def get_role_credentials(account: str, sts_client: Any) -> dict:
"""
Assumes a role and returns credentials for said role.
Requires the COMMON_PRINCIPAL_NAME to be set, usually from metadata.
Example returned dictionary:
```
{
"Expiration": "2020-01-27T11:55:44Z",
"Token": "abc123",
"SecretAccessKey": "def456",
"AccessKeyId": "ABCDEF123",
"Type": "AWS-SOMETHING",
"LastUpdated": "2020-01-27T10:55:45Z",
"Code": "Success"
}
:param account: An AWS account id number
:type account: str
:param sts_client: an aws client connection to the sts service
:type resource: boto3 client
:returns: Dictionary containing the credentials from the assume role action
:rtype: dict
"""
try:
arn = f'arn:aws:iam::{account}:role/{COMMON_PRINCIPAL_NAME}'
LOGGER.info(f'Attempting to tokenise into: {arn}')
credentials = sts_client.assume_role(RoleArn=arn, RoleSessionName=ROLE_SESSION_NAME)['Credentials']
LOGGER.info(f'Successfully tokenised into: {arn}')
return credentials
except BaseException:
LOGGER.warning("Unexpected error: %s", sys.exc_info()[1], exc_info=True)
return {}
def aws_client(account: str, service: str, region: str):
"""
Initialises a sts client, gets assume role credentials
and initialises a AWS client connection to a requested resource.
Returns the AWS product/resource client connection.
Caches the client connection for re-use.
For reference: http://boto3.readthedocs.io/en/latest/guide/configuration.html
:param account: An AWS account id number
:type account: str
:param service: An AWS service e.g. ec2
:type service: str
:param region: An AWS region where the service client should be created. e.g. us-east-1
:type region: str
"""
global CLIENT_CACHE
# In this block we get credentials for the target account by assuming
# into the given account using a sts client connection
# If we can't we return none and cache none.
if not (credentials := get_role_credentials(account, aws_sts_client())):
LOGGER.warning(
f'Unable to tokenise into {account} for service {service} in region {region}. Moving on'
)
CLIENT_CACHE[account][region][service] = None
return None
def check_iam_role_capability(account_id: str) -> bool:
"""
Check that we can assume a role in each account and perform an ec2 action to validate it.
Allows us to filter out accounts which do not work for the script and inform the user.
:param account_id: An AWS Account Id
:type account_id: str
:returns: True if the role and EC2 client works. False otherwise.
:rtype: bool
"""
try:
if ec2_client := aws_client(account_id, 'ec2', 'us-east-1'):
ec2_client.describe_vpcs()
LOGGER.info(f'Able to assume role in {account_id} and access the EC2 API.')
return True
LOGGER.warning(f'Unable to assume role in {account_id} and access the EC2 API.')
def tag_resource(client, resource: str, tags: dict, dryrun: bool = False):
"""
Tags an AWS resource with the provided tags.
Example Usage:
```
ec2_client = aws_client(account_id, 'ec2', region)
tags = {'peerd_support': '*****@*****.**',
'peerd_datetime': str(datetime.now())}
tag_resource(ec2_client, peerding_id, tags)
```
:param client: An AWS boto3 client connection to an AWS resource
:type client: boto3 client
:param resource: The name of the resource e.g. rt-abc123
:type resource: string
:param tags: Dictionary of tags to apply to a resource
:type tags: dict
:returns: Nothing
:raises BaseException: Raises an exception if there was some problem tagging the resource
"""
tags = [{'Key': key, 'Value': value} for (key, value) in tags.items()]
for x in range(5):
try:
LOGGER.debug(f'Tagging {resource}')
client.create_tags(Resources=[resource], Tags=tags, DryRun=dryrun)
LOGGER.debug(f'Tagging {resource} successful')
return
except botocore.exceptions.ClientError as err:
if err.response['Error']['Code'] == 'DryRunOperation':
LOGGER.debug(f'Tagging {resource} successful')
return
LOGGER.info(
f'Tagging {resource} encountered error: {err.response["Error"]["Message"]}. Will retry.'
)
sleep(1)
continue
except BaseException:
LOGGER.warning("Unexpected error: %s",
sys.exc_info()[1],
exc_info=True)
raise Exception(f'Could not tag resource {resource}')
def clean_route_tables(peering_id: str, vpc_id: str, account_id: str, region: str, dryrun: bool) -> None:
"""
Deletes any routes pointing at a given peering id for a given vpc.
Only applies to route tables with tag peerd_eligible:true
:param peering_id: A vpc peering id e.g. pcx-011a291e5affc8d95
:type peering_id: str
:param vpc_id: A vpc id e.g. vpc-abc123
:type vpc_id: str
:param account_id: An AWS account id number
:type account: str
:param region: An AWS region where the service client should be created. e.g. us-east-1
:type region: str
"""
# Initialise EC2 client
ec2_client = aws_client(account_id, 'ec2', region)
# Get the route tables for the VPC
if not (route_tables := vpc_route_tables(vpc_id, account_id, region)):
LOGGER.warning(f'No peerd_eligible route tables in VPC {vpc_id}')
return
Check that we can assume a role in each account and perform an ec2 action to validate it.
Allows us to filter out accounts which do not work for the script and inform the user.
:param account_id: An AWS Account Id
:type account_id: str
:returns: True if the role and EC2 client works. False otherwise.
:rtype: bool
"""
try:
if ec2_client := aws_client(account_id, 'ec2', 'us-east-1'):
ec2_client.describe_vpcs()
LOGGER.info(f'Able to assume role in {account_id} and access the EC2 API.')
return True
LOGGER.warning(f'Unable to assume role in {account_id} and access the EC2 API.')
except BaseException:
LOGGER.warning(f'Unable to assume role in {account_id} and access the EC2 API.')
LOGGER.error(f'Unexpected error: {sys.exc_info()[1]}', exc_info=True)
return False
@memoize()
def describe_account_vpcs_cached(account_id: str, region: str) -> List[dict]:
"""
Describe all the VPCs in a given account in a given region and return them as a list of descriptions
See https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#EC2.Client.describe_vpcs
:param account_id: An AWS account id number
:type account: str
:param region: An AWS region where the service client should be created. e.g. us-east-1
:type region: str
:returns: A list of dictionaries representing all the VPCs for a given account and region.
def update_route_tables(target_peerings: list, metadata: Mapping,
dryrun: bool) -> None:
"""
Loops through a list of peerings and updates the route tables on each side.
Example target_peerings:
```
[
[
{
"account_id": 415432961280,
"vpc_id": "vpc-e08fb484",
"region": "ap-southeast-2",
"cidr_overrides": [
"10.53.101.0/27"
],
"peering_tags": [
{
"peerd_az_affinity": "0"
}
]
},
{
"account_id": 415432961280,
"vpc_id": "vpc-7a83b81e",
"region": "ap-southeast-2"
}
]
]
```
:param target_peerings: A list of lists representing the requester and accepter for each peering.
:type target_peerings: list
:param metadata: A dictionary with the environment, owner, etc for tagging
:type metadata: list
"""
# We need to handle both sides of the peerings so we append reverse of each peering.
# This means every side of every peering will be seen by a single loop.
# We do this to avoid extra code handling the AWS concept of "accepter" and "requester"
# We also construct our route table cache by account and region, which means if we looped
# by requester and accepter we could cache stale route table contents.
target_peerings.extend([x[::-1] for x in target_peerings])
# Loop through the target peerings
for peering_descriptor in target_peerings:
# Unpack some common variables
account_id = peering_descriptor[0]['account_id']
vpc_id = peering_descriptor[0]['vpc_id']
region = peering_descriptor[0]['region']
remote_account_id = peering_descriptor[1]['account_id']
remote_vpc_id = peering_descriptor[1]['vpc_id']
remote_region = peering_descriptor[1]['region']
# Get the remote CIDRs from the AWS VPC API, or use the overrides in the config if they exist.
remote_cidrs = peering_descriptor[1].get(
'cidr_overrides',
list_vpc_cidrs(remote_vpc_id, remote_account_id, remote_region))
LOGGER.info(
f"Inspecting route tables in {account_id} {vpc_id} "
f"{region}, peer: {remote_account_id} {remote_vpc_id} {remote_region}"
)
# Initialise a ec2 client connection
ec2_client = aws_client(account_id, 'ec2', region)
# Get active VPC peering if one exists, else continue
# We want to avoid adding routes for inactive peerings.
filters = [{
'Name': 'tag:peerd_created',
'Values': ['true']
}, {
'Name': 'tag:peerd_environment',
'Values': [metadata['environment']]
}, {
'Name': 'status-code',
'Values': ['active', 'provisioning']
}]
if not (peering := get_vpc_peering(vpc_id, remote_vpc_id, account_id,
region, filters)):
# Since we filter for the peerd environment, remind the user that there could be a peering
# But that it might exist as part of another environment, and thus we won't be touching it.
LOGGER.warning(
f'No active peering between {vpc_id} and {remote_vpc_id} for this environment'
f' {metadata["environment"]}. It may exist as part of another environment.'
)
continue
peering_id = peering['VpcPeeringConnectionId']
# Wait until the peering is active, not provisioning (boto waiter doesn't accept filters for vpc peering api)
# We must wait for active state to install routes, otherwise the peering will be ignored.
# Note, usually this step takes a few seconds, but can sometimes take up to a minute or two in rare cases.
if peering['Status']['Code'] == 'provisioning':
while not ec2_client.describe_vpc_peering_connections(
Filters=[{
'Name': 'status-code',
'Values': ['active']
}, {
'Name': 'vpc-peering-connection-id',
'Values': [peering_id]
}])['VpcPeeringConnections']:
LOGGER.info(
f'Waiting for peering {peering_id} to become active...')
sleep(5)
# Get the route tables for the local vpc relevant to the peering.
# The vpc_route_tables function will only return peerd_eligible:true tables
# Since we will have cases where RTs should not be altered.
if not (route_tables := vpc_route_tables(vpc_id, account_id, region)):
LOGGER.warning(f'No peerd_eligible route tables in VPC {vpc_id}')
continue
def create_vpc_peerings(target_peerings: Sequence, metadata: Mapping,
dryrun: bool) -> None:
"""
Loops through a list of peerings to create them.
Requests, accepts and tags them.
Repairs any half open peerings.
Example target_peerings:
```
[
[
{
"account_id": 415432961280,
"vpc_id": "vpc-e08fb484",
"region": "ap-southeast-2",
"cidr_overrides": [
"10.53.101.0/27"
],
"peering_tags": [
{
"peerd_az_affinity": "0"
}
]
},
{
"account_id": 415432961280,
"vpc_id": "vpc-7a83b81e",
"region": "ap-southeast-2"
}
]
]
```
:param target_peerings: A list of lists representing the requester and accepter for each peering.
:type target_peerings: list
:param metadata: A dictionary with the environment, owner, etc for tagging
:type metadata: list
"""
pending_acceptance_peerings = []
for peering_descriptor in target_peerings:
# Unpack some common variables
account_id = peering_descriptor[0]['account_id']
vpc_id = peering_descriptor[0]['vpc_id']
region = peering_descriptor[0]['region']
local_tags = peering_descriptor[0].get('peering_tags', {})
remote_account_id = peering_descriptor[1]['account_id']
remote_vpc_id = peering_descriptor[1]['vpc_id']
remote_region = peering_descriptor[1]['region']
remote_tags = peering_descriptor[1].get('peering_tags', {})
# Create a VPC peering request
try:
ec2_client = aws_client(account_id, 'ec2', region)
# If the peering doesn't exist, create it
if not (peering := get_vpc_peering(vpc_id, remote_vpc_id,
account_id, region)):
LOGGER.info(
f"Creating peering request between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
)
try:
ec2_peering_response = ec2_client.create_vpc_peering_connection(
VpcId=vpc_id,
PeerVpcId=remote_vpc_id,
PeerOwnerId=remote_account_id,
PeerRegion=remote_region,
DryRun=dryrun)['VpcPeeringConnection']
except ClientError as err:
if err.response['Error']['Code'] == 'DryRunOperation':
continue
raise
peering_id = ec2_peering_response['VpcPeeringConnectionId']
# Wait for the vpc peering to exist before moving on
LOGGER.info(f'Waiting for peering {peering_id} to exist...')
ec2_client.get_waiter('vpc_peering_connection_exists').wait(
VpcPeeringConnectionIds=[peering_id],
WaiterConfig={'Delay': 5})
# If the peering exists and is active, do nothing.
elif peering['Status']['Code'] == 'active':
LOGGER.info(
f"Active peering {peering['VpcPeeringConnectionId']} between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
)
continue
# If the peering is pending acceptance move to tagging and acceptance
# Only the remote account can accept the VPC peering.
elif peering['Status']['Code'] == 'pending-acceptance' and peering[
'RequesterVpcInfo']['VpcId'] == vpc_id:
peering_id = peering['VpcPeeringConnectionId']
LOGGER.warning(
f"Pending-Acceptance peering {peering_id} between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}. Will attempt recovery."
)
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
)
continue
# If the peering is pending acceptance move to tagging and acceptance
# Only the remote account can accept the VPC peering.
elif peering['Status']['Code'] == 'pending-acceptance' and peering[
'RequesterVpcInfo']['VpcId'] == vpc_id:
peering_id = peering['VpcPeeringConnectionId']
LOGGER.warning(
f"Pending-Acceptance peering {peering_id} between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}. Will attempt recovery."
)
# We're in some weird state and need to report to a human
else:
LOGGER.warning(
f"Peering between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
f" is in state {peering['Status']['Code']}.")
continue
# Tag the VPC Peering
tags = {
'Name':
f'peerd peering to {remote_account_id} {remote_vpc_id} {remote_region}',
'resource_owner': metadata['resource_owner'],
'business_unit': metadata['business_unit'],
'service_name': metadata['service_name'],
'peerd_created': 'true',
'peerd_support': metadata['support'],
'peerd_datetime': str(datetime.now()),
'peerd_role': 'requester',
'peerd_environment': metadata['environment']
}
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
)
continue
# If the peering is pending acceptance move to tagging and acceptance
# Only the remote account can accept the VPC peering.
elif peering['Status']['Code'] == 'pending-acceptance' and peering[
'RequesterVpcInfo']['VpcId'] == vpc_id:
peerding_id = peering['VpcPeeringConnectionId']
LOGGER.warning(
f"Pending peering between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}. Will attempt recovery."
)
# We're in some weird state and need to report to a human
else:
LOGGER.warning(
f"Peering between {account_id} {vpc_id} {region}"
f" and {remote_account_id} {remote_vpc_id} {remote_region}"
f" is in state {peering['Status']['Code']}.")
continue
# Tag the VPC Peering
tags = {
'Name':
f'peerd peering to {remote_account_id} {remote_vpc_id} {remote_region}',
'resource_owner': metadata['resource_owner'],
'business_unit': metadata['business_unit'],
'service_name': metadata['service_name'],
'peerd_created': 'true',
'peerd_support': metadata['support'],
'peerd_datetime': str(datetime.now()),
'peerd_role': 'requester',
'peerd_environment': metadata['environment']
}
