Merge pull request #10 from halprin/set-endpoint

Use Custom Endpoint

Author: halprin

README.md

@@ -12,12 +12,17 @@ _**Warning**: running this command will result in all the items in the specified
 is no "are you sure?" prompt._
 
 ```shell
-delete-dynamodb-items <table name>
+delete-dynamodb-items <table name> [--endpoint=URL]
 ```
 
 The program uses the default AWS credential algorithm to determine what IAM entity and region is used.  E.g. the
 `~/.aws/credentials` file, the `AWS_*` environment variables, etc.
 
+### Custom Endpoint
+
+You can customize the DynamoDB endpoint with the `--endpoint=` (or `-e`) option.  Set it to the URL of the endpoint.
+E.g. `--endpoint=http://localhost:8002`.  If unspecified, the default AWS endpoints are used.
+
 ## Build
 
 Run the following to compile your own copy from source.

cmd/main.go

@@ -1,34 +1,23 @@
 package main
 
 import (
-	"errors"
 	"github.com/halprin/delete-dynamodb-items/dynamo"
+	"github.com/halprin/delete-dynamodb-items/external/cli"
 	"log"
-	"os"
 )
 
 func main() {
 	log.Println("Start")
 
-	tableName, err := getTableName()
-	if err != nil {
-		killExecution(err)
-	}
+	cli.FillConfig()
 
-	err = dynamo.DeleteAllItemsInTable(tableName)
+	err := dynamo.DeleteAllItemsInTable()
 	if err != nil {
 		killExecution(err)
 	}
 	log.Println("Complete")
 }
 
-func getTableName() (string, error)  {
-	if len(os.Args) < 2 {
-		return "", errors.New("Provide a table name for the first argument")
-	}
-	return os.Args[1], nil
-}
-
 func killExecution(err error) {
 	log.Println("Failure")
 	log.Fatal(err.Error())

config/config.go

@@ -0,0 +1,20 @@
+package config
+
+var tableName *string
+var dynamoDbEndpoint *string
+
+func SetTableName(name string) {
+	tableName = &name
+}
+
+func GetTableName() *string {
+	return tableName
+}
+
+func SetDynamoDbEndpoint(endpoint string) {
+	dynamoDbEndpoint = &endpoint
+}
+
+func GetDynamoDbEndpoint() *string {
+	return dynamoDbEndpoint
+}

dynamo/dynamo.go

@@ -4,18 +4,27 @@ import (
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/dynamodb"
+	"github.com/halprin/delete-dynamodb-items/config"
 	"log"
 )
 
 var awsSession, sessionErr = session.NewSession()
 var dynamoService = dynamodb.New(awsSession)
 
-func DeleteAllItemsInTable(tableName string) error {
+func DeleteAllItemsInTable() error {
 	if sessionErr != nil {
 		log.Println("Initial AWS session failed")
 		return sessionErr
 	}
 
+	endpoint := config.GetDynamoDbEndpoint()
+	if endpoint != nil {
+		log.Printf("Using the custom endpoint %s", *endpoint)
+		dynamoService = dynamodb.New(awsSession, aws.NewConfig().WithEndpoint(*endpoint))
+	}
+
+	tableName := *config.GetTableName()
+
 	items, err := getItems(tableName)
 	if err != nil {
 		return err

external/cli/cli.go

@@ -0,0 +1,34 @@
+package cli
+
+import (
+	"github.com/halprin/delete-dynamodb-items/config"
+	"github.com/teris-io/cli"
+	"os"
+)
+
+func FillConfig() {
+	endpointKey := "endpoint"
+	tableNameCliArg := cli.NewArg("table name", "The name of the table for which all the items will be deleted").WithType(cli.TypeString)
+	endpointCliOption := cli.NewOption(endpointKey, "A URL of the DynamoDB endpoint to use").WithChar('e').WithType(cli.TypeString)
+
+	parser := cli.New("Deletes all the items in a DynamoDB table").WithArg(tableNameCliArg).WithOption(endpointCliOption)
+
+	invocation, arguments, options, err := parser.Parse(os.Args)
+	help, helpExistsInOptions := options["help"]
+
+	if err != nil {
+		_ = parser.Usage(invocation, os.Stdout)
+		os.Exit(1)
+	} else if helpExistsInOptions && help == "true" {
+		_ = parser.Usage(invocation, os.Stdout)
+		os.Exit(0)
+	}
+
+	tableName := arguments[0]
+	config.SetTableName(tableName)
+
+	endpoint, endpointExistsInOptions := options[endpointKey]
+	if endpointExistsInOptions {
+		config.SetDynamoDbEndpoint(endpoint)
+	}
+}

go.mod

@@ -2,4 +2,7 @@ module github.com/halprin/delete-dynamodb-items
 
 go 1.16
 
-require github.com/aws/aws-sdk-go v1.37.17
+require (
+	github.com/aws/aws-sdk-go v1.37.17
+	github.com/teris-io/cli v1.0.1
+)

go.sum

@@ -10,6 +10,8 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/teris-io/cli v1.0.1 h1:J6jnVHC552uqx7zT+Ux0++tIvLmJQULqxVhCid2u/Gk=
+github.com/teris-io/cli v1.0.1/go.mod h1:V9nVD5aZ873RU/tQXLSXO8FieVPQhQvuNohsdsKXsGw=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=