Fix method to read

Author: aleclerc-cio

README.md

@@ -33,8 +33,12 @@ go install github.com/richardartoul/gobuildcache@latest
 
 ## Usage
 
+You can configure `gobuildcache` by passing arguments directly to the program via `GOCACHEPROG`, or by using environment variables. The CLI argument approach is recommended for CI/CD workflows.
+
+### Using CLI Arguments (Recommended)
+
 ```bash
-export GOCACHEPROG=gobuildcache
+export GOCACHEPROG="gobuildcache --backend=disk"
 go build ./...
 go test ./...
 ```
@@ -43,61 +47,91 @@ By default, `gobuildcache` uses an on-disk cache stored in the OS default tempor
 
 For "production" use-cases in CI, you'll want to configure `gobuildcache` to use S3 Express One Zone, Google Cloud Storage, or a similarly low latency distributed backend.
 
+### Using Environment Variables (Alternative)
+
+You can also configure `gobuildcache` using environment variables:
+
+```bash
+export GOCACHEPROG=gobuildcache
+export BACKEND_TYPE=disk
+go build ./...
+go test ./...
+```
+
+**Note:** CLI arguments take precedence over environment variables when both are provided.
+
 ### Using S3
 
+**Using CLI arguments (recommended):**
+
 ```bash
-export BACKEND_TYPE=s3
-export S3_BUCKET=$BUCKET_NAME
+export GOCACHEPROG="gobuildcache --backend=s3 --s3-bucket=$BUCKET_NAME --s3-prefix=go-build-cache/"
+export AWS_REGION=$BUCKET_REGION
+export AWS_ACCESS_KEY_ID=$AWS_ACCESS_KEY
+export AWS_SECRET_ACCESS_KEY=$AWS_SECRET_ACCESS_KEY
+go build ./...
+go test ./...
 ```
 
-You'll also have to provide AWS credentials. `gobuildcache` embeds the AWS V2 S3 SDK so any method of providing credentials to that library will work, but the simplest is to use environment variables as demonstrated below.
+**Using environment variables:**
 
 ```bash
 export GOCACHEPROG=gobuildcache
 export BACKEND_TYPE=s3
 export S3_BUCKET=$BUCKET_NAME
+export S3_PREFIX=go-build-cache/
 export AWS_REGION=$BUCKET_REGION
 export AWS_ACCESS_KEY_ID=$AWS_ACCESS_KEY
 export AWS_SECRET_ACCESS_KEY=$AWS_SECRET_ACCESS_KEY
 go build ./...
 go test ./...
 ```
 
+You'll need to provide AWS credentials. `gobuildcache` embeds the AWS V2 S3 SDK so any method of providing credentials to that library will work (environment variables, IAM roles, etc.).
+
 ### Using Google Cloud Storage (GCS)
 
+**Using CLI arguments (recommended):**
+
+```bash
+export GOCACHEPROG="gobuildcache --backend=gcs --gcs-bucket=$BUCKET_NAME --gcs-prefix=go-build-cache/"
+go build ./...
+go test ./...
+```
+
+**Using environment variables:**
+
 ```bash
+export GOCACHEPROG=gobuildcache
 export BACKEND_TYPE=gcs
 export GCS_BUCKET=$BUCKET_NAME
+export GCS_PREFIX=go-build-cache/
+go build ./...
+go test ./...
 ```
 
 GCS authentication uses Application Default Credentials. You can provide credentials in one of the following ways:
 
 1. **Service Account JSON file** (recommended for CI):
 ```bash
 export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account-key.json
-export GOCACHEPROG=gobuildcache
-export BACKEND_TYPE=gcs
-export GCS_BUCKET=$BUCKET_NAME
+export GOCACHEPROG="gobuildcache --backend=gcs --gcs-bucket=$BUCKET_NAME"
 go build ./...
 go test ./...
 ```
 
 2. **Metadata service** (when running on GCP):
 ```bash
 # No credentials file needed - uses metadata service automatically
-export GOCACHEPROG=gobuildcache
-export BACKEND_TYPE=gcs
-export GCS_BUCKET=$BUCKET_NAME
+export GOCACHEPROG="gobuildcache --backend=gcs --gcs-bucket=$BUCKET_NAME"
 go build ./...
 go test ./...
 ```
 
 3. **gcloud CLI credentials** (for local development):
 ```bash
 gcloud auth application-default login
-export GOCACHEPROG=gobuildcache
-export BACKEND_TYPE=gcs
-export GCS_BUCKET=$BUCKET_NAME
+export GOCACHEPROG="gobuildcache --backend=gcs --gcs-bucket=$BUCKET_NAME"
 go build ./...
 go test ./...
 ```

examples/github_actions_gcs.yml

@@ -0,0 +1,32 @@
+name: Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
+
+jobs:
+  test:
+    name: Run Tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.25'
+          # Use our own cache, obviously.
+          cache: false
+      - name: Install gobuildcache
+        run: go install github.com/richardartoul/gobuildcache@latest
+      - name: Authenticate to Google Cloud
+        uses: google-github-actions/auth@v2
+        with:
+          credentials_json: ${{ secrets.GCP_SA_KEY }}
+      - name: Run short tests
+        env:
+          GOCACHEPROG: "gobuildcache --backend=gcs --gcs-bucket=${{ secrets.GCS_BUCKET }} --gcs-prefix=go-build-cache/${{ github.repository }}"
+        run: go test ./...

examples/github_actions_s3.yml

@@ -24,13 +24,10 @@ jobs:
         run: go install github.com/richardartoul/gobuildcache@latest
       - name: Run short tests
         env:
-          BACKEND_TYPE: s3
-          S3_BUCKET: EXAMPLE_BUCKET
-          S3_PREFIX: EXAMPLE_PREFIX
           AWS_REGION: EXAMPLE_REGION
           AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
           AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
-          GOCACHEPROG: gobuildcache
+          GOCACHEPROG: "gobuildcache --backend=s3 --s3-bucket=EXAMPLE_BUCKET --s3-prefix=EXAMPLE_PREFIX"
         run: go test ./...
 
 

examples/github_actions_tigris.yml

@@ -24,14 +24,10 @@ jobs:
         run: go install github.com/richardartoul/gobuildcache@latest
       - name: Run short tests
         env:
-          BACKEND_TYPE: s3
-          S3_BUCKET: EXAMPLE_BUCKET
-          S3_PREFIX: EXAMPLE_PREFIX
-          AWS_REGION: EXAMPLE_REGION
-          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
-          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
           AWS_ENDPOINT_URL_S3: https://t3.storage.dev
           AWS_ENDPOINT_URL_IAM: https://iam.storage.dev
           AWS_REGION: auto
-          GOCACHEPROG: gobuildcache
+          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+          GOCACHEPROG: "gobuildcache --backend=s3 --s3-bucket=EXAMPLE_BUCKET --s3-prefix=EXAMPLE_PREFIX"
         run: go test ./...

pkg/backends/gcs.go

@@ -28,9 +28,10 @@ type GCS struct {
 func NewGCS(bucket, prefix string) (*GCS, error) {
 	ctx := context.Background()
 
-	// Create GCS client using Application Default Credentials
-	// This will use GOOGLE_APPLICATION_CREDENTIALS env var or metadata service
-	client, err := storage.NewClient(ctx)
+	// Create GCS client using Application Default Credentials.
+	// WithJSONReads forces the JSON API for downloads (default is XML).
+	// This is required for GCS Anywhere Cache compatibility.
+	client, err := storage.NewClient(ctx, storage.WithJSONReads())
 	if err != nil {
 		return nil, fmt.Errorf("failed to create GCS client: %w", err)
 	}