AWS Lambda Cheatsheet

This cheatsheet is probably based on Python

import boto3
client = boto3.client('lambda')
# Role ARN can be found on the top right corner of the Lambda function
response = client.add_permission(
    FunctionName='string',
    StatementId='string',
    Action='string',
    Principal='string',
    SourceArn='string',
    SourceAccount='string',
    EventSourceToken='string',
    Qualifier='string'
)

Troubleshooting
Error	Possible Reason	Solution
File “/var/task/lambda_function.py”, line 2, in lambda_handler return event[‘demoevent’] KeyError: ‘demoevent’	Event does not have the key ‘demoevent’ or either misspelled	Make sure the event is getting the desired key if it is receiving the event from any trigger. Or if the not outside event is passed than check for misspell. Or check the event list by printing event.
botocore.exceptions.ClientError: An error occurred (AccessDeniedException) when calling the GetParameters operation: User: arndummy:assumed-role/role/ is not authorized to perform: ssm:GetParameters on resource: arnssm:dummy	Lacks Permission to access	Assign appropriate permission for accessibility
ImportError: Missing required dependencies [‘module’]	Dependent module is missing	Install/Upload the required module
sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) could not translate host name “host.dummy.region.rds.amazonaws.com” to address: Name or service not known	RDS Host is unavailable	Make sure the RDS instance is up and running. Double check the RDS hostname
[Errno 32] Broken pipe	Connection is lost (Either from your side or may be some problem from AWS) While invoking another Lambda, if the payload size exceed the mentioned limit	Make sure if you are passing the payload of right size. Check for the connection.
Unable to import module ‘lambda_function/index’ No module named ‘lambda_function’	Handler configuration is not matching the main file name	Update the handler configuration as per your filename.function_name
OperationalError: (psycopg2.OperationalError) terminating connection due to administrator command SSL connection has been closed unexpectedly	RDS/Database System has been rebooted. In a typical web application using an ORM (SQLAlchemy) Session, the above condition would correspond to a single request failing with a 500 error, then the web application continuing normally beyond that. Hence the approach is “optimistic” in that frequent database restarts are not anticipated.	Give second try
Error code 429	The function is throttled. Basically the reserved concurrency is set to zero or it have reach the account level throttle. (The function that is invoked synchronous and if it is throttled then it will return 429 error. If the lambda function is invoked asynchronously and if it is throttled then it will retry the throttled event for upto 6 hours.)	Check for the reserved concurrency limit or throttle status for the individual function. Or check for the account level concurrent execution limit

AWS Lambda CLI commands

It add mention permission to the Lambda function

Syntax

  add-permission
--function-name <value>
--statement-id <value>
--action <value>
--principal <value>
[--source-arn <value>]
[--source-account <value>]
[--event-source-token <value>]
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

add-permission --function-name functionName --statement-id role-statement-id --action lambda:CreateFunction --principal s3.amazonaws.com

Create Alias

It creates alias for the given Lambda function name

Syntax

  create-alias
--function-name <value>
--name <value>
--function-version <value>
[--description <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

create-alias --function-name functionName --name fliasName --function-version version

Create Event Source Mapping

It identify event-source from Amazon Kinesis stream or an Amazon DynamoDB stream

  create-event-source-mapping
--event-source-arn <value>
--function-name <value>
[--enabled | --no-enabled]
[--batch-size <value>]
--starting-position <value>
[--starting-position-timestamp <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

create-event-source-mapping --event-source-arn arn:aws:kinesis:us-west-1:1111 --function-name functionName --starting-position LATEST

Create Function

It creates the new function

Syntax

  create-function
--function-name <value>
--runtime <value>
--role <value>
--handler <value>
[--code <value>]
[--description <value>]
[--timeout <value>]
[--memory-size <value>]
[--publish | --no-publish]
[--vpc-config <value>]
[--dead-letter-config <value>]
[--environment <value>]
[--kms-key-arn <value>]
[--tracing-config <value>]
[--tags <value>]
[--zip-file <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

create-function --function-name functionName --runtime python3.6 --role arn:aws:iam::account-id:role/lambda_basic_execution
 --handler main.handler

Delete Alias

It deletes the alias

Syntax

  delete-alias
--function-name <value>
--name <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

delete-alias --function-name functionName --name aliasName

Delete Event Source Mapping

It deletes the event source mapping

Syntax

  delete-event-source-mapping
--uuid <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

delete-event-source-mapping --uuid 12345kxodurf3443

Delete Function

It will delete the function and all the associated settings

Syntax

  delete-function
--function-name <value>
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

delete-function --function-name FunctionName

Get Account Settings

It will fetch the user’s account settings

Syntax

  get-account-settings
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Get Alias

It returns the desired alias information like description, ARN

Syntax

  get-alias
--function-name <value>
--name <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

get-alias --function-name functionName --name aliasName

Get Event Source Mapping

It returns the config information for the desired event source mapping

Syntax

  get-event-source-mapping
--uuid <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

get-event-source-mapping --uuid 12345kxodurf3443

Get Function

It returns the Lambda Function information

Syntax

  get-function
--function-name <value>
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

get-function --function-name functionName

Get Function Configuration

It returns the Lambda function configuration

Syntax

  get-function-configuration
--function-name <value>
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

  get-function-configuration --function-name functionName

Get Policy

It return the linked policy with Lambda function

Syntax

  get-policy
--function-name <value>
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

get-policy --function-name functionName

Invoke

It invoke the mention Lambda function name

invoke
—function-name
[—invocation-type ]
[—log-type ]
[—client-context ]
[—payload ]
[—qualifier ]

Example

invoke --function-name functionName

List Aliases

It return all the aliases that is created for Lambda function

Syntax

  list-aliases
--function-name <value>
[--function-version <value>]
[--marker <value>]
[--max-items <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

  list-aliases --function-name functionName

List Event Source Mappings

It return all the list event source mappings that is created with create-event-source-mapping

Syntax

  list-event-source-mappings
[--event-source-arn <value>]
[--function-name <value>]
[--max-items <value>]
[--cli-input-json <value>]
[--starting-token <value>]
[--page-size <value>]
[--generate-cli-skeleton <value>]

Example

  list-event-source-mappings --event-source-arn arn:aws:arn --function-name functionName

List Functions

It return all the Lambda function

Syntax

  list-functions
[--master-region <value>]
[--function-version <value>]
[--max-items <value>]
[--cli-input-json <value>]
[--starting-token <value>]
[--page-size <value>]
[--generate-cli-skeleton <value>]

Example

  list-functions --master-region us-west-1 --function-version ALL

List Tags

It return the list of tags that are assigned to the Lambda function

Syntax

  list-tags
--resource <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

  list-tags --resource arn:aws:function

List Versions by functions

It return all the versions of the desired Lambda function

Syntax

  list-versions-by-function
--function-name <value>
[--marker <value>]
[--max-items <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

list-versions-by-function --function-name functionName

Publish Version

It publish the version of the Lambda function from $LATEST snapshot

Syntax

  publish-version
--function-name <value>
[--code-sha-256 <value>]
[--description <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

  publish-version --function-name functionName

Remove Permission

It remove the single permission from the policy that is linked with the Lambda function

Syntax

 remove-permission
--function-name <value>
--statement-id <value>
[--qualifier <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

 remove-permission --function-name functionName --statement-id role-statement-id

Tag Resource

It creates the tags for the lambda function in the form of key-value pair

Syntax

  tag-resource
--resource <value>
--tags <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

tag-resource --resource arn:aws:arn --tags {‘key’: ‘pair’}

Untag Resource

It remove tags from the Lambda function

Syntax

 untag-resource
--resource <value>
--tag-keys <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

untag-resource --resource arn:aws:complete --tag-keys [‘key1’, ‘key2’]

Update Alias

It update the alias name of the desired lambda function

Syntax

  update-alias
--function-name <value>
--name <value>
[--function-version <value>]
[--description <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

update-alias --function-name functionName --name aliasName

Update Event Source Mapping

It updates the event source mapping incase you want to change the existing parameters

Syntax

  update-event-source-mapping
--uuid <value>
[--function-name <value>]
[--enabled | --no-enabled]
[--batch-size <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

update-event-source-mapping --uuid 12345kxodurf3443

Update Function Code

It updates the code of the desired Lambda function

Syntax

  update-function-code
--function-name <value>
[--zip-file <value>]
[--s3-bucket <value>]
[--s3-key <value>]
[--s3-object-version <value>]
[--publish | --no-publish]
[--dry-run | --no-dry-run]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

update-function-code --function-name functionName

Update Function Configuration

It updates the configuration of the desired Lambda function

Syntax

  update-function-configuration
--function-name <value>
[--role <value>]
[--handler <value>]
[--description <value>]
[--timeout <value>]
[--memory-size <value>]
[--vpc-config <value>]
[--environment <value>]
[--runtime <value>]
[--dead-letter-config <value>]
[--kms-key-arn <value>]
[--tracing-config <value>]
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Example

update-function-configuration --function-name functionName

References

• AWS Lambda Docs


• Boto 3 Docs


• AWS CLI Docs


• SQLAlchemy Docs