widespread improvements

Signed-off-by: Jason Hall <jason@chainguard.dev>

image-copy-ecr/README.md

@@ -9,3 +9,22 @@ The Terraform does everything:
 - sets up a Chainguard Identity with permissions to pull from the private cgr.dev repo
 - allows the Lambda function to assume the puller identity
 - sets up a subscription to notify the Lambda function when pushes happen to cgr.dev
+
+## Setup
+
+```sh
+aws sso login --profile my-profile
+chainctl auth login
+terraform init
+terraform apply
+```
+
+This will prompt for a group ID and destination repo, and show you the resources it will create.
+
+When the resources are created, any images that are pushed to your group will be mirrored to the ECR repository.
+
+The Lambda function has minimal permissions: it's only allowed to push images to the destination repo.
+
+The Chainguard identity also has minimal permissions: it only has permission to pull from the source repo.
+
+To tear down resources, run `terraform destroy`.

image-copy-ecr/cmd/app/generate.go

@@ -11,6 +11,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"net/http"
+	"net/url"
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
@@ -22,39 +23,40 @@ var timeNow = time.Now
 const (
 	audHeader = `Chainguard-Audience`
 	idHeader  = `Chainguard-Identity`
+
+	// hashInit is the sha256 hash of an empty buffer, hex encoded.
+	hashInit = `e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855`
+
+	// STS service details for signing
+	svc = `sts`
 )
 
 // generateToken creates token using the supplied AWS credentials that can prove the user's AWS identity. Audience and identity are
 // the Chainguard STS url (e.g https://issuer.enforce.dev) and the UID of the Chainguard assumable identity to assume via STS.
-func generateToken(ctx context.Context, creds aws.Credentials, audience, identity string) (string, error) {
-	req, err := http.NewRequest("POST", "https://sts.amazonaws.com", nil)
+func generateToken(ctx context.Context, creds aws.Credentials, region, audience, identity string) (string, error) {
+	url := (&url.URL{
+		Scheme: "https",
+		Host:   "sts.amazonaws.com",
+		Path:   "/",
+		RawQuery: url.Values{
+			"Action":  []string{"GetCallerIdentity"},
+			"Version": []string{"2011-06-15"},
+		}.Encode(),
+	}).String()
+	req, err := http.NewRequest("POST", url, nil)
 	if err != nil {
 		return "", fmt.Errorf("failed to create new HTTP request: %w", err)
 	}
-
-	req.URL.Path = "/"
-	req.URL.RawQuery = "Action=GetCallerIdentity&Version=2011-06-15"
 	req.Header.Add("Accept", "application/json")
 	req.Header.Add(audHeader, audience)
 	req.Header.Add(idHeader, identity)
 
-	const (
-		// hashInit is the sha256 hash of an empty buffer, hex encoded.
-		hashInit = `e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855`
-
-		// STS service details for signing
-		svc    = `sts`
-		region = `us-east-1`
-	)
-
-	err = v4.NewSigner().SignHTTP(ctx, creds, req, hashInit, svc, region, timeNow())
-	if err != nil {
+	if err := v4.NewSigner().SignHTTP(ctx, creds, req, hashInit, svc, region, timeNow()); err != nil {
 		return "", fmt.Errorf("failed to sign GetCallerIdentity request with AWS credentials: %w", err)
 	}
 
 	var b bytes.Buffer
-	err = req.Write(&b)
-	if err != nil {
+	if err := req.Write(&b); err != nil {
 		return "", fmt.Errorf("failed to serialize GetCallerIdentity HTTP request to buffer: %w", err)
 	}
 

image-copy-ecr/cmd/app/main.go

@@ -13,6 +13,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"net/url"
 	"path/filepath"
 	"strings"
 
@@ -30,6 +31,7 @@ type envConfig struct {
 	Issuer   string `envconfig:"ISSUER_URL" required:"true"`
 	Group    string `envconfig:"GROUP" required:"true"`
 	Identity string `envconfig:"IDENTITY" required:"true"`
+	Region   string `envconfig:"REGION" required:"true"`
 	Port     int    `envconfig:"PORT" default:"8080" required:"true"`
 	DstRepo  string `envconfig:"DST_REPO" required:"true"`
 }
@@ -96,7 +98,7 @@ func main() {
 		if err := crane.Copy(src, dst,
 			crane.WithAuthFromKeychain(authn.NewMultiKeychain(
 				amazonKeychain,
-				cgKeychain{env.Issuer, env.Identity},
+				cgKeychain{env.Issuer, env.Region, env.Identity},
 			))); err != nil {
 			return fmt.Errorf("copying image: %w", err)
 		}
@@ -118,7 +120,7 @@ func main() {
 }
 
 type cgKeychain struct {
-	issuer, identity string
+	issuer, region, identity string
 }
 
 func (k cgKeychain) Resolve(res authn.Resource) (authn.Authenticator, error) {
@@ -136,12 +138,20 @@ func (k cgKeychain) Resolve(res authn.Resource) (authn.Authenticator, error) {
 		return nil, fmt.Errorf("failed to retrieve credentials, %w", err)
 	}
 
-	awsTok, err := generateToken(ctx, creds, res.RegistryStr(), k.identity)
+	awsTok, err := generateToken(ctx, creds, k.region, res.RegistryStr(), k.identity)
 	if err != nil {
 		return nil, fmt.Errorf("generating AWS token: %w", err)
 	}
 
-	url := fmt.Sprintf("%s/sts/exchange?aud=%s&identity=%s", k.issuer, res.RegistryStr(), k.identity)
+	url := (&url.URL{
+		Scheme: "https",
+		Host:   k.issuer,
+		Path:   "/sts/exchange",
+		RawQuery: url.Values{
+			"aud":      []string{res.RegistryStr()},
+			"identity": []string{k.identity},
+		}.Encode(),
+	}).String()
 	req, err := http.NewRequest(http.MethodPost, url, nil)
 	if err != nil {
 		return nil, err

image-copy-ecr/iac/lambda.tf

@@ -38,10 +38,10 @@ locals {
   // Using a local for the lambda breaks a cyclic dependency between
   // chainguard_identity.aws and aws_lambda_function.lambda
   lambda_name = "chainguard-lambda"
-
-  repo_name = var.dst_repo == "" ? local.lambda_name : var.dst_repo
 }
 
+data "aws_region" "current" {}
+
 resource "aws_lambda_function" "lambda" {
   function_name = local.lambda_name
   role          = aws_iam_role.lambda.arn
@@ -55,6 +55,7 @@ resource "aws_lambda_function" "lambda" {
       IDENTITY   = chainguard_identity.aws.id
       ISSUER_URL = "https://issuer.enforce.dev"
       DST_REPO   = aws_ecr_repository.ecr_repo.repository_url
+      REGION     = data.aws_region.current.name
     }
   }
 }

image-copy-ecr/iac/outputs.tf

@@ -1,3 +1,7 @@
 output "url" {
   value = aws_lambda_function_url.lambda.function_url
 }
+
+output "dst_repo" {
+  value = aws_ecr_repository.ecr_repo.repository_url
+}

image-copy-ecr/iac/variables.tf

@@ -5,6 +5,5 @@ variable "group" {
 
 variable "dst_repo" {
   type        = string
-  default     = "image-copy-ecr/lambda"
   description = "The destination repo where images should be copied to."
 }

image-copy/README.md

@@ -9,3 +9,22 @@ The Terraform does everything:
 - sets up a Chainguard Identity with permissions to pull from the private cgr.dev repo
 - allows the Cloud Run service's SA to assume the puller identity
 - sets up a subscription to notify the Cloud Run service when pushes happen to cgr.dev
+
+# Setup
+
+```sh
+gcloud auth application-default login
+chainctl auth login
+terraform init
+terraform apply
+```
+
+This will prompt for a group ID and destination repo, and show you the resources it will create.
+
+When the resources are created, any images that are pushed to your group will be mirrored to the `gcr.io/<project-id>/<dst-repo>` repository.
+
+The Cloud Run service account has minimal permissions: it's only allowed to push images to the destination repo.
+
+The Chainguard identity also has minimal permissions: it only has permission to pull from the source repo.
+
+To tear down resources, run `terraform destroy`.

image-copy/iac/outputs.tf

@@ -1,3 +1,7 @@
 output "url" {
   value = google_cloud_run_service.image-copy.status[0].url
 }
+
+output "dst_repo" {
+  value = "${var.region}-docker.pkg.dev/${var.project}/${var.dst_repo}"
+}

image-workflow/README.md

@@ -34,7 +34,7 @@ Then `terraform apply` the module (e.g., from the root of this repo):
 
 ```
 module "image-workflow" {
-  source = "./image-workflow"  # TODO: move to enforce-events
+  source = "./image-workflow/iac"  # TODO: move to enforce-events
 
   # name is used to prefix resources created by this demo application
   # where possible.