Merge pull request kubernetes#168 from fraenkel/env-files

Initial --from-env-file proposal

kubectl-create-from-env-file.md

@@ -0,0 +1,84 @@
+# Kubectl create configmap/secret --env-file
+
+## Goals
+
+Allow a Docker environment file (.env) to populate an entire `ConfigMap` or `Secret`.
+The populated `ConfigMap` or  `Secret` can be referenced by a pod to load all
+the data contained within.
+
+## Design
+
+The `create configmap` subcommand would add a new option called
+`--from-env-file`. The option will accept a single file. The option may not be
+used in conjunction with `--from-file` or `--from-literal`.
+
+The `create secret generic` subcommand would add a new option called
+`--from-env-file`. The option will accept a single file. The option may not be
+used in conjunction with `--from-file` or `--from-literal`.
+
+### Environment file specification
+
+An environment file consists of lines to be in VAR=VAL format. Lines beginning
+with # (i.e. comments) are ignored, as are blank lines. Any whitespace in
+front of the VAR is removed. VAR must be a valid C_IDENTIFIER.  If the line
+consists of just VAR, then the VAL will be given a value from the current
+environment.
+
+Any ill-formed line will be flagged as an error and will prevent the
+`ConfigMap` or `Secret` from being created.
+
+[Docker's environment file processing](https://github.com/docker/docker/blob/master/runconfig/opts/envfile.go)
+
+## Examples
+
+```
+$ cat game.env
+enemies=aliens
+lives=3
+enemies_cheat=true
+enemies_cheat_level=noGoodRotten
+secret_code_passphrase=UUDDLRLRBABAS
+secret_code_allowed=true
+secret_code_lives=30
+```
+
+Create configmap from an env file:
+```
+kubectl create configmap game-config --from-env-file=./game.env
+```
+
+The populated configmap would look like:
+```
+$ kubectl get configmaps game-config -o yaml
+
+apiVersion: v1
+data:
+  enemies: aliens
+  lives: 3
+  enemies_cheat: true
+  enemies_cheat_level: noGoodRotten
+  secret_code_passphrase: UUDDLRLRBABAS
+  secret_code_allowed: true
+  secret_code_lives: 30
+```
+
+Create secret from an env file:
+```
+kubectl create secret generic game-config --from-env-file=./game.env
+```
+
+The populated secret would look like:
+```
+$ kubectl get secret game-config -o yaml
+
+apiVersion: v1
+type: Opaque
+data:
+  enemies: YWxpZW5z
+  enemies_cheat: dHJ1ZQ==
+  enemies_cheat_level: bm9Hb29kUm90dGVu
+  lives: Mw==
+  secret_code_allowed: dHJ1ZQ==
+  secret_code_lives: MzA=
+  secret_code_passphrase: VVVERExSTFJCQUJBUw==
+```