Add support for default parameter groups (#3)

* add support for default parameter groups

* update deps

* bump Buffalo version

* fixup

Author: tenyo

Gopkg.lock

@@ -6,8 +6,17 @@ This API provides simple restful API access to Amazon's RDS service.
 
 This API uses the standard format for input and output of parameters as defined by the AWS SDK (for reference see https://docs.aws.amazon.com/sdk-for-go/api/service/rds/).
 
+### Config
+
 You can define multiple _accounts_ in your `config.json` file which are mapped to endpoints by the API and allow RDS instances to be created in different AWS accounts. See [example config](config/config.example.json)
 
+In each account you can optionally define certain defaults that will be used if those parameters are not specified in the POST request when creating a database:
+  - `defaultSubnetGroup` - the subnet group that will be used if one is not given
+  - `defaultDBParameterGroupName` - map of ParameterGroupFamily to ParameterGroupName's
+  - `defaultDBClusterParameterGroupName` - map of ParameterGroupFamily to ClusterParameterGroupName's
+
+_Note that any default parameters need to refer to existing resources (groups), i.e. they need to be created separately outside of this API._
+
 ### Creating a database
 
 You can specify both database cluster and instance information in the POST to create just an instance or a cluster and a member instance. 

README.md

@@ -163,9 +163,27 @@ func DatabasesPost(c buffalo.Context) error {
 
 	// create rds cluster first, if specified
 	if input.Cluster != nil {
+		// set default subnet group
 		if input.Cluster.DBSubnetGroupName == nil {
 			input.Cluster.DBSubnetGroupName = aws.String(rdsClient.DefaultSubnetGroup)
 		}
+		// set default cluster parameter group
+		if input.Cluster.DBClusterParameterGroupName == nil {
+			pgFamily, pgErr := rdsClient.DetermineParameterGroupFamily(input.Cluster.Engine, input.Cluster.EngineVersion)
+			if pgErr != nil {
+				log.Println(pgErr.Error())
+				return c.Error(400, pgErr)
+			}
+			log.Println("Determined ParameterGroupFamily based on Engine:", pgFamily)
+			cPg, ok := rdsClient.DefaultDBClusterParameterGroupName[pgFamily]
+			if !ok {
+				log.Println("No matching DefaultDBClusterParameterGroupName found in config, using AWS default PG")
+			} else {
+				log.Println("Using DefaultDBClusterParameterGroupName:", cPg)
+				input.Cluster.DBClusterParameterGroupName = aws.String(cPg)
+			}
+		}
+
 		if clusterOutput, err = rdsClient.Service.CreateDBClusterWithContext(c, input.Cluster); err != nil {
 			log.Println(err.Error())
 			if aerr, ok := err.(awserr.Error); ok {
@@ -177,9 +195,27 @@ func DatabasesPost(c buffalo.Context) error {
 	}
 
 	// create rds instance
+	// set default subnet group
 	if input.Instance.DBSubnetGroupName == nil {
 		input.Instance.DBSubnetGroupName = aws.String(rdsClient.DefaultSubnetGroup)
 	}
+	// set default parameter group
+	if input.Instance.DBParameterGroupName == nil {
+		pgFamily, pgErr := rdsClient.DetermineParameterGroupFamily(input.Instance.Engine, input.Instance.EngineVersion)
+		if pgErr != nil {
+			log.Println(pgErr.Error())
+			return c.Error(400, pgErr)
+		}
+		log.Println("Determined ParameterGroupFamily based on Engine:", pgFamily)
+		pg, ok := rdsClient.DefaultDBParameterGroupName[pgFamily]
+		if !ok {
+			log.Println("No matching DefaultDBParameterGroupName found in config, using AWS default PG")
+		} else {
+			log.Println("Using DefaultDBParameterGroupName:", pg)
+			input.Instance.DBParameterGroupName = aws.String(pg)
+		}
+	}
+
 	if instanceOutput, err = rdsClient.Service.CreateDBInstanceWithContext(c, input.Instance); err != nil {
 		log.Println(err.Error())
 		if input.Cluster != nil {

actions/databases.go

@@ -10,7 +10,15 @@
       "region": "us-east-1",
       "akid": "AKID",
       "secret": "SECRET",
-      "defaultSubnetGroup": "default-subnets"
+      "defaultSubnetGroup": "default-subnets",
+      "defaultDBParameterGroupName": {
+        "postgres9.6": "my-postgres96",
+        "postgres10": "my-postgres10"
+      },
+      "defaultDBClusterParameterGroupName": {
+        "aurora5.6": "my-aurora56",
+        "aurora-mysql5.7": "my-aurora-mysql57"
+      }
     }
   },
   "token": "TOKEN"

config/config.example.json

@@ -1,6 +1,6 @@
 # This is a multi-stage Dockerfile and requires >= Docker 17.05
 # https://docs.docker.com/engine/userguide/eng-image/multistage-build/
-FROM gobuffalo/buffalo:v0.13.7 as builder
+FROM gobuffalo/buffalo:v0.13.13 as builder
 
 RUN mkdir -p $GOPATH/src/github.com/YaleSpinup/rds-api
 WORKDIR $GOPATH/src/github.com/YaleSpinup/rds-api

docker/Dockerfile

@@ -1,6 +1,6 @@
 # This is a multi-stage Dockerfile and requires >= Docker 17.05
 # https://docs.docker.com/engine/userguide/eng-image/multistage-build/
-FROM gobuffalo/buffalo:v0.13.7 as builder
+FROM gobuffalo/buffalo:v0.13.13 as builder
 
 RUN mkdir -p $GOPATH/src/github.com/YaleSpinup/rds-api
 WORKDIR $GOPATH/src/github.com/YaleSpinup/rds-api

docker/Dockerfile.local

@@ -18,10 +18,12 @@ type Config struct {
 
 // Account is the configuration for an individual account
 type Account struct {
-	Region             string
-	Akid               string
-	Secret             string
-	DefaultSubnetGroup string
+	Region                             string
+	Akid                               string
+	Secret                             string
+	DefaultSubnetGroup                 string
+	DefaultDBParameterGroupName        map[string]string
+	DefaultDBClusterParameterGroupName map[string]string
 }
 
 // LoadConfig loads the JSON configuration from the specified filename and returns a Config struct

pkg/common/config.go

@@ -13,8 +13,10 @@ import (
 
 // Client struct contains the initialized RDS service and other RDS-related parameters
 type Client struct {
-	Service            rdsiface.RDSAPI
-	DefaultSubnetGroup string
+	Service                            rdsiface.RDSAPI
+	DefaultSubnetGroup                 string
+	DefaultDBParameterGroupName        map[string]string
+	DefaultDBClusterParameterGroupName map[string]string
 }
 
 // NewSession creates an AWS session for RDS and returns an RDSClient
@@ -26,7 +28,9 @@ func NewSession(c common.Account) Client {
 	}))
 
 	return Client{
-		Service:            rds.New(sess),
-		DefaultSubnetGroup: c.DefaultSubnetGroup,
+		Service:                            rds.New(sess),
+		DefaultSubnetGroup:                 c.DefaultSubnetGroup,
+		DefaultDBParameterGroupName:        c.DefaultDBParameterGroupName,
+		DefaultDBClusterParameterGroupName: c.DefaultDBClusterParameterGroupName,
 	}
 }

pkg/rds/client.go

@@ -0,0 +1,27 @@
+package rds
+
+import (
+	"errors"
+
+	"github.com/aws/aws-sdk-go/service/rds"
+)
+
+// DetermineParameterGroupFamily returns the DBParameterGroupFamily based on the
+// given database Engine and EngineVersion
+// e.g. given engine "postgres" and engineVersion "10.5" it will return "postgres10"
+func (cl Client) DetermineParameterGroupFamily(engine, engineVersion *string) (string, error) {
+	input := &rds.DescribeDBEngineVersionsInput{
+		Engine:        engine,
+		EngineVersion: engineVersion,
+	}
+
+	evResult, err := cl.Service.DescribeDBEngineVersions(input)
+	if err != nil {
+		return "", err
+	}
+	if len(evResult.DBEngineVersions) == 0 {
+		return "", errors.New("Unable to find any matching database engine/version")
+	}
+
+	return *evResult.DBEngineVersions[0].DBParameterGroupFamily, nil
+}