Allow specifying of Cloudformation template parameters (#123)

* Use correct type for body response

* Use correct type for statusCode

* Return 502 if status code is malformed

* Update Goformation to latest version

* Allow specifying of Cloudformation template parameters

invoke.go

@@ -12,6 +12,7 @@ import (
 	"sync"
 
 	"github.com/awslabs/goformation"
+	"github.com/awslabs/goformation/intrinsics"
 	"github.com/codegangsta/cli"
 )
 
@@ -33,7 +34,9 @@ func invoke(c *cli.Context) {
 	}
 
 	filename := getTemplateFilename(c.String("template"))
-	template, err := goformation.Open(filename)
+	template, err := goformation.OpenWithOptions(filename, &intrinsics.ProcessorOptions{
+		ParameterOverrides: parseParameters(c.String("parameter-values")),
+	})
 	if err != nil {
 		log.Fatalf("Failed to parse template: %s\n", err)
 	}

main.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
+	"strings"
 
 	"github.com/codegangsta/cli"
 	"github.com/fatih/color"
@@ -62,6 +64,11 @@ func main() {
 							Usage:  "AWS SAM template file",
 							EnvVar: "SAM_TEMPLATE_FILE",
 						},
+						cli.StringFlag{
+							Name:   "parameter-values",
+							Usage:  "Optional. A string that contains CloudFormation parameter overrides encoded as key-value pairs. Use the same format as the AWS CLI, e.g. 'ParameterKey=KeyPairName,ParameterValue=MyKey ParameterKey=InstanceType,ParameterValue=t1.micro'. In case of parsing errors all values are ignored",
+							EnvVar: "SAM_TEMPLATE_PARAM_ARG",
+						},
 						cli.StringFlag{
 							Name:  "log-file, l",
 							Usage: "Optional logfile to send runtime logs to",
@@ -124,6 +131,11 @@ func main() {
 							Usage:  "AWS SAM template file",
 							EnvVar: "SAM_TEMPLATE_FILE",
 						},
+						cli.StringFlag{
+							Name:   "parameter-values",
+							Usage:  "Optional. A string that contains CloudFormation parameter overrides encoded as key-value pairs. Use the same format as the AWS CLI, e.g. 'ParameterKey=KeyPairName,ParameterValue=MyKey ParameterKey=InstanceType,ParameterValue=t1.micro'. In case of parsing errors all values are ignored",
+							EnvVar: "SAM_TEMPLATE_PARAM_ARG",
+						},
 						cli.StringFlag{
 							Name:  "log-file, l",
 							Usage: "Optional. Logfile to send runtime logs to",
@@ -351,6 +363,24 @@ func main() {
 
 }
 
+// regexp that parses Cloudformation paramter key-value pair: https://regex101.com/r/hruxlg/3
+var paramRe = regexp.MustCompile(`(?:ParameterKey)=("(?:\\.|[^"\\]+)*"|(?:\\.|[^, "\\]+)*),(?:ParameterValue)=("(?:\\.|[^"\\]+)*"|(?:\\.|[^ ,"\\]+)*)`)
+
+// parseParameters parses the Cloudformation parameters like string and converts
+// it into a map of key-value pairs.
+func parseParameters(arg string) (overrides map[string]interface{}) {
+	overrides = make(map[string]interface{})
+
+	unquote := func(orig string) string {
+		return strings.Replace(strings.TrimSuffix(strings.TrimPrefix(orig, `"`), `"`), `\ `, ` `, -1)
+	}
+
+	for _, match := range paramRe.FindAllStringSubmatch(arg, -1) {
+		overrides[unquote(match[1])] = unquote(match[2])
+	}
+	return
+}
+
 // getTemplateFilename allows SAM Local to default to either template.yaml
 // or template.yml for the --template/-t parameter. This is helpful, as there
 // isn't a hard definition for the filename suffix and usage tends to be mixed

params_test.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Parse Cloudformation parameters", func() {
+
+	Context("with normal input", func() {
+
+		It("returns empty map when input is missing", func() {
+			p := parseParameters("")
+			Expect(p).To(BeEmpty())
+		})
+
+		It("returns expected values when input is correct", func() {
+			p := parseParameters("ParameterKey=KeyPairName,ParameterValue=MyKey ParameterKey=InstanceType,ParameterValue=t1.micro")
+			Expect(p).To(HaveLen(2))
+			Expect(p).To(HaveKeyWithValue("KeyPairName", "MyKey"))
+			Expect(p).To(HaveKeyWithValue("InstanceType", "t1.micro"))
+		})
+
+		It("returns partial values when input is malformed", func() {
+			p := parseParameters("ParameterKey=KeyPairName,ParameterValue=MyKey Para")
+			Expect(p).To(HaveLen(1))
+			Expect(p).To(HaveKeyWithValue("KeyPairName", "MyKey"))
+		})
+	})
+
+	Context("with escaped input", func() {
+
+		It("returns expected values when keys or values are quoted", func() {
+			p := parseParameters(`ParameterKey="KeyPairName",ParameterValue="MyKey " ParameterKey=InstanceType,ParameterValue=t1\ mic\ ro`)
+			Expect(p).To(HaveLen(2))
+			Expect(p).To(HaveKeyWithValue("KeyPairName", "MyKey "))
+			Expect(p).To(HaveKeyWithValue("InstanceType", "t1 mic ro"))
+		})
+
+		It("handles wrong quotings", func() {
+			p := parseParameters(`ParameterKey="KeyPairName,ParameterValue="MyKey" ParameterKey=InstanceType,ParameterValue=t1\ micro`)
+			Expect(p).To(HaveLen(1))
+			Expect(p).To(HaveKeyWithValue("InstanceType", "t1 micro"))
+		})
+
+	})
+})

start.go

@@ -8,6 +8,8 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/awslabs/goformation/intrinsics"
+
 	"github.com/awslabs/aws-sam-local/router"
 	"github.com/awslabs/goformation"
 	"github.com/codegangsta/cli"
@@ -29,7 +31,9 @@ func start(c *cli.Context) {
 	}
 
 	filename := getTemplateFilename(c.String("template"))
-	template, err := goformation.Open(filename)
+	template, err := goformation.OpenWithOptions(filename, &intrinsics.ProcessorOptions{
+		ParameterOverrides: parseParameters(c.String("parameter-values")),
+	})
 	if err != nil {
 		log.Fatalf("Failed to parse template: %s\n", err)
 	}