCK_ENV_VAR_VALUE2
   extraContainers: []
   extraVolumes: []
   extraVolumeMounts: []