Replicate most of drone-helm's config

internal/helm/config.go

@@ -0,0 +1,58 @@
+package helm
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Config struct {
+	// Configuration for drone-helm itself
+	Command            HelmCommand `envconfig:"HELM_COMMAND"`      // Helm command to run
+	DroneEvent         string      `envconfig:"DRONE_BUILD_EVENT"` // Drone event that invoked this plugin.
+	UpdateDependencies bool        `split_words:"true"`            // call `helm dependency update` before the main command
+	Repos              []string    `envconfig:"HELM_REPOS"`        // call `helm repo add` before the main command
+	Prefix             string      ``                              // Prefix to use when looking up secret env vars
+
+	// Global helm config
+	Debug          bool     ``                                                // global helm flag (also applies to drone-helm itself)
+	KubeConfig     string   `split_words:"true" default:"/root/.kube/config"` // path to the kube config file
+	Values         string   ``
+	StringValues   string   `split_words:"true"`
+	ValuesFiles    []string `split_words:"true"`
+	Namespace      string   ``
+	Token          string   `envconfig:"KUBERNETES_TOKEN"`
+	SkipTLSVerify  bool     `envconfig:"SKIP_TLS_VERIFY"`
+	Certificate    string   `envconfig:"KUBERNETES_CERTIFICATE"`
+	APIServer      string   `envconfig:"API_SERVER"`
+	ServiceAccount string   `envconfig:"SERVICE_ACCOUNT"` // Can't just use split_words; need envconfig to find the non-prefixed form
+
+	// Config specifically for `helm upgrade`
+	ChartVersion string `split_words:"true"` //
+	DryRun       bool   `split_words:"true"` // also available for `delete`
+	Wait         bool   ``                   //
+	ReuseValues  bool   `split_words:"true"` //
+	Timeout      string ``                   //
+	Chart        string ``                   // Also available for `lint`, in which case it must be a path to a chart directory
+	Release      string ``
+	Force        bool   `` //
+}
+
+type HelmCommand string
+
+// HelmCommand.Decode checks the given value against the list of known commands and generates a helpful error if the command is unknown.
+func (cmd *HelmCommand) Decode(value string) error {
+	known := []string{"upgrade", "delete", "lint", "help"}
+	for _, c := range known {
+		if value == c {
+			*cmd = HelmCommand(value)
+			return nil
+		}
+	}
+
+	if value == "" {
+		return nil
+	}
+	known[len(known)-1] = fmt.Sprintf("or %s", known[len(known)-1])
+	return fmt.Errorf("Unknown command '%s'. If specified, command must be %s.",
+		value, strings.Join(known, ", "))
+}