247 lines
9.3 KiB
Python
Executable File
247 lines
9.3 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Generates Kubernetes secrets based on a provided app name.
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If the `templates` directory contains a secret called `stackspin-{app}-variables`, it
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will check if that secret already exists in the cluster, and if not: generate
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it. It does the same for an `stackspin-{app}-basic-auth` secret that will contain a
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password as well as a htpasswd encoded version of it.
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See https://open.greenhost.net/stackspin/stackspin/-/issues/891 for the
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context why we use this script and not a helm chart to generate secrets.
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usage: `python generate_secrets.py $appName`
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As a special case, `python generate_secrets.py stackspin` will check that the
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`stackspin-cluster-variables` secret exists and that its values do not contain
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problematic characters.
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"""
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import base64
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import crypt
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import os
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import secrets
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import string
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import sys
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import jinja2
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import yaml
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from kubernetes import client, config
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from kubernetes.client import api_client
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from kubernetes.client.exceptions import ApiException
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from kubernetes.utils import create_from_yaml
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from kubernetes.utils.create_from_yaml import FailToCreateError
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# This script gets called with an app name as argument. Most of them need an
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# oauth client in Hydra, but some don't. This list contains the ones that
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# don't.
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APPS_WITHOUT_OAUTH = [
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"single-sign-on",
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"prometheus",
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"alertmanager",
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"suitecrm",
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]
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def main():
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"""Run everything."""
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# Add jinja filters we want to use
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env = jinja2.Environment(
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extensions=["jinja2_base64_filters.Base64Filters"])
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env.filters["generate_password"] = generate_password
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if len(sys.argv) < 2:
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print("Please provide an app name as an argument")
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sys.exit(1)
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app_name = sys.argv[1]
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if app_name == "stackspin":
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# This is a special case: we don't generate new secrets, but verify the
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# validity of the cluster variables (populated from .flux.env).
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verify_cluster_variables()
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else:
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# Create app variables secret
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create_variables_secret(
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app_name, f"stackspin-{app_name}-variables.yaml.jinja", env)
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# Create a secret that contains the oauth variables for Hydra Maester
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if app_name not in APPS_WITHOUT_OAUTH:
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create_variables_secret(
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app_name, "stackspin-oauth-variables.yaml.jinja", env)
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create_basic_auth_secret(app_name, env)
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def verify_cluster_variables():
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data = get_kubernetes_secret_data("stackspin-cluster-variables", "flux-system")
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if data is None:
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raise Exception("Secret stackspin-cluster-variables was not found.")
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message = "In secret stackspin-cluster-variables, key {}, the character {}" \
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" was used which will probably lead to problems, so aborting." \
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" You can update the value by using `kubectl edit secret -n" \
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" flux-system stackspin-cluster-variables`."
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for key, value in data.items():
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decoded_value = base64.b64decode(value).decode("ascii")
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for character in ["\"", "$"]:
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if character in decoded_value:
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raise Exception(message.format(key, character))
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def get_templates_dir():
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"""Returns directory that contains the Jinja templates used to create app secrets."""
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return os.path.join(os.path.dirname(os.path.realpath(__file__)), "templates")
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def create_variables_secret(app_name, variables_filename, env):
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"""Checks if a variables secret for app_name already exists, generates it if necessary."""
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variables_filepath = os.path.join(get_templates_dir(), variables_filename)
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if os.path.exists(variables_filepath):
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# Check if k8s secret already exists, if not, generate it
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with open(variables_filepath, encoding="UTF-8") as template_file:
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lines = template_file.read()
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secret_name, secret_namespace = get_secret_metadata(lines)
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new_secret_dict = yaml.safe_load(
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env.from_string(lines, globals={"app": app_name}).render()
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)
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current_secret_data = get_kubernetes_secret_data(
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secret_name, secret_namespace
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)
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if current_secret_data is None:
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# Create new secret
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update_secret = False
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elif current_secret_data.keys() != new_secret_dict["data"].keys():
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# Update current secret with new keys
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update_secret = True
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print(
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f"Secret {secret_name} in namespace {secret_namespace}"
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" already exists. Merging..."
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)
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# Merge dicts. Values from current_secret_data take precedence
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new_secret_dict["data"] |= current_secret_data
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else:
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# Do Nothing
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print(
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f"Secret {secret_name} in namespace {secret_namespace}"
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" is already in a good state, doing nothing."
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)
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return
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print(
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f"Storing secret {secret_name} in namespace"
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f" {secret_namespace} in cluster."
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)
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store_kubernetes_secret(
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new_secret_dict, secret_namespace, update=update_secret
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)
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else:
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print(
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f"Template {variables_filename} does not exist, no action needed")
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def create_basic_auth_secret(app_name, env):
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"""Checks if a basic auth secret for app_name already exists, generates it if necessary."""
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basic_auth_filename = os.path.join(
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get_templates_dir(), f"stackspin-{app_name}-basic-auth.yaml.jinja"
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)
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if os.path.exists(basic_auth_filename):
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with open(basic_auth_filename, encoding="UTF-8") as template_file:
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lines = template_file.read()
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secret_name, secret_namespace = get_secret_metadata(lines)
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if get_kubernetes_secret_data(secret_name, secret_namespace) is None:
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basic_auth_username = "admin"
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basic_auth_password = generate_password(32)
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basic_auth_htpasswd = gen_htpasswd(
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basic_auth_username, basic_auth_password
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)
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print(
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f"Adding secret {secret_name} in namespace"
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f" {secret_namespace} to cluster."
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)
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template = env.from_string(
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lines,
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globals={
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"pass": basic_auth_password,
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"htpasswd": basic_auth_htpasswd,
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},
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)
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secret_dict = yaml.safe_load(template.render())
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store_kubernetes_secret(secret_dict, secret_namespace)
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else:
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print(
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f"Secret {secret_name} in namespace {secret_namespace}"
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" already exists. Not generating new secrets."
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)
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else:
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print(f"File {basic_auth_filename} does not exist, no action needed")
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def get_secret_metadata(yaml_string):
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"""Returns secret name and namespace from metadata field in a yaml string."""
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secret_dict = yaml.safe_load(yaml_string)
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secret_name = secret_dict["metadata"]["name"]
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# default namespace is flux-system, but other namespace can be
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# provided in secret metadata
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if "namespace" in secret_dict["metadata"]:
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secret_namespace = secret_dict["metadata"]["namespace"]
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else:
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secret_namespace = "flux-system"
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return secret_name, secret_namespace
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def get_kubernetes_secret_data(secret_name, namespace):
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"""Returns the contents of a kubernetes secret or None if the secret does not exist."""
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try:
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secret = API.read_namespaced_secret(secret_name, namespace).data
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except ApiException as ex:
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# 404 is expected when the optional secret does not exist.
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if ex.status != 404:
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raise ex
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return None
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return secret
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def store_kubernetes_secret(secret_dict, namespace, update=False):
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"""Stores either a new secret in the cluster, or updates an existing one."""
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api_client_instance = api_client.ApiClient()
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if update:
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verb = "updated"
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api_response = patch_kubernetes_secret(secret_dict, namespace)
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else:
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verb = "created"
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try:
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api_response = create_from_yaml(
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api_client_instance,
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yaml_objects=[secret_dict],
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namespace=namespace
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)
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except FailToCreateError as ex:
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print(f"Secret not {verb} because of exception {ex}")
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return
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print(f"Secret {verb} with api response: {api_response}")
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def patch_kubernetes_secret(secret_dict, namespace):
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"""Patches secret in the cluster with new data."""
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api_client_instance = api_client.ApiClient()
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api_instance = client.CoreV1Api(api_client_instance)
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name = secret_dict["metadata"]["name"]
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body = {}
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body["data"] = secret_dict["data"]
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return api_instance.patch_namespaced_secret(name, namespace, body)
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def generate_password(length):
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"""Generates a password of "length" characters."""
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length = int(length)
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password = "".join((secrets.choice(string.ascii_letters)
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for i in range(length)))
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return password
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def gen_htpasswd(user, password):
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"""Generate htpasswd entry for user with password."""
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return f"{user}:{crypt.crypt(password, crypt.mksalt(crypt.METHOD_SHA512))}"
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if __name__ == "__main__":
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config.load_kube_config()
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API = client.CoreV1Api()
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main()
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