Terraform module to provision a basic IAM user with permissions to access S3 resources, e.g. to give the user read/write/delete access to the objects in an S3 bucket.

Suitable for CI/CD systems (e.g. TravisCI, CircleCI) or systems which are external to AWS that cannot leverage AWS IAM Instance Profiles or AWS OIDC.

By default, IAM users, groups, and roles have no access to AWS resources. IAM policies are the means by which privileges are granted to users, groups, or roles. It is recommended that IAM policies be applied directly to groups and roles but not users. This module intentionally attaches an IAM policy directly to the user and does not use groups

The IAM user name is constructed using terraform-null-label and some input is required. The simplest input is name. By default the name will be converted to lower case and all non-alphanumeric characters except for hyphen will be removed. See the documentation for terraform-null-label to learn how to override these defaults if desired.

If an AWS Access Key is created, it is stored either in SSM Parameter Store or is provided as a module output, but not both. Using SSM Parameter Store is recommended because module outputs are stored in plaintext in the Terraform state file.

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Usage

This example will create an IAM user and allow read access to all objects in the S3 bucket examplebucket

module "s3_user" {
  source = "cloudposse/iam-s3-user/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"
  namespace    = "eg"
  stage        = "test"
  name         = "app"
  s3_actions   = ["s3:GetObject"]
  s3_resources = "arn:aws:s3:::examplebucket/*"
}

Important

In Cloud Posse's examples, we avoid pinning modules to specific versions to prevent discrepancies between the documentation and the latest released versions. However, for your own projects, we strongly advise pinning each module to the exact version you're using. This practice ensures the stability of your infrastructure. Additionally, we recommend implementing a systematic approach for updating versions to avoid unexpected changes.

Makefile Targets

Available targets:

  help                                Help screen
  help/all                            Display help for all targets
  help/short                          This help short screen
  lint                                Lint terraform code

Requirements

Name	Version
terraform	>= 0.13.0
aws	>= 2.0

Providers

Name	Version
aws	>= 2.0

Modules

Name	Source	Version
s3_user	cloudposse/iam-system-user/aws	1.2.1
this	cloudposse/label/null	0.25.0

Resources

Name	Type
aws_iam_user_policy.default	resource
aws_iam_policy_document.default	data source

Inputs

Name	Description	Type	Default	Required
additional_tag_map	Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	map(string)	{}	no
attributes	ID element. Additional attributes (e.g. workers or cluster) to add to id, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the delimiter and treated as a single ID element.	list(string)	[]	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }	no
create_iam_access_key	Set true to create an IAM Access Key for the user. To rotate the key, set false to delete it and then back to true to create a new key. Best practice is to never create a key and instead authenticate with OIDC or some other mechanism that does not require long-lived bearer tokens.	bool	true	no
delimiter	Delimiter to be used between ID elements. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
descriptor_formats	Describe additional descriptors to be output in the descriptors output map. Map of maps. Keys are names of descriptors. Values are maps of the form {<br/> format = string<br/> labels = list(string)<br/>} (Type is any so the map values can later be enhanced to provide additional options.) format is a Terraform format string to be passed to the format() function. labels is a list of labels, in order, to pass to format() function. Label values will be normalized before being passed to format() so they will be identical to how they appear in id. Default is {} (descriptors output will be empty).	any	{}	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	string	null	no
force_destroy	Destroy even if it has non-Terraform-managed IAM access keys, login profiles or MFA devices	bool	false	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for keep the existing setting, which defaults to 0. Does not affect id_full.	number	null	no
label_key_case	Controls the letter case of the tags keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the tags input. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The order in which the labels (ID elements) appear in the id. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	list(string)	null	no
label_value_case	Controls the letter case of ID elements (labels) as included in id, set as tag values, and output by this module individually. Does not affect values of tags passed in via the tags input. Possible values: lower, title, upper and none (no transformation). Set this to title and set delimiter to "" to yield Pascal Case IDs. Default value: lower.	string	null	no
labels_as_tags	Set of labels (ID elements) to include as tags in the tags output. Default is to include all labels. Tags with empty values will not be included in the tags output. Set to [] to suppress all generated tags. Notes: The value of the name tag, if included, will be the id, not the name. Unlike other null-label inputs, the initial setting of labels_as_tags cannot be changed in later chained modules. Attempts to change it will be silently ignored.	set(string)	[ "default" ]	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a tag. The "name" tag is set to the full id string. There is no tag with the value of the name input.	string	null	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	string	null	no
path	Path in which to create the user	string	"/"	no
permissions_boundary	Permissions Boundary ARN to attach to our created user	string	null	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
s3_actions	Actions to allow in the policy	list(string)	[ "s3:GetObject" ]	no
s3_resources	S3 resources to apply the actions specified in the policy	list(string)	n/a	yes
ssm_base_path	The base path for SSM parameters where secrets are stored	string	"/s3_user/"	no
ssm_enabled	Set true to store secrets in SSM Parameter Store, false to store secrets in Terraform state as outputs. Since Terraform state would contain the secrets in plaintext, use of SSM Parameter Store is recommended.	bool	false	no
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	string	null	no
tags	Additional tags (e.g. {'BusinessUnit': 'XYZ'}). Neither the tag keys nor the tag values will be modified by this module.	map(string)	{}	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	string	null	no

Outputs

Name	Description
access_key_id	Access Key ID
access_key_id_ssm_path	The SSM Path under which the S3 User's access key ID is stored
secret_access_key	Secret Access Key. This will be written to the state file in plain-text
secret_access_key_ssm_path	The SSM Path under which the S3 User's secret access key is stored
user_arn	The ARN assigned by AWS for the user
user_name	Normalized IAM user name
user_unique_id	The user unique ID assigned by AWS

Related Projects

Check out these related projects.

• terraform-aws-iam-system-user - Terraform Module to Provision a Basic IAM System User Suitable for CI/CD Systems (E.g. TravisCI, CircleCI)
• terraform-aws-iam-assumed-roles - Terraform Module for Assumed Roles on AWS with IAM Groups Requiring MFA
• terraform-aws-ssm-iam-role - Terraform module to provision an IAM role with configurable permissions to access SSM Parameter Store
• terraform-aws-iam-chamber-user - Terraform module to provision a basic IAM chamber user with access to SSM parameters and KMS key to decrypt secrets, suitable for CI/CD systems (e.g. TravisCI, CircleCI, CodeFresh) or systems which are external to AWS that cannot leverage AWS IAM Instance Profiles
• terraform-aws-lb-s3-bucket - Terraform module to provision an S3 bucket with built in IAM policy to allow AWS Load Balancers to ship access logs

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