Adding merging for helmDefaults args and --args, adding tillerNamspace and kubeContext to helmDefaults (#186)

Add tillerNamespace and kubeContext to helmDefaults. Also add merging of args capability. 

People can start adding additional fields under helmDefaults on top of this. The additional fields are merged to args as long as they are implemented using the framework introduced by this commit.

Changelog:

* adding merging for helm defaults args and --args, adding tillernamspace, kubecontext to helmdefaults, adding getargs to lint command

* adding docs for helmdefaults

* checking if empty default values

README.md

@@ -39,6 +39,17 @@ repositories:
 
 context: kube-context					 # kube-context (--kube-context)
 
+#default values to set for args along with dedicated keys that can be set by contributers, cli args take precedence overe these
+helmDefaults:           
+  tillerNamespace: tiller-namespace  #dedicated default key for tiller-namespace
+  kubeContext: kube-context          #dedicated default key for kube-context
+  args:
+    - "--wait"
+    - "--recreate-pods"
+    - "--timeout=600"
+    - "--force"
+    - "--reset-values"
+
 releases:
   # Published chart example
   - name: vault                            # name of this release

main.go

@@ -5,11 +5,10 @@ import (
 	"log"
 	"os"
 	"os/signal"
-	"strings"
-	"syscall"
-
 	"path/filepath"
 	"sort"
+	"strings"
+	"syscall"
 
 	"github.com/roboll/helmfile/helmexec"
 	"github.com/roboll/helmfile/state"
@@ -218,9 +217,9 @@ func main() {
 			},
 			Action: func(c *cli.Context) error {
 				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
-					args := c.String("args")
+					args := getArgs(c, state)
 					if len(args) > 0 {
-						helm.SetExtraArgs(strings.Split(args, " ")...)
+						helm.SetExtraArgs(args...)
 					}
 					if c.GlobalString("helm-binary") != "" {
 						helm.SetHelmBinary(c.GlobalString("helm-binary"))
@@ -518,9 +517,60 @@ func clean(state *state.HelmState, errs []error) error {
 
 func getArgs(c *cli.Context, state *state.HelmState) []string {
 	args := c.String("args")
+	argsMap := map[string]string{}
+
 	if len(args) > 0 {
-		state.HelmDefaults.Args = strings.Split(args, " ")
+		argsVals := strings.Split(args, " ")
+		for _, arg := range argsVals {
+			argVal := strings.SplitN(arg, "=", 2)
+			if len(argVal) > 1 {
+				arg := argVal[0]
+				value := argVal[1]
+				argsMap[arg] = value
+			} else {
+				arg := argVal[0]
+				argsMap[arg] = ""
+			}
+		}
 	}
+	if len(state.HelmDefaults.Args) > 0 {
+		for _, arg := range state.HelmDefaults.Args {
+			argVal := strings.SplitN(arg, "=", 2)
+			arg := argVal[0]
+			if _, exists := argsMap[arg]; !exists {
+				if len(argVal) > 1 {
+					argsMap[arg] = argVal[1]
+				} else {
+					argsMap[arg] = ""
+				}
+			}
+		}
+	}
+
+	if state.HelmDefaults.TillerNamespace != "" {
+		setDefaultValue(argsMap, "--tiller-namespace", state.HelmDefaults.TillerNamespace)
+	}
+	if state.HelmDefaults.KubeContext != "" {
+		setDefaultValue(argsMap, "--kube-context", state.HelmDefaults.KubeContext)
+	}
+
+	var argArr []string
+
+	for key, val := range argsMap {
+		if val != "" {
+			argArr = append(argArr, fmt.Sprintf("%s=%s", key, val))
+		} else {
+			argArr = append(argArr, fmt.Sprintf("%s", key))
+		}
+	}
+
+	state.HelmDefaults.Args = argArr
 
 	return state.HelmDefaults.Args
 }
+
+func setDefaultValue(argsMap map[string]string, flag string, value string) {
+	if _, exists := argsMap[flag]; !exists {
+		argsMap[flag] = value
+	}
+}

state/state.go

@@ -35,7 +35,9 @@ type HelmState struct {
 
 // HelmSpec to defines helmDefault values
 type HelmSpec struct {
-	Args []string `yaml:"args"`
+	KubeContext     string   `yaml:"kubeContext"`
+	TillerNamespace string   `yaml:"tillerNamespace"`
+	Args            []string `yaml:"args"`
 }
 
 // RepositorySpec that defines values for a helm repo