add invoke method, utilize in tests

Author: willronchetti

aws_lambda/aws_lambda.py

@@ -286,13 +286,22 @@ def update_function(cfg, path_to_zip_file, extra_config=None):
     client.update_function_configuration(**lambda_update_config)
 
 
-def function_exists(cfg, function_name):
-    """Check whether a function exists or not"""
-
+def _client_from_cfg(cfg):
+    """
+    Helper method for the below methods that sets up a lambda client given
+    a config dictionary containing the relevant AWS key.
+    """
     aws_access_key_id = cfg.get('aws_access_key_id')
     aws_secret_access_key = cfg.get('aws_secret_access_key')
-    client = get_client('lambda', aws_access_key_id, aws_secret_access_key,
+    region = cfg.get('region', 'us-east-1')
+    return get_client('lambda', aws_access_key_id, aws_secret_access_key,
                         cfg.get('region'))
+
+
+def function_exists(cfg, function_name):
+    """Check whether a function exists or not"""
+
+    client = _client_from_cfg(cfg)
     try:
         client.get_function(FunctionName=function_name)
     except:
@@ -306,13 +315,42 @@ def delete_function(cfg, function_name):
     Returns True in success, False otherwise
     """
 
-    aws_access_key_id = cfg.get('aws_access_key_id')
-    aws_secret_access_key = cfg.get('aws_secret_access_key')
-    client = get_client('lambda', aws_access_key_id, aws_secret_access_key,
-                        cfg.get('region'))
+    client = _client_from_cfg(cfg)
     try:
         client.get_function(FunctionName=function_name)
         client.delete_function(FunctionName=function_name)
     except:
         return False
     return True
+
+def invoke_function(cfg, function_name, invocation_type='RequestResponse', event={}):
+    """
+    Invokes the given lambda function using the given client.
+
+    invocation_type is one of 'Event'|'RequestResponse'|'DryRun'. The default
+    is RequestResponse, which will cause this function to hang until the lambda
+    is completed. 'Event' triggers the lambda asynchronously. 'DryRun' just
+    validates paremeters/permissions.
+
+    event is a dictionary containing the arguments needed for this lambda. For
+    example if your lambda is expecting fields 'a' and 'b' in the 'event' that is
+    passed to it from AWS, you would pass in:
+
+        event = {'a': 5, 'b': 13}
+
+    to this function. This information is serialized into JSON and passed to Boto3
+
+    Returns decoded response in success, None otherwise
+    """
+
+    import json
+    client = _client_from_cfg(cfg)
+    try:
+        resp = client.invoke(FunctionName=function_name,
+                             InvocationType=invocation_type,
+                             Payload=json.dumps(event))
+    except:
+        log.error('Failed to execute lambda fxn: %s with arguments: \n %s \n %s'
+                    % (function_name, invocation_type, event))
+        return None
+    return resp['Payload'].read().decode('utf-8')

conftest.py

@@ -2,13 +2,10 @@
 import pytest
 from aws_lambda.aws_lambda import (
     deploy_function,
-    _install_packages,
-    pip_install_to_target,
     get_role_name,
     get_account_id,
     get_client,
-    create_function,
-    update_function,
     function_exists,
-    delete_function
+    delete_function,
+    invoke_function
 )

tests/test_aws_lambda.py

@@ -29,12 +29,6 @@ def cfg(aws_keys):
     return conf
 
 
-@pytest.fixture
-def lambda_client(aws_keys):
-    key_id, secret = aws_keys
-    return get_client('lambda', key_id, secret, region='us-east-1')
-
-
 class TestPythonLambdaUnit():
     """ Class containing unit (non-integration) tests for Python-Lambda """
 
@@ -75,7 +69,7 @@ class TestPythonLambdaIntegration():
 
     pytestmark = [pytest.mark.integration]
 
-    def test_deploy_lambda(self, cfg, lambda_client):
+    def test_deploy_lambda(self, cfg):
         """
         Deploys a lambda function, tests that we can see/use it
         Updates that same function with different config, invokes to verify the
@@ -85,15 +79,15 @@ def test_deploy_lambda(self, cfg, lambda_client):
         full_name = example_function.config['function_name'] + '_' + suff
         deploy_function(example_function, function_name_suffix=suff)
         assert function_exists(cfg, full_name)
-        resp = lambda_client.invoke(FunctionName=full_name, InvocationType='RequestResponse')
-        assert resp['Payload'].read().decode('utf-8') == '"Hello! My input event is {}"'
+        resp = invoke_function(cfg, full_name)
+        assert resp == '"Hello! My input event is {}"'
         deploy_function(example_function_update, function_name_suffix=suff)
-        resp = lambda_client.invoke(FunctionName=full_name, InvocationType='RequestResponse')
-        assert resp['Payload'].read().decode('utf-8') == '"Hello! I have been updated! My input event is {}"'
+        resp = invoke_function(cfg, full_name)
+        assert resp == '"Hello! I have been updated! My input event is {}"'
         assert delete_function(cfg, full_name)
         assert not delete_function(cfg, full_name)
 
-    def test_deploy_lambda_with_requirements(self, cfg, lambda_client):
+    def test_deploy_lambda_with_requirements(self, cfg):
         """
         Deploys and invokes a lambda that has requirements, this time with no suffix
         Also passes an argument that is checked
@@ -103,24 +97,22 @@ def test_deploy_lambda_with_requirements(self, cfg, lambda_client):
         req_fpath = './tests/test_lambdas/requirements.txt'
         deploy_function(function_with_requirements, requirements_fpath=req_fpath)
         assert function_exists(cfg, full_name)
-        resp = lambda_client.invoke(FunctionName=full_name,
-                                    InvocationType='RequestResponse',
-                                    Payload=json.dumps({'magic': 17}))
-        assert resp['Payload'].read().decode('utf-8') == '"I successfully imported pytest! Magic: 17"'
+        resp = invoke_function(cfg, full_name, event={'magic': 17})
+        assert resp == '"I successfully imported pytest! Magic: 17"'
         assert delete_function(cfg, full_name)
 
-    def test_deploy_lambda_with_package(self, cfg, lambda_client):
+    def test_deploy_lambda_with_package(self, cfg):
         """
         Deploys and invokes a lambda that has package based dependencies
         """
         full_name = function_with_package.config['function_name']
         deploy_function(function_with_package, package_objects=[package])
         assert function_exists(cfg, full_name)
-        resp = lambda_client.invoke(FunctionName=full_name, InvocationType='RequestResponse')
-        assert resp['Payload'].read().decode('utf-8') == '"I successfully called magic_function: 21"'
+        resp = invoke_function(cfg, full_name)
+        assert resp == '"I successfully called magic_function: 21"'
         assert delete_function(cfg, full_name)
 
-    def test_deploy_lambda_with_package_and_requirements(self, cfg, lambda_client):
+    def test_deploy_lambda_with_package_and_requirements(self, cfg):
         """
         Deploys and invokes a lambda that uses both an independently packaged
         dependency and one given from requirements.
@@ -130,6 +122,14 @@ def test_deploy_lambda_with_package_and_requirements(self, cfg, lambda_client):
         deploy_function(function_with_req_pack, requirements_fpath=req_fpath,
                         package_objects=[package])
         assert function_exists(cfg, full_name)
-        resp = lambda_client.invoke(FunctionName=full_name, InvocationType='RequestResponse')
-        assert resp['Payload'].read().decode('utf-8') == '"Imported pytest, magic_function: 21"'
+        resp = invoke_function(cfg, full_name)
+        assert resp == '"Imported pytest, magic_function: 21"'
         assert delete_function(cfg, full_name)
+
+    def test_invoke_invalid_lambda(self, cfg):
+        """
+        Tries to execute an invalid lambda. Should fail
+        """
+        full_name = 'not_a_lambda_name'
+        resp = invoke_function(cfg, full_name)
+        assert resp is None