Merge pull request kubernetes#5108 from usabilla/set-values

Adds ability to set template context values on command line

cmd/kops/BUILD.bazel

@@ -114,6 +114,7 @@ go_library(
         "//vendor/k8s.io/client-go/kubernetes:go_default_library",
         "//vendor/k8s.io/client-go/tools/clientcmd:go_default_library",
         "//vendor/k8s.io/client-go/util/homedir:go_default_library",
+        "//vendor/k8s.io/helm/pkg/strvals:go_default_library",
         "//vendor/k8s.io/kubernetes/pkg/kubectl/cmd/templates:go_default_library",
         "//vendor/k8s.io/kubernetes/pkg/kubectl/cmd/util:go_default_library",
         "//vendor/k8s.io/kubernetes/pkg/kubectl/cmd/util/editor:go_default_library",

cmd/kops/toolbox_template.go

@@ -27,6 +27,7 @@ import (
 
 	"github.com/ghodss/yaml"
 	"github.com/spf13/cobra"
+	"k8s.io/helm/pkg/strvals"
 	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
 	"k8s.io/kubernetes/pkg/kubectl/util/i18n"
 
@@ -45,6 +46,7 @@ var (
 
 	kops toolbox template \
 		--values values.yaml --values=another.yaml \
+		--set var=value --set-string othervar=true \
 		--snippets file_or_directory --snippets=another.dir \
 		--template file_or_directory --template=directory  \
 		--output cluster.yaml
@@ -63,6 +65,8 @@ type toolboxTemplateOption struct {
 	outputPath    string
 	snippetsPath  []string
 	templatePath  []string
+	values        []string
+	stringValues  []string
 }
 
 // NewCmdToolboxTemplate returns a new templating command
@@ -87,6 +91,8 @@ func NewCmdToolboxTemplate(f *util.Factory, out io.Writer) *cobra.Command {
 	}
 
 	cmd.Flags().StringSliceVar(&options.configPath, "values", options.configPath, "Path to a configuration file containing values to include in template")
+	cmd.Flags().StringArrayVar(&options.values, "set", options.values, "Set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
+	cmd.Flags().StringArrayVar(&options.stringValues, "set-string", options.stringValues, "Set STRING values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
 	cmd.Flags().StringSliceVar(&options.templatePath, "template", options.templatePath, "Path to template file or directory of templates to render")
 	cmd.Flags().StringSliceVar(&options.snippetsPath, "snippets", options.snippetsPath, "Path to directory containing snippets used for templating")
 	cmd.Flags().StringVar(&options.outputPath, "output", options.outputPath, "Path to output file, otherwise defaults to stdout")
@@ -100,7 +106,7 @@ func NewCmdToolboxTemplate(f *util.Factory, out io.Writer) *cobra.Command {
 // runToolBoxTemplate is the action for the command
 func runToolBoxTemplate(f *util.Factory, out io.Writer, options *toolboxTemplateOption) error {
 	// @step: read in the configuration if any
-	context, err := newTemplateContext(options.configPath)
+	context, err := newTemplateContext(options.configPath, options.values, options.stringValues)
 	if err != nil {
 		return err
 	}
@@ -204,7 +210,7 @@ func runToolBoxTemplate(f *util.Factory, out io.Writer, options *toolboxTemplate
 }
 
 // newTemplateContext is responsible for loadding the --values and build a context for the template
-func newTemplateContext(files []string) (map[string]interface{}, error) {
+func newTemplateContext(files []string, values []string, stringValues []string) (map[string]interface{}, error) {
 	context := make(map[string]interface{}, 0)
 
 	for _, x := range files {
@@ -227,6 +233,20 @@ func newTemplateContext(files []string) (map[string]interface{}, error) {
 		}
 	}
 
+	// User specified a value via --set
+	for _, value := range values {
+		if err := strvals.ParseInto(value, context); err != nil {
+			return nil, fmt.Errorf("failed parsing --set data: %s", err)
+		}
+	}
+
+	// User specified a value via --set-string
+	for _, value := range stringValues {
+		if err := strvals.ParseIntoString(value, context); err != nil {
+			return nil, fmt.Errorf("failed parsing --set-string data: %s", err)
+		}
+	}
+
 	return context, nil
 }
 

docs/cli/kops_toolbox_template.md

@@ -20,6 +20,7 @@ kops toolbox template [flags]
   
   kops toolbox template \
   --values values.yaml --values=another.yaml \
+  --set var=value --set-string othervar=true \
   --snippets file_or_directory --snippets=another.dir \
   --template file_or_directory --template=directory  \
   --output cluster.yaml
@@ -28,14 +29,16 @@ kops toolbox template [flags]
 ### Options
 
 ```
-      --config-value string   Show the value of a specific configuration value
-      --fail-on-missing       Fail on referencing unset variables in templates (default true)
-      --format-yaml           Attempt to format the generated yaml content before output
-  -h, --help                  help for template
-      --output string         Path to output file, otherwise defaults to stdout
-      --snippets strings      Path to directory containing snippets used for templating
-      --template strings      Path to template file or directory of templates to render
-      --values strings        Path to a configuration file containing values to include in template
+      --config-value string      Show the value of a specific configuration value
+      --fail-on-missing          Fail on referencing unset variables in templates (default true)
+      --format-yaml              Attempt to format the generated yaml content before output
+  -h, --help                     help for template
+      --output string            Path to output file, otherwise defaults to stdout
+      --set stringArray          Set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)
+      --set-string stringArray   Set STRING values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)
+      --snippets strings         Path to directory containing snippets used for templating
+      --template strings         Path to template file or directory of templates to render
+      --values strings           Path to a configuration file containing values to include in template
 ```
 
 ### Options inherited from parent commands

docs/cluster_template.md

@@ -41,6 +41,42 @@ dnsZone: k8s.example.com
 awsRegion: eu-west-1
 ```
 
+When multiple environment files are passed using `--values` Kops performs a deep merge, for example given the following two files:
+```yaml
+# File values-a.yaml
+instanceGroups:
+  foo:
+    ami: ami-1234567
+    type: m4.large
+
+# File values-b.yaml
+instanceGroups:
+  foo:
+    type: t2.large
+```
+
+Would result in the `instanceGroups.foo` object having two properties: `{"ami": "ami-1234567", "type": "t2.large"}`.
+
+Besides specifying values through an environment file it is also possible to pass variables directly on the command line using the `--set` and `--set-string` command line options. The difference between the two options is that `--set-string` will always yield a string value while `--set` will cause the value to be parsed as a YAML value, for example the value `true` would turn into a boolean with `--set` while with `--set-string` it will be the literal string `"true"`. The format for specifying a variable is as follows:
+
+```shell
+kops toolbox template --template mytemplate.tpl --set 'version=1.0,foo.bar=baz' --set-string 'foo.myArray={1,2,3}' --set 'foo.myArray[1]=false,foo.myArray[3]=4'
+```
+
+which would yield the same values as using the `--values` option with the following file
+
+```yaml
+version: 1.0
+foo:
+  bar: baz
+  myArray:
+  - "1"
+  - false
+  - "3"
+  - 4
+```
+
+
 Running `kops toolbox template` replaces the placeholders in the template by values and generates the file output.yaml, which can then be used to replace the desired cluster configuration with `kops replace -f cluster.yaml`.
 
 Note: when creating a cluster desired configuration template, you can