aws-org-view 0.0.3

Python helper library that provides a high-level, cached view of AWS Organizations

aws-org-view

A small Python helper library that provides a high-level, cached view of AWS Organizations.

It is designed to be aggressively cache-heavy and lazy by default:

• Results from AWS Organizations APIs are stored in TTL caches to minimise repeated API calls
• Queries only perform the minimum number of API calls required to resolve the specific question being asked (for example, stopping parent traversal as soon as a match is found)

It wraps the low-level AWS Organizations API calls (via boto3) to make common “org structure” queries easier, including:

• Checking whether an account belongs under a given OU/root (or matches any ID in a “haystack”)
• Building a nested OU → accounts hierarchy tree, optionally only one level deep
• Reducing repeated API calls with TTL caches (helpful when walking parent chains or listing lots of OUs/accounts)

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Install

pip install aws-org-view

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Quickstart

from aws_org_view import AwsOrgView

org = AwsOrgView()  # uses boto3.client("organizations") by default

# Example: check if account "123456789012" is within ou-abcd-xyz987 or ou-abcd-wft745 - either directly or in one of their descendant OUs.
found = org.account_in_haystack(
    account_id="123456789012",
    haystack=["ou-abcd-xyz987", "ou-abcd-wft745"],  # OUs, roots, and/or account IDs
)
print(found)

# Example: build a full OU hierarchy (root -> all descendants)
tree = org.get_ou_hierarchy()
print(tree)

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What AwsOrgView does

Caching

AwsOrgView maintains several cachetools.TTLCache instances to avoid repeated AWS calls within a time window:

• Parent lookups (list_parents)
• Organization root ID (list_roots)
• OU descriptions (describe_organizational_unit)
• Accounts under a parent (list_accounts_for_parent)
• Child OUs under a parent (list_organizational_units_for_parent)

You can control cache size and TTL:

org = AwsOrgView(cache_ttl=900, cache_maxsize=1024)  # 15 min TTL

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Using account_in_haystack()

Purpose

account_in_haystack() answers:

“Does this account appear in (or sit underneath) any ID in this set of IDs?”

It walks upwards from the account:

account -> parent OU -> ... -> root

At each step it checks if the current ID is present in your haystack.

Signature

def account_in_haystack(
    self,
    account_id: str,
    haystack: set[str] | list[str],
    require_direct_descendant: bool = False,
) -> bool:

Examples

1) Account is directly listed in the haystack

org.account_in_haystack(
    account_id="123456789012",
    haystack=["123456789012"],
)
# -> True

2) Account is under an OU in the haystack

org.account_in_haystack(
    account_id="123456789012",
    haystack=["ou-abcd-xyz987"],
)
# -> True if that OU is in the account’s parent chain

3) Account is somewhere under the org root in the haystack

org.account_in_haystack(
    account_id="123456789012",
    haystack=["r-a1b2"],
)

4) Only count direct children of a target OU/root

If require_direct_descendant=True, the function only checks:

• the account itself, and
• its immediate parent

This is useful if you only consider an account “in scope” when it is directly attached to a given OU/root (not nested multiple OUs deep).

org.account_in_haystack(
    account_id="123456789012",
    haystack=["ou-abcd-xyz987"],
    require_direct_descendant=True,
)

Notes / behavior

• haystack can be a list or a set; lists are converted to a set.
• The code limits traversal depth to 6 checks (AWS supports up to 5 OU levels plus the root).
• If AWS returns anything other than exactly one parent for an entity, a ParentResolutionError is raised.

---

Using get_ou_hierarchy()

Purpose

get_ou_hierarchy() builds a nested dictionary representing:

• an OU/root node’s name
• its direct accounts
• its child OUs
• recursively, the children of those OUs (unless you request only one level)

Signature

def get_ou_hierarchy(
    self,
    parent_id: str | None = None,
    direct_descendants_only: bool = False
) -> OUMembershipRetrieverResult:

Examples

1) Full org tree from the root

org = AwsOrgView()
tree = org.get_ou_hierarchy()  # parent_id=None => use org root

2) Tree rooted at a specific OU

tree = org.get_ou_hierarchy(parent_id="ou-abcd-xyz987")

3) Only include immediate child OUs (no recursion)

tree = org.get_ou_hierarchy(direct_descendants_only=True)

With direct_descendants_only=True, the output includes:

• accounts at the parent node
• immediate org_units entries with only their name

It will not recursively populate grandchildren OUs.

Returned structure

The return value is an OUMembershipRetrieverResult, which is a dict wrapper. The top-level dict has a single key: the root ID you requested (OU ID or root ID). That key maps to a node shaped like:

{
  "<parent_id>": {
    "name": "<friendly name>",
    "accounts": [ ...accounts directly under this parent... ],
    "org_units": {
      "<child_ou_id>": {
        "name": "<child ou name>",
        "accounts": [...],
        "org_units": {...}
      },
      ...
    }
  }
}

Getting a flat list of all accounts

OUMembershipRetrieverResult provides:

accounts = tree.get_accounts()

That recursively walks the tree and returns a single flat list of account objects.

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Using a custom client

There are two supported customisation styles:

1. Pass a pre-built boto3 Organizations client
2. Pass a client provider (recommended when you need refresh/assume-role logic)

1) Pass a boto3 Organizations client

import boto3
from aws_org_view import AwsOrgView

client = boto3.client("organizations")
org = AwsOrgView(client=client)

2) Pass a custom OrganizationsClientProvider

The library defines a runtime-checkable protocol:

class OrganizationsClientProvider(Protocol):
    def get_client(self) -> OrganizationsClient: ...

Your provider can do anything internally (assume role, refresh credentials, add custom config), as long as it returns a valid Organizations client from get_client().

Example: provider using a named AWS profile

import boto3
from aws_org_view import AwsOrgView

class ProfileOrganizationsClientProvider:
    def __init__(self, profile_name: str):
        self._session = boto3.Session(profile_name=profile_name)

    def get_client(self):
        return self._session.client("organizations")

org = AwsOrgView(client=ProfileOrganizationsClientProvider("prod-admin"))

Example: provider that assumes a role

import boto3
from aws_org_view import AwsOrgView

class AssumeRoleOrganizationsClientProvider:
    def __init__(self, role_arn: str, session_name: str = "aws-org-view"):
        self._sts = boto3.client("sts")
        self._role_arn = role_arn
        self._session_name = session_name

    def get_client(self):
        creds = self._sts.assume_role(
            RoleArn=self._role_arn,
            RoleSessionName=self._session_name,
        )["Credentials"]

        session = boto3.Session(
            aws_access_key_id=creds["AccessKeyId"],
            aws_secret_access_key=creds["SecretAccessKey"],
            aws_session_token=creds["SessionToken"],
        )
        return session.client("organizations")

org = AwsOrgView(
    client=AssumeRoleOrganizationsClientProvider(
        "arn:aws:iam::123456789012:role/OrgReadRole"
    )
)

Development

Create (and remove if needed) the Hatch dev environment.

hatch env remove dev
hatch env create dev

Run tests: hatch run dev:fmt

Run code linting: hatch run dev:pytest

Run code type checking: hatch run dev:typing

License

aws-org-view is distributed under the terms of the MIT license.

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Python written by humans. English written by AI.