fix: Checks for npm instead of runtime when building nodejs packages (#364)

Co-authored-by: Anton Babenko <anton@antonbabenko.com>

Author: lorengordon

examples/build-package/main.tf

@@ -219,8 +219,8 @@ module "package_with_docker" {
   docker_pip_cache      = true
   docker_with_ssh_agent = true
   #  docker_file           = "${path.module}/../fixtures/python3.8-app1/docker/Dockerfile"
-  docker_build_root = "${path.module}/../../docker"
-  docker_image      = "public.ecr.aws/sam/build-python3.8"
+  docker_build_root = "${path.module}/../fixtures/python3.8-app1/docker"
+  docker_image      = "public.ecr.aws/sam/build-python3.8:latest"
 }
 
 # Create zip-archive of a single directory where "npm install" will also be executed (default for nodejs runtime)
@@ -278,7 +278,7 @@ module "lambda_layer" {
 
   build_in_docker = true
   runtime         = "python3.8"
-  docker_image    = "public.ecr.aws/sam/build-python3.8"
+  docker_image    = "public.ecr.aws/sam/build-python3.8:latest"
   docker_file     = "${path.module}/../fixtures/python3.8-app1/docker/Dockerfile"
 }
 

package.py

@@ -649,6 +649,7 @@ def plan(self, source_path, query):
         hash = source_paths.append
 
         def pip_requirements_step(path, prefix=None, required=False, tmp_dir=None):
+            command = runtime
             requirements = path
             if os.path.isdir(path):
                 requirements = os.path.join(path, 'requirements.txt')
@@ -657,16 +658,17 @@ def pip_requirements_step(path, prefix=None, required=False, tmp_dir=None):
                     raise RuntimeError(
                         'File not found: {}'.format(requirements))
             else:
-                if not query.docker and not shutil.which(runtime):
+                if not query.docker and not shutil.which(command):
                     raise RuntimeError(
                         "Python interpreter version equal "
                         "to defined lambda runtime ({}) should be "
-                        "available in system PATH".format(runtime))
+                        "available in system PATH".format(command))
 
                 step('pip', runtime, requirements, prefix, tmp_dir)
                 hash(requirements)
 
         def npm_requirements_step(path, prefix=None, required=False, tmp_dir=None):
+            command = "npm"
             requirements = path
             if os.path.isdir(path):
                 requirements = os.path.join(path, 'package.json')
@@ -675,11 +677,10 @@ def npm_requirements_step(path, prefix=None, required=False, tmp_dir=None):
                     raise RuntimeError(
                         'File not found: {}'.format(requirements))
             else:
-                if not query.docker and not shutil.which(runtime):
+                if not query.docker and not shutil.which(command):
                     raise RuntimeError(
-                        "Nodejs interpreter version equal "
-                        "to defined lambda runtime ({}) should be "
-                        "available in system PATH".format(runtime))
+                        "Nodejs package manager ({}) should be "
+                        "available in system PATH".format(command))
 
                 step('npm', runtime, requirements, prefix, tmp_dir)
                 hash(requirements)