added explanation about the necessary role for the function and clarification of the use of credentials in localstack

example-projects/counter-demo/aws-lambda-localstack/aws-mockup-credentials/credentials

@@ -1,3 +1,7 @@
 [default]
 aws_access_key_id=test
 aws_secret_access_key=test
+
+# not necessary at all... you can use any aws_access_key, aws_secret_key and session to talk to
+# localstack as it is a mockup/emulation of AWS. So you can even reuse your AWS Academy credentials
+# to also connect to localstack

example-projects/counter-demo/aws-lambda-localstack/start.py

@@ -9,28 +9,35 @@ from botocore.exceptions import ClientError
 #
 ################################################################################################
 
+# main change from real AWS Academy access to local emulated localstack is to change the endpoint
+# other than that the same tools (boto3, aws-cli, aws-cdk etc. can be used)
 endpoint_url = "http://localhost.localstack.cloud:4566"
 
-# you need to create a bucket in S3, here in this demo it is called "cloudcomp-counter", but
-# bucket names need to be world wide unique ;) The demo looks for a file that is named
-# "us-east-1" (same as our default region) in the bucket and expects a number in it to increase
-
+# a bucket in S3 will be created to store the counter bucket names need to be world-wide unique ;)
+# Hence we create a bucket name that contains your group number and the current year.
+# The counter will be stores as key (file) "us-east-1" in the bucket (same name as our default region)
+# in the bucket and expects a number in it to increase
 groupNr = 22
 currentYear = date.today().year
-
 globallyUniqueS3GroupBucketName = "cloudcomp-counter-" + str(currentYear) + "-group" + str(groupNr)
 
 # region = 'eu-central-1'
 region = 'us-east-1'
 functionName = 'cloudcomp-counter-lambda-demo'
 
+# The Lambda function will run using privileges of a role, that allows the function to access/create
+# resources in AWS (in this case read/write to S3). In AWS Academy you need to use the role that
+# use created for your student account in the lab (see lab readme).
 # see ARN for AWS Academy LabRole function here:
 # https://us-east-1.console.aws.amazon.com/iamv2/home?region=us-east-1#/roles/details/LabRole?section=permissions
-
+#
 # roleArn = 'arn:aws:iam::309000625112:role/service-role/cloudcomp-counter-demo-role-6rs7pah3'
 # roleArn = 'arn:aws:iam::919927306708:role/cloudcomp-s3-access'
 roleArn = 'arn:aws:iam::488766701848:role/LabRole'
 
+# For localstack you can use any role Arn and every secret and access key. Hence you can also use
+# existing AWS Academy credentials to connect to localstack
+
 ################################################################################################
 #
 # boto3 code

example-projects/counter-demo/aws-lambda-localstack/stop.py

@@ -10,13 +10,8 @@ from botocore.exceptions import ClientError
 
 endpoint_url = "http://localhost.localstack.cloud:4566"
 
-# you need to create a bucket in S3, here in this demo it is called "cloudcomp-counter", but
-# bucket names need to be world wide unique ;) The demo looks for a file that is named
-# "us-east-1" (same as our default region) in the bucket and expects a number in it to increase
-
 groupNr = 22
 currentYear = date.today().year
-
 globallyUniqueS3GroupBucketName = "cloudcomp-counter-" + str(currentYear) + "-group" + str(groupNr)
 
 # region = 'eu-central-1'

example-projects/counter-demo/aws-lambda/start.py

@@ -9,10 +9,10 @@ from botocore.exceptions import ClientError
 #
 ################################################################################################
 
-# you need to create a bucket in S3, here in this demo it is called "cloudcomp-counter", but
-# bucket names need to be world wide unique ;) The demo looks for a file that is named
-# "us-east-1" (same as our default region) in the bucket and expects a number in it to increase
-
+# a bucket in S3 will be created to store the counter bucket names need to be world-wide unique ;)
+# Hence we create a bucket name that contains your group number and the current year.
+# The counter will be stores as key (file) "us-east-1" in the bucket (same name as our default region)
+# in the bucket and expects a number in it to increase
 groupNr = 22
 currentYear = date.today().year
 
@@ -22,13 +22,21 @@ globallyUniqueS3GroupBucketName = "cloudcomp-counter-" + str(currentYear) + "-gr
 region = 'us-east-1'
 functionName = 'cloudcomp-counter-lambda-demo'
 
+# The Lambda function will run using privileges of a role, that allows the function to access/create
+# resources in AWS (in this case read/write to S3). In AWS Academy you need to use the role that
+# use created for your student account in the lab (see lab readme).
 # see ARN for AWS Academy LabRole function here:
 # https://us-east-1.console.aws.amazon.com/iamv2/home?region=us-east-1#/roles/details/LabRole?section=permissions
-
+#
 # roleArn = 'arn:aws:iam::309000625112:role/service-role/cloudcomp-counter-demo-role-6rs7pah3'
 # roleArn = 'arn:aws:iam::919927306708:role/cloudcomp-s3-access'
 # roleArn = 'arn:aws:iam::488766701848:role/LabRole'
 
+# standard name for role in AWS Academy lab created by vocareum is "LabRole". See README of the
+# lab. The following code will lookup the AWS Resource Name (ARN) (sort of the ID for this role)
+# that has the following name:
+roleName = "LabRole"
+
 ################################################################################################
 #
 # boto3 code
@@ -56,7 +64,7 @@ print("Getting AWS Academy LabRole ARN...")
 print("------------------------------------")
 response = iamClient.list_roles()
 for role in response["Roles"]:
-    if role["RoleName"] == "LabRole":
+    if role["RoleName"] == roleName:
         roleArn = role["Arn"]
         print(roleArn)
 
@@ -136,18 +144,12 @@ print("Lambda Function and S3 Bucket to store the counter are available. Sadly,
 # that would call our function, as in the provided demo:
 #
 # https://348yxdily0.execute-api.eu-central-1.amazonaws.com/default/cloudcomp-counter-demo
-
+#
 # print("creating API gateway...")
 # print("------------------------------------")
 #
-# #apiArn = ""
 # response = apiClient.create_api(
 #     Name=functionName + '-api',
 #     ProtocolType='HTTP',
 #     Target=lambdaFunctionARN
 # )
-# #apiArn=response['']
-#
-# #response = lClient.create_event_source_mapping(
-# #    EventSourceArn=apiArn,
-# #)

example-projects/counter-demo/aws-lambda/stop.py

@@ -8,13 +8,8 @@ from botocore.exceptions import ClientError
 #
 ################################################################################################
 
-# you need to create a bucket in S3, here in this demo it is called "cloudcomp-counter", but
-# bucket names need to be world wide unique ;) The demo looks for a file that is named
-# "us-east-1" (same as our default region) in the bucket and expects a number in it to increase
-
 groupNr = 22
 currentYear = date.today().year
-
 globallyUniqueS3GroupBucketName = "cloudcomp-counter-" + str(currentYear) + "-group" + str(groupNr)
 
 # region = 'eu-central-1'