Add Node.js as supported runtime

With this patch, lambda-layer-tool also supports building Lambda layer
for Node.js runtimes. It uses NPM to install the specified packages.

Author: jacksgt

.github/workflows/pythonapp.yml

@@ -30,9 +30,19 @@ jobs:
       run: |
         pip install -r dev-requirements.txt
         python3 -m mypy *.py
-    - name: Build example layer
+    - name: Build example Python layer
       run: |
         cd tests/numpy/
         ../../layer-tool.py --list
         ../../layer-tool.py --build awesome-numpy
         du -h awesome-numpy.zip
+    - name: Set up Node v10
+      uses: actions/setup-node@v1
+      with:
+        node-version: '10.x'
+    - name: Build example Node.js layer
+      run: |
+        cd tests/aws-sdk/
+        ../../layer-tool.py --list
+        ../../layer-tool.py --build awesome-aws-sdk
+        du -h awesome-aws-sdk.zip

README.md

@@ -8,7 +8,8 @@ Instead of manually copy & pasting build instructions for a Lambda Layer into yo
 Given a simple YAML file, it will:
 * create a new, clean directory for the lambda layer,
 * run specified pre-installation commands,
-* install python requirements with Pip in a virtual environment,
+* *Python*: install requirements with Pip in a virtual environment,
+* *Node.js*: install dependencies with NPM,
 * strip any binaries and libraries in the lambda directory,
 * apply global and layer-specific exclusion patterns,
 * bundle the remainder up into a ZIP archive.
@@ -66,6 +67,8 @@ $ ./layer-tool.py --publish awesome-numpy
 
 To learn how to use this tool to reduce the size of your layers, read the [post about creating a minimal boto3 layer](https://blog.cubieserver.de/2020/building-a-minimal-boto3-lambda-layer/).
 
+The [`tests` directory](./tests/) also serve as examples how to build layers for different runtimes (Python, Node.js).
+
 ## Lambda Environment
 
 To match the environment of AWS Lambda functions as closely as possible (especially when you use this tool on non-Linux systems), the tool should be run inside a Docker container.
@@ -92,8 +95,8 @@ In addition to the Python dependencies (`requirements.txt`), this tool currently
 
 ## Limitations
 
-Currently, this tool only supports building Python layers with Pip.
-However, it should be fairly straightforward to extend the functionality to other runtimes, e.g. JavaScript.
+Currently, this tool only supports building Python layers with Pip and Node.js layer with NPM.
+However, it should be fairly straightforward to extend the functionality to other runtimes and package managers.
 
 ## License
 

layer-tool.py

@@ -42,7 +42,7 @@ def main():
     if not file_version:
         print("Warning: no version specified in file!")
     elif file_version != '0.3':
-        print("Unsupport file version: ", file_version)
+        print("Unsupported file version: ", file_version)
         return 1
 
     # basic sanity check for YAML file structure
@@ -118,43 +118,82 @@ def build_layer(layername: str, options: Dict[str, Any]) -> int:
 
     # set_paths
     venv_dir: str = os.path.join(tmp_dir_path, "venv/")
+    node_modules_dir: str = os.path.join(tmp_dir_path, "node_modules/")
     pip_bin: str = os.path.join(venv_dir, "bin/pip")
-    lambda_dir: str = os.path.join(tmp_dir_path, "python/")
     outfile: str = layername + ".zip"
 
+    lambda_dir: str
+    if runtime.startswith("python"):
+        lambda_dir = os.path.join(tmp_dir_path, "python")
+    elif runtime.startswith("node"):
+        lambda_dir = os.path.join(tmp_dir_path, "nodejs")
+
     # create a new directory
     # which only contains files relevant to the lambda layer
     os.mkdir(lambda_dir)
 
-    # activate virtualenv
-    venv.create(venv_dir, with_pip=True)
+    if runtime.startswith('python'):
+        # activate virtualenv
+        venv.create(venv_dir, with_pip=True)
 
-    # run pre-install steps
-    for cmd in pre_install_cmds:
-        try:
-            subprocess.run(cmd, shell=True, check=True)
-        except subprocess.CalledProcessError as e:
-            print(e)
-            return 1
+        # run pre-install steps
+        for cmd in pre_install_cmds:
+            try:
+                subprocess.run(cmd, shell=True, check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
 
-    # install requirements with pip in venv
-    for r in requirements:
-        try:
-            subprocess.run([pip_bin, "install", r], check=True)
-        except subprocess.CalledProcessError as e:
-            print(e)
-            return 1
+        # install requirements with pip in venv
+        for r in requirements:
+            try:
+                subprocess.run([pip_bin, "install", r], check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
 
-    # save venv packages
-    with open(os.path.join(lambda_dir, 'pip-freeze.txt'), 'w') as outstream:
-        try:
-            subprocess.run([pip_bin, "freeze"], stdout=outstream, check=True)
-        except subprocess.CalledProcessError as e:
-            print(e)
-            return 1
+        # save venv packages
+        with open(os.path.join(lambda_dir, 'pip-freeze.txt'), 'w') as outstream:
+            try:
+                subprocess.run([pip_bin, "freeze"], stdout=outstream, check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
+
+        # move (copy) the installed requirements into the layer path
+        os.rename(os.path.join(venv_dir, "lib/"), os.path.join(lambda_dir, "lib/"))
+
+    elif runtime.startswith('node'):
+        # this ensures pre-install commands work properly
+        os.mkdir(node_modules_dir)
 
-    # move (copy) the installed requirements into the layer path
-    os.rename(os.path.join(venv_dir, "lib/"), os.path.join(lambda_dir, "lib/"))
+        # run pre-install steps
+        for cmd in pre_install_cmds:
+            try:
+                subprocess.run(cmd, shell=True, check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
+
+        # install packages with npm
+        for r in requirements:
+            try:
+                subprocess.run(["npm", "install", r], check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
+
+        # save installed packages
+        with open(os.path.join(lambda_dir, 'npm-list.txt'), 'w') as outstream:
+            try:
+                subprocess.run(["npm", "list"], stdout=outstream, check=True)
+            except subprocess.CalledProcessError as e:
+                print(e)
+                return 1
+
+        # move the installed dependencies into the layer path
+        os.rename(node_modules_dir, os.path.join(lambda_dir, "node_modules/"))
+        os.rename(os.path.join(tmp_dir_path, "package-lock.json"), os.path.join(lambda_dir, "package-lock.json"))
 
     # put current layer configuration into the folder
     with open(os.path.join(lambda_dir, 'layer.yaml'), 'w') as outstream:
@@ -169,7 +208,7 @@ def build_layer(layername: str, options: Dict[str, Any]) -> int:
         return 1
 
     # package to zip archive and exclude unnecessary files
-    zip_cmd: List[str] = ['zip', '-r', '-9', os.path.join(work_dir, outfile), "python/"]
+    zip_cmd: List[str] = ['zip', '--filesync', '-r', '-9', os.path.join(work_dir, outfile), os.path.basename(lambda_dir)]
     for exclude in excludes:
         zip_cmd.append('-x')
         zip_cmd.append(exclude)
@@ -193,7 +232,17 @@ def build_layer(layername: str, options: Dict[str, Any]) -> int:
 
 
 def check_runtime(expected_runtime: str) -> bool:
-    actual_runtime: str = "python{}.{}".format(sys.version_info[0], sys.version_info[1])
+    actual_runtime: str
+    if expected_runtime.startswith("python"):
+        actual_runtime = "python{}.{}".format(sys.version_info[0], sys.version_info[1])
+    elif expected_runtime.startswith("node"):
+        node_major_version: str = subprocess.check_output(["node", "--version"]).decode("ascii")
+        node_major_version = node_major_version[1:].split('.')[0]
+        actual_runtime = "node{}.x".format(node_major_version)
+    else:
+        print("Error: unsupported runtime {}".format(expected_runtime))
+        return False
+
     if actual_runtime != expected_runtime:
         print("Error: specified runtime {} does not match: {}".format(expected_runtime, actual_runtime))
         return False

tests/aws-sdk/layers.yaml

@@ -0,0 +1,19 @@
+---
+version: '0.3'
+default_excludes:
+  - 'LICENSE'
+  - 'CHANGELOG'
+  - 'README.md'
+  - '.npmignore'
+
+layers:
+  awesome-aws-sdk:
+    description: 'AWS SDK JS 2.668'
+    runtimes: 'node10.x'
+    pre_installs:
+      - 'echo "Hello, World!" > node_modules/hello-world.txt'
+    requirements:
+      - 'aws-sdk@2.668.0'
+    excludes:
+      - '*/aws-sdk/*.d.ts'
+      - '*/aws-sdk/*.txt'