Feat/cache dependencies s3 prefix (#2129)

* add prefix to s3-cache

Author: motatoes

action.yml

@@ -216,7 +216,11 @@ inputs:
     required: false
     default: 'false'
   cache-dependencies-s3-bucket:
-    description: "S3 bucket URL for caching (e.g., s3://mybucket/cache)"
+    description: "S3 bucket name for caching without the leading s3 (e.g. mybucket)"
+    required: false
+    default: ''
+  cache-dependencies-s3-bucket-prefix:
+    description: "S3 bucket prefix for caching (e.g. cache)"
     required: false
     default: ''
   cache-dependencies-s3-region:
@@ -332,8 +336,9 @@ runs:
     - name: restore-s3-cache
       shell: bash
       run: |
-        BUCKET=$(echo "${{ inputs.cache-dependencies-s3-bucket }}" | sed 's|^s3://||')
+        BUCKET="${{ inputs.cache-dependencies-s3-bucket }}"
         REGION="${{ inputs.cache-dependencies-s3-region }}"
+        PREFIX="${{ inputs.cache-dependencies-s3-bucket-prefix }}"
         
         SCRIPT_PATH="${{ github.action_path }}/scripts/s3-cache-download.bash"
         if [ ! -f "$SCRIPT_PATH" ]; then
@@ -343,7 +348,7 @@ runs:
         fi
         
         chmod +x "$SCRIPT_PATH"
-        "$SCRIPT_PATH" "$BUCKET" "$REGION" "$TF_PLUGIN_CACHE_DIR"
+        "$SCRIPT_PATH" "$BUCKET" "$PREFIX" "$REGION" "$TF_PLUGIN_CACHE_DIR"
       if: ${{ inputs.cache-dependencies-s3 == 'true' }}
 
     # Then terraform setup happens...
@@ -641,8 +646,9 @@ runs:
     - name: save-s3-cache
       shell: bash
       run: |
-        BUCKET=$(echo "${{ inputs.cache-dependencies-s3-bucket }}" | sed 's|^s3://||')
+        BUCKET="${{ inputs.cache-dependencies-s3-bucket }}"
         REGION="${{ inputs.cache-dependencies-s3-region }}"
+        PREFIX="${{ inputs.cache-dependencies-s3-bucket-prefix }}"
         
         SCRIPT_PATH="${{ github.action_path }}/scripts/s3-cache-upload.bash"
         if [ ! -f "$SCRIPT_PATH" ]; then
@@ -652,7 +658,7 @@ runs:
         fi
         
         chmod +x "$SCRIPT_PATH"
-        "$SCRIPT_PATH" "$BUCKET" "$REGION" "$TF_PLUGIN_CACHE_DIR"
+        "$SCRIPT_PATH" "$BUCKET" "$PREFIX" "$REGION" "$TF_PLUGIN_CACHE_DIR"
       if: ${{ always() && inputs.cache-dependencies-s3 == 'true' }}
 
 branding:

docs/ce/howto/caching-strategies.mdx

@@ -29,7 +29,8 @@ You can cache in AWS s3 rather than artefacts. This requires a bucket for cachin
     - uses: diggerhq/digger@vLatest
         with:
             cache-dependencies-s3: true
-            cache-dependencies-s3-bucket: s3://terraform-cache-1756322349465/cache
+            cache-dependencies-s3-bucket: terraform-cache-1756322349465
+            cache-dependencies-s3-bucket-prefix: cache
             cache-dependencies-s3-region: us-east-1
 ```
 

scripts/s3-cache-download.bash

@@ -5,8 +5,9 @@ set -e
 # Downloads terraform/terragrunt provider cache from S3
 
 BUCKET="$1"
-REGION="$2"
-CACHE_DIR="$3"
+PREFIX="$2"
+REGION="$3"
+CACHE_DIR="$4"
 
 # Validation
 if [ -z "$BUCKET" ]; then
@@ -29,8 +30,8 @@ mkdir -p "$CACHE_DIR"
 echo "Ensuring cache directory exists: $CACHE_DIR"
 
 # Download cache from S3
-echo "Restoring cache from S3 bucket: $BUCKET (region: $REGION)"
-if aws s3 sync "s3://$BUCKET" "$CACHE_DIR" --region "$REGION" --only-show-errors; then
+echo "Restoring cache from S3 bucket: $BUCKET (prefix: $PREFIX, region: $REGION)"
+if aws s3 sync "s3://$BUCKET/$PREFIX" "$CACHE_DIR" --region "$REGION"; then
   CACHED_FILES=$(find "$CACHE_DIR" -type f 2>/dev/null | wc -l)
   echo "Cache restored successfully ($CACHED_FILES files)"
 

scripts/s3-cache-upload.bash

@@ -5,15 +5,26 @@ set -e
 # Uploads terraform/terragrunt provider cache to S3
 
 BUCKET="$1"
-REGION="$2"
-CACHE_DIR="$3"
+PREFIX="$2"
+REGION="$3"
+CACHE_DIR="$4"
 
 # Validation
 if [ -z "$BUCKET" ]; then
   echo "Error: S3 bucket name is required"
   exit 1
 fi
 
+if [ -z "$PREFIX" ]; then
+  echo "Error: S3 bucket prefix is required"
+  exit 1
+fi
+
+if [[ "$PREFIX" == /* ]]; then
+  echo "Error: S3 bucket prefix should not start with a leading slash"
+  exit 1
+fi
+
 if [ -z "$REGION" ]; then
   echo "Error: AWS region is required"
   exit 1
@@ -53,10 +64,10 @@ if ! aws sts get-caller-identity --region "$REGION" &> /dev/null; then
 fi
 
 # Upload cache to S3
-echo "Saving cache to S3 bucket: $BUCKET (region: $REGION)"
+echo "Saving cache to S3 bucket: $BUCKET (prefix: $PREFIX, region: $REGION)"
 echo "Uploading $ARTIFACT_COUNT files"
 
-if aws s3 sync "$CACHE_DIR" "s3://$BUCKET" --region "$REGION" --only-show-errors; then
+if aws s3 sync "$CACHE_DIR" "s3://$BUCKET/$PREFIX" --region "$REGION"; then
   echo "Cache saved successfully"
 else
   echo "Warning: Failed to save cache (this won't fail the build)"