feat: load and interpolate variables from cloudformation output

cloudformation/cloudformation.go

@@ -0,0 +1,54 @@
+package cloudformation
+
+import (
+	"fmt"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/client"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/cloudformation"
+)
+
+var (
+	numberOfRetries = 10
+	throttleDelay   = client.DefaultRetryerMinRetryDelay
+)
+
+type Cloudformation struct {
+	client *cloudformation.CloudFormation
+}
+
+func (c *Cloudformation) GetOutput(stackname string) (map[string]string, error) {
+	result := map[string]string{}
+
+	resp, _ := c.client.DescribeStacks(&cloudformation.DescribeStacksInput{
+		StackName: aws.String(stackname),
+	})
+
+	if len(resp.Stacks) <= 0 {
+		return nil, fmt.Errorf("%s stack does not exist", stackname)
+	}
+
+	stack := resp.Stacks[0]
+
+	for _, output := range stack.Outputs {
+		result[*output.OutputKey] = *output.OutputValue
+	}
+
+	return result, nil
+}
+
+func NewCloudformation() Cloudformation {
+	cfSession := session.Must(session.NewSession())
+
+	retryer := client.DefaultRetryer{
+		NumMaxRetries:    numberOfRetries,
+		MinThrottleDelay: throttleDelay,
+	}
+
+	c := cloudformation.New(cfSession, &aws.Config{
+		Retryer: retryer,
+	})
+
+	return Cloudformation{client: c}
+}

cmd/deploy.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"log"
 
+	"github.com/adikari/safebox/v2/cloudformation"
+	conf "github.com/adikari/safebox/v2/config"
 	"github.com/adikari/safebox/v2/store"
 	"github.com/manifoldco/promptui"
 	"github.com/pkg/errors"
@@ -43,6 +45,24 @@ func deploy(cmd *cobra.Command, args []string) error {
 		return errors.Wrap(err, "failed to load config")
 	}
 
+	variables := map[string]string{
+		"stage":   stage,
+		"service": config.Service,
+	}
+
+	if len(config.Stacks) > 0 {
+		cf := cloudformation.NewCloudformation()
+		outputs, err := cf.GetOutput(config.Stacks[0])
+
+		if err != nil {
+			return errors.Wrap(err, "failed to load outputs")
+		}
+
+		for key, value := range outputs {
+			variables[key] = value
+		}
+	}
+
 	st, err := store.GetStore(config.Provider)
 
 	if err != nil {
@@ -92,21 +112,29 @@ func deploy(cmd *cobra.Command, args []string) error {
 	}
 
 	// filter configs with changed values
-	for _, c := range config.Configs {
+	for i, c := range config.Configs {
+		co := config.Configs[i]
+		v, err := conf.Interpolate(c.Value, variables)
+
+		if err != nil {
+			return errors.Wrap(err, "failed to interpolate template variables")
+		}
+
+		co.Value = v
 		found := false
 		for _, a := range all {
-			if c.Name == *a.Name {
+			if co.Name == *a.Name {
 				found = true
 
-				if c.Value != *a.Value {
-					configsToDeploy = append(configsToDeploy, c)
+				if co.Value != *a.Value {
+					configsToDeploy = append(configsToDeploy, co)
 				}
 				break
 			}
 		}
 
 		if !found {
-			configsToDeploy = append(configsToDeploy, c)
+			configsToDeploy = append(configsToDeploy, co)
 		}
 	}
 
@@ -129,8 +157,6 @@ func promptConfig(config store.ConfigInput) store.ConfigInput {
 		return nil
 	}
 
-	log.Printf("value %s", config.Value)
-
 	prompt := promptui.Prompt{
 		Label:    config.Key(),
 		Validate: validate,

config/config.go

@@ -14,8 +14,9 @@ type rawConfig struct {
 	Provider string
 	Service  string
 
-	Config map[string]map[string]string
-	Secret map[string]map[string]string
+	Config               map[string]map[string]string
+	Secret               map[string]map[string]string
+	CloudformationStacks []string `yaml:"cloudformation-stacks"`
 }
 
 type Config struct {
@@ -24,6 +25,7 @@ type Config struct {
 	All      []store.ConfigInput
 	Configs  []store.ConfigInput
 	Secrets  []store.ConfigInput
+	Stacks   []string
 }
 
 type LoadConfigInput struct {
@@ -58,37 +60,39 @@ func Load(param LoadConfigInput) (*Config, error) {
 		c.Provider = store.SsmProvider
 	}
 
-	parseConfig(rc, &c, param)
-
-	return &c, nil
-}
-
-func parseConfig(rc rawConfig, c *Config, param LoadConfigInput) {
 	variables := map[string]string{
 		"stage":   param.Stage,
 		"service": c.Service,
 	}
 
+	for _, name := range rc.CloudformationStacks {
+		value, err := Interpolate(name, variables)
+		if err != nil {
+			return nil, err
+		}
+		c.Stacks = append(c.Stacks, value)
+	}
+
 	for key, value := range rc.Config["defaults"] {
 		c.Configs = append(c.Configs, store.ConfigInput{
 			Name:   formatPath(param.Stage, c.Service, key),
-			Value:  interpolate(value, variables),
+			Value:  value,
 			Secret: false,
 		})
 	}
 
 	for key, value := range rc.Config["shared"] {
 		c.Configs = append(c.Configs, store.ConfigInput{
 			Name:   formatSharedPath(param.Stage, key),
-			Value:  interpolate(value, variables),
+			Value:  value,
 			Secret: false,
 		})
 	}
 
 	for key, value := range rc.Config[param.Stage] {
 		c.Configs = append(c.Configs, store.ConfigInput{
 			Name:   formatPath(param.Stage, c.Service, key),
-			Value:  interpolate(value, variables),
+			Value:  value,
 			Secret: false,
 		})
 	}
@@ -112,6 +116,8 @@ func parseConfig(rc rawConfig, c *Config, param LoadConfigInput) {
 	}
 
 	c.All = append(c.Secrets, c.Configs...)
+
+	return &c, nil
 }
 
 func formatSharedPath(stage string, key string) string {
@@ -122,12 +128,17 @@ func formatPath(stage string, service string, key string) string {
 	return fmt.Sprintf("/%s/%s/%s", stage, service, key)
 }
 
-func interpolate(value string, variables map[string]string) string {
+func Interpolate(value string, variables map[string]string) (string, error) {
 	var result bytes.Buffer
-	tmpl, _ := template.New("interpolate").Parse(value)
+	tmpl, _ := template.New("interpolate").Option("missingkey=error").Parse(value)
+
+	err := tmpl.Execute(&result, variables)
+
+	if err != nil {
+		return "", err
+	}
 
-	tmpl.Execute(&result, variables)
-	return result.String()
+	return result.String(), nil
 }
 
 func removeDuplicate(input []store.ConfigInput) []store.ConfigInput {

config/config_test.go

@@ -3,7 +3,7 @@ package config
 import "testing"
 
 func Test_LoadConfig_InvalidPath(t *testing.T) {
-	_, err := Load(LoadParam{Path: "invalid file"})
+	_, err := Load(LoadConfigInput{Path: "invalid file"})
 	expected := "missing safebox config file invalid file"
 
 	if err.Error() != expected {

example/safebox.yml

@@ -1,18 +1,21 @@
 service: safebox
 provider: ssm
 
+cloudformation-stacks:
+  - "{{.stage}}-shared-infra-SharedInfraServerless"
+
 config:
   defaults:
     DB_NAME: "database name updated"
-    API_ENDPOINT: "endpoint"
-    NEW: "endpoint"
+    API_ENDPOINT: "{{.authorizerLambaArns}}"
+    NEW: "endpoint-{{.stage}}"
     NEW2: "endpoint updated"
 
   prod:
     DB_NAME: "production db name"
 
   dev:
-    DB_NAME: "dev db name {{.stage}}"
+    DB_NAME: "dev db name"
 
   shared:
     SHARED_KEY: "shared key"