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Module: iam-s3-user

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.

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/*"
}

Variables

Required Variables

s3_resources (list(string)) required

S3 resources to apply the actions specified in the policy

Optional Variables

create_iam_access_key (bool) optional

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.



Default value: true

force_destroy (bool) optional

Destroy even if it has non-Terraform-managed IAM access keys, login profiles or MFA devices


Default value: false

path (string) optional

Path in which to create the user


Default value: "/"

permissions_boundary (string) optional

Permissions Boundary ARN to attach to our created user


Default value: null

s3_actions (list(string)) optional

Actions to allow in the policy


Default value:

[
"s3:GetObject"
]
ssm_base_path (string) optional

The base path for SSM parameters where secrets are stored


Default value: "/s3_user/"

ssm_enabled (bool) optional

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.



Default value: false

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

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.


Required: No

Default value: { }

attributes (list(string)) optional

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.


Required: No

Default value: [ ]

context (any) optional

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.


Required: No

Default value:

{
"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
}
delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.


Required: No

Default value: null

descriptor_formats (any) optional

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).


Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

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.


Required: No

Default value: null

label_key_case (string) optional

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.


Required: No

Default value: null

label_order (list(string)) optional

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.


Required: No

Default value: null

label_value_case (string) optional

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.


Required: No

Default value: null

labels_as_tags (set(string)) optional

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.


Required: No

Default value:

[
"default"
]
name (string) optional

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.


Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

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.


Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.


Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs

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

Dependencies

Requirements

  • terraform, version: >= 0.13.0
  • aws, version: >= 2.0

Providers

  • aws, version: >= 2.0

Modules

NameVersionSourceDescription
s3_user1.2.1cloudposse/iam-system-user/awsn/a
this0.25.0cloudposse/label/nulln/a

Resources

The following resources are used by this module:

Data Sources

The following data sources are used by this module: