Rasmus
08/01/2025, 6:48 AMMarvin
08/01/2025, 6:48 AMMarvin
08/01/2025, 6:49 AMPREFECT_CLIENT_CUSTOM_HEADERS
exists as a configuration option, it's not primarily designed as a security feature for self-hosted Prefect servers. If your goal is to secure your self-hosted Prefect server, there are more robust and recommended approaches you should consider first.
Here are the recommended security practices for a self-hosted Prefect server:
1. Basic Authentication
- Enable basic authentication for your Prefect server
- Set up API keys for client authentication
- Configure through environment variables:
bash
PREFECT_SERVER_API_KEY_REQUIRED=true
PREFECT_API_KEY=your-secure-api-key
2. TLS/HTTPS
- Ensure your server uses TLS (minimum version 1.2)
- Set up proper SSL certificates
- Configure through a reverse proxy like nginx
3. Secure Storage
- Use secure storage solutions for credentials (Kubernetes Secrets, HashiCorp Vault, etc.)
- Implement proper environment variable management
- Avoid storing sensitive information in plain text
If you still specifically need to use PREFECT_CLIENT_CUSTOM_HEADERS
, it can be configured to add custom HTTP headers to requests made by the Prefect client to your server. However, this should be considered an additional layer rather than a primary security measure. You can set it like this:
bash
PREFECT_CLIENT_CUSTOM_HEADERS='{"Custom-Auth-Header": "your-token", "Organization-ID": "your-org"}'
For proper security, I strongly recommend focusing on the core security features mentioned above. You can find more detailed information about Prefect security settings in the official documentation.
Would you like me to elaborate on any of these security measures in more detail? Or do you have a specific use case for PREFECT_CLIENT_CUSTOM_HEADERS
that you'd like to discuss?Rasmus
08/01/2025, 6:51 AMMarvin
08/01/2025, 6:51 AMMarvin
08/01/2025, 6:53 AMbash
PREFECT_SERVER_API_KEY_REQUIRED=true
PREFECT_API_KEY=your-secure-api-key
2. Custom Headers Layer
Add custom headers as an additional security check:
bash
PREFECT_CLIENT_CUSTOM_HEADERS='{"X-Custom-Auth-Token": "your-secret-token", "X-Organization-ID": "your-org-id"}'
3. Nginx Reverse Proxy Configuration
Configure your reverse proxy (e.g., Nginx) to validate these headers:
nginx
server {
listen 443 ssl;
server_name <http://your-prefect-server.com|your-prefect-server.com>;
# SSL configuration here...
location / {
# Deny if custom headers are missing or incorrect
if ($http_x_custom_auth_token != "your-secret-token") {
return 403;
}
if ($http_x_organization_id != "your-org-id") {
return 403;
}
proxy_pass <http://your-prefect-server:4200;>
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
# ... other proxy settings
}
}
4. Implementation Strategy
To prevent unauthorized access and deployments:
a) Server-side Validation:
- Configure your reverse proxy to validate all custom headers before requests reach the Prefect server
- Implement rate limiting and request validation
- Enable CSRF protection
b) Client-side Configuration:
- All clients (workers, deployment creators) must have both:
bash
# Basic auth
PREFECT_API_KEY=your-secure-api-key
# Custom headers
PREFECT_CLIENT_CUSTOM_HEADERS='{"X-Custom-Auth-Token": "your-secret-token", "X-Organization-ID": "your-org-id"}'
c) Secure Distribution of Credentials:
- Store credentials in secure vaults (e.g., HashiCorp Vault, Kubernetes Secrets)
- Use different tokens for different environments/teams
- Regularly rotate tokens and API keys
5. Security Benefits
This multi-layered approach provides:
- Double Authentication: Requests must pass both basic auth and custom header validation
- Request Origin Validation: Custom headers can help verify request sources
- Granular Access Control: Different teams/environments can have different header values
- Additional Attack Prevention: Headers can include timestamps or nonces to prevent replay attacks
6. Monitoring and Maintenance
To maintain security:
- Monitor failed authentication attempts in your logs
- Regularly rotate all tokens and API keys
- Audit access patterns periodically
- Keep track of all clients with valid credentials
7. Important Considerations
- Custom headers are transmitted with every request, so ensure they're always over HTTPS
- Headers can be spoofed, which is why they should be used in combination with basic auth, not as the sole security measure
- Consider implementing request signing for even more security
- Monitor for any suspicious patterns in access logs
Would you like me to elaborate on any of these aspects or provide more specific details about implementing any part of this security setup?
Remember that while custom headers add an extra layer of security, they should be part of a comprehensive security strategy that includes proper network security, regular security audits, and following security best practices for your infrastructure as a whole.Rasmus
08/01/2025, 7:04 AMMarvin
08/01/2025, 7:04 AMMarvin
08/01/2025, 7:05 AMName: PREFECT_CLIENT_CUSTOM_HEADERS
Value: {"X-Custom-Auth-Token": "your-secret-token", "X-Organization-ID": "your-org-id"}
b) Using gcloud CLI:
bash
gcloud run deploy your-worker-service \
--image your-worker-image \
--set-env-vars "PREFECT_CLIENT_CUSTOM_HEADERS={'X-Custom-Auth-Token':'your-secret-token','X-Organization-ID':'your-org-id'}"
2. Configure Your Deployments
For deployments to use the same headers when communicating with your Prefect server, you need to set the environment variables in your deployment configuration. Here's how:
a) If using a deployment YAML file:
yaml
deployments:
- name: your-deployment
flow_name: your-flow
work_pool_name: your-work-pool
work_queue_name: default
tags: []
schedule: null
variables:
env:
PREFECT_CLIENT_CUSTOM_HEADERS: '{"X-Custom-Auth-Token":"your-secret-token","X-Organization-ID":"your-org-id"}'
b) If creating deployments programmatically:
python
from prefect import flow
from prefect.deployments import Deployment
@flow
def your_flow():
# your flow code here
pass
deployment = Deployment.build_from_flow(
flow=your_flow,
name="your-deployment",
work_pool_name="your-work-pool",
variables={
"env": {
"PREFECT_CLIENT_CUSTOM_HEADERS": '{"X-Custom-Auth-Token":"your-secret-token","X-Organization-ID":"your-org-id"}'
}
}
)
deployment.apply()
3. Verify Configuration
To verify your headers are being set correctly:
a) Check your worker logs in Cloud Run to ensure the environment variable is present
b) You can add a simple test in your flow:
python
from prefect import flow
import os
@flow
def test_headers():
headers = os.getenv("PREFECT_CLIENT_CUSTOM_HEADERS")
print(f"Current headers: {headers}")
return headers
if __name__ == "__main__":
test_headers()
4. Security Best Practices
When working with custom headers in Cloud Run:
- Use Google Cloud Secret Manager to store sensitive header values
- Reference secrets in your Cloud Run configuration:
bash
gcloud run deploy your-worker-service \
--image your-worker-image \
--set-secrets "PREFECT_CLIENT_CUSTOM_HEADERS=custom-headers:latest"
- Regularly rotate your header values
- Use different header values for different environments (dev/staging/prod)
5. Troubleshooting
If your headers aren't working:
- Verify the JSON formatting in your environment variable is correct
- Check Cloud Run logs for any environment variable parsing errors
- Ensure the headers match exactly what your server is expecting
- Verify the environment variables are being passed correctly to your worker
Would you like me to elaborate on any of these aspects or provide more specific details about any part of the configuration? Also, are you using any specific authentication method with your Cloud Run service that might need to be considered in this setup?Rasmus
08/01/2025, 7:06 AMMarvin
08/01/2025, 7:06 AMMarvin
08/01/2025, 7:07 AMPREFECT_CLIENT_CUSTOM_HEADERS
on the worker, not on both the worker and deployments. Here's why:
1. Worker Role:
- The worker is the component that actually makes API calls to your Prefect server
- It handles all communication between your flows and the Prefect server
- The worker needs the headers to authenticate its API calls
2. Deployment Role:
- Deployments are metadata configurations that describe how to run your flow
- They don't make API calls themselves
- The worker uses the deployment configuration to execute the flow
Therefore, in your Google Cloud Run setup:
✅ DO set on the worker:
bash
# In your Cloud Run service configuration
PREFECT_CLIENT_CUSTOM_HEADERS='{"X-Custom-Auth-Token": "your-secret-token", "X-Organization-ID": "your-org-id"}'
❌ NOT needed in deployments:
- You don't need to include the custom headers in your deployment configuration
- The worker's headers will be used for all API calls
This simplifies your setup and maintains better security by keeping the custom header configuration centralized at the worker level. The worker will use these headers for all API calls it makes on behalf of any deployment it processes.
Would you like me to provide more details about how to verify the headers are working correctly on your Cloud Run worker?Rasmus
08/01/2025, 7:09 AMMarvin
08/01/2025, 7:09 AMMarvin
08/01/2025, 7:10 AMbash
# On your Prefect server
PREFECT_SERVER_API_KEY_REQUIRED=true
b) Deployment Creation Security
- Restrict who can create deployments using API keys:
bash
# Required for deployment creation
PREFECT_API_KEY=your-deployment-creation-key
c) Worker Authentication
bash
# On your Cloud Run worker
PREFECT_API_KEY=your-worker-key
PREFECT_CLIENT_CUSTOM_HEADERS='{"X-Custom-Auth-Token": "your-secret-token"}'
d) Work Pool Security
bash
# Create a work pool with restricted access
prefect work-pool create "secure-pool" \
--type cloud-run \
--base-job-template '{"credentials": "encrypted-credentials"}' \
--concurrency-limit 10
3. Implementation Best Practices
a) Use Different API Keys:
- One for deployment creation
- Another for worker execution
- Different keys for different environments
b) Implement Work Pool ACLs:
python
from prefect.client.cloud import get_cloud_client
from prefect.client.schemas.objects import WorkPool
client = get_cloud_client()
work_pool = client.read_work_pool("secure-pool")
# Set specific permissions
client.set_work_pool_access_policy(
work_pool_name="secure-pool",
access_policy={
"allowed_users": ["<mailto:user1@company.com|user1@company.com>"],
"allowed_teams": ["team-id-1"]
}
)
c) Secure Your Cloud Run Service:
bash
# Deploy with strict IAM policies
gcloud run deploy your-worker \
--image your-image \
--service-account <mailto:restricted-sa@project.iam.gserviceaccount.com|restricted-sa@project.iam.gserviceaccount.com> \
--ingress internal \
--no-allow-unauthenticated
4. Monitoring and Auditing
Implement monitoring to detect suspicious activities:
- Log all deployment creation attempts
- Monitor worker execution patterns
- Set up alerts for unusual activities
Example monitoring setup:
python
from prefect import flow
from prefect.logging import get_run_logger
@flow
def secure_flow():
logger = get_run_logger()
<http://logger.info|logger.info>("Flow execution started")
# Add audit logging
<http://logger.info|logger.info>(f"Execution context: {get_execution_context()}")
5. Regular Security Checks
Implement a security routine:
- Rotate API keys regularly
- Audit work pool permissions
- Review deployment configurations
- Monitor Cloud Run service logs
Would you like me to elaborate on any of these security measures or provide more specific implementation details for your setup? Also, are you using any specific Cloud Run security features that we should integrate into this security model?
Remember: Security should be implemented in layers, and no single security measure (like custom headers or basic auth alone) should be relied upon exclusively.Rasmus
08/01/2025, 7:20 AMMarvin
08/01/2025, 7:20 AMMarvin
08/01/2025, 7:22 AMyaml
deployments:
- name: your-deployment
version: null
tags: []
description: null
schedule: null
flow_name: your-flow
entrypoint: flow.py:your_flow
parameters: {}
work_pool:
name: your-work-pool
work_queue_name: default
variables:
env:
PREFECT_CLIENT_CUSTOM_HEADERS: '{"X-Custom-Auth-Token":"your-secret-token","X-Organization-ID":"your-org-id"}'
2. Using Python Deployment Configuration
python
from prefect import flow
from prefect.deployments import Deployment
@flow
def your_flow():
pass
deployment = Deployment.build_from_flow(
flow=your_flow,
name="your-deployment",
work_pool_name="your-work-pool",
variables={
"env": {
"PREFECT_CLIENT_CUSTOM_HEADERS": '{"X-Custom-Auth-Token":"your-secret-token","X-Organization-ID":"your-org-id"}'
}
}
)
deployment.apply()
3. For Cloud Run Specifically
python
from prefect.deployments import Deployment
from prefect.infrastructure.container import Container
container_infrastructure = Container(
env={
"PREFECT_CLIENT_CUSTOM_HEADERS": '{"X-Custom-Auth-Token":"your-secret-token","X-Organization-ID":"your-org-id"}'
},
image="your-container-image:tag"
)
deployment = Deployment.build_from_flow(
flow=your_flow,
name="your-deployment",
infrastructure=container_infrastructure,
work_pool_name="your-cloud-run-pool"
)
Advantages of this Approach:
1. Isolation: Each deployment has its own headers
2. Granular Control: Different deployments can use different headers
3. Security Boundaries: Compromising one deployment doesn't compromise others
4. Easier Rotation: Can rotate credentials for specific deployments
Security Considerations:
1. Secret Management:
python
# Use Prefect secrets for storing headers
from prefect.blocks.system import Secret
secret_block = Secret.load("custom-headers")
headers = secret_block.get()
deployment = Deployment.build_from_flow(
flow=your_flow,
variables={
"env": {
"PREFECT_CLIENT_CUSTOM_HEADERS": headers
}
}
)
2. Environment-Specific Headers:
python
# Different headers for different environments
headers = {
"dev": {"X-Custom-Auth-Token": "dev-token"},
"prod": {"X-Custom-Auth-Token": "prod-token"}
}
deployment = Deployment.build_from_flow(
flow=your_flow,
variables={
"env": {
"PREFECT_CLIENT_CUSTOM_HEADERS": headers[current_env]
}
}
)
Best Practices:
1. Use Secret Management:
- Store headers in secret management systems
- Use environment-specific secrets
- Rotate secrets regularly
2. Audit and Monitoring:
python
@flow
def audited_flow():
from prefect import get_run_logger
logger = get_run_logger()
# Log (securely) when headers are used
<http://logger.info|logger.info>("Flow execution with custom headers initiated")
# Your flow logic here
3. Version Control:
- Keep deployment configurations in version control
- Use different header values for different branches/environments
- Document header usage and rotation procedures
Would you like me to elaborate on any of these aspects or provide more specific examples for your use case? Also, are you using any specific secret management solution in your Cloud Run environment that we should incorporate into this setup?Rasmus
08/01/2025, 7:24 AMMarvin
08/01/2025, 7:24 AMMarvin
08/01/2025, 7:25 AMbash
pip install prefect-gcp[secret-manager]
2. Create a GCP Credentials Block:
python
from prefect_gcp import GcpCredentials
# Create this once and reference it in your flows
gcp_creds = GcpCredentials(
service_account_info={} # Leave empty to use default credentials
).save("gcp-creds", overwrite=True)
3. Create a Flow that Sets Headers at Runtime:
python
from prefect import flow, task
from prefect_gcp import GcpCredentials
import json
import os
@task
def get_custom_headers():
# Load GCP credentials
gcp_creds = GcpCredentials.load("gcp-creds")
# Get secret from Secret Manager
secret_value = gcp_creds.get_secret(
secret_name="custom-headers",
project="your-project-id"
)
# Parse the secret value (assuming it's stored as JSON)
headers = json.loads(secret_value)
# Set the environment variable
os.environ["PREFECT_CLIENT_CUSTOM_HEADERS"] = json.dumps(headers)
return headers
@flow
def your_flow():
# This will set the headers at the start of the flow
headers = get_custom_headers()
# Your flow logic here
print(f"Using custom headers: {headers}")
4. Create the Deployment:
python
from prefect.deployments import Deployment
deployment = Deployment.build_from_flow(
flow=your_flow,
name="secure-deployment",
work_pool_name="your-cloud-run-pool",
variables={
"env": {
# These environment variables will be available to the container
"GOOGLE_CLOUD_PROJECT": "your-project-id",
# Add any other needed environment variables
}
}
)
deployment.apply()
5. Store Your Headers in Secret Manager:
python
from prefect_gcp import GcpCredentials
# Example of storing headers in Secret Manager
headers = {
"X-Custom-Auth-Token": "your-secret-token",
"X-Organization-ID": "your-org-id"
}
gcp_creds = GcpCredentials.load("gcp-creds")
gcp_creds.create_secret(
secret_name="custom-headers",
secret_value=json.dumps(headers),
project="your-project-id"
)
6. For Better Security, Use a Task to Manage Headers:
python
from prefect import flow, task
from prefect_gcp import GcpCredentials
from contextlib import contextmanager
import json
import os
@contextmanager
def temporary_headers():
"""Context manager to handle header cleanup"""
try:
headers = get_custom_headers()
yield headers
finally:
# Clean up the environment variable after use
if "PREFECT_CLIENT_CUSTOM_HEADERS" in os.environ:
del os.environ["PREFECT_CLIENT_CUSTOM_HEADERS"]
@flow
def secure_flow():
with temporary_headers() as headers:
# Your flow logic here
print(f"Using custom headers: {headers}")
# Headers will be automatically cleaned up after this block
7. For Production Use, Add Error Handling:
python
from prefect import flow, task
from prefect.logging import get_run_logger
from prefect_gcp.exceptions import GcpError
@task(retries=3, retry_delay_seconds=60)
def get_custom_headers():
logger = get_run_logger()
try:
gcp_creds = GcpCredentials.load("gcp-creds")
secret_value = gcp_creds.get_secret(
secret_name="custom-headers",
project="your-project-id"
)
headers = json.loads(secret_value)
os.environ["PREFECT_CLIENT_CUSTOM_HEADERS"] = json.dumps(headers)
return headers
except GcpError as e:
logger.error(f"Failed to retrieve headers from Secret Manager: {e}")
raise
except json.JSONDecodeError as e:
logger.error(f"Invalid header format in secret: {e}")
raise
This approach provides several benefits:
1. Headers are only read when needed
2. Secrets are managed securely in Google Cloud Secret ManagerMarvin
08/01/2025, 7:25 AMRasmus
08/01/2025, 7:26 AMMarvin
08/01/2025, 7:26 AMMarvin
08/01/2025, 7:27 AMprefect.yaml
file. Here's how to set it up to use Google Cloud Secret Manager:
1. First, create your prefect.yaml
:
yaml
# prefect.yaml
deployments:
- name: your-deployment
version: null
tags: []
description: "Deployment with secure headers from Secret Manager"
entrypoint: flow.py:your_flow
parameters: {}
work_pool:
name: your-cloud-run-pool
work_queue_name: default
variables:
env:
# Reference to Secret Manager
PREFECT_CLIENT_CUSTOM_HEADERS: '{{ prefect.blocks.secret_manager.gcp-secret-manager.get_secret("custom-headers") }}'
# Add any other needed environment variables
GOOGLE_CLOUD_PROJECT: "your-project-id"
2. Set up the GCP Secret Manager Block
Create a file called `create_blocks.py`:
python
from prefect_gcp import GcpCredentials
from prefect_gcp.secret_manager import SecretManagerBlock
# Create and save GCP credentials block
credentials = GcpCredentials(
service_account_info={}, # Leave empty to use default credentials
project="your-project-id"
)
credentials.save("gcp-credentials", overwrite=True)
# Create and save Secret Manager block
secret_manager = SecretManagerBlock(
gcp_credentials=credentials,
)
secret_manager.save("gcp-secret-manager", overwrite=True)
3. Store your headers in Secret Manager:
python
from prefect_gcp import GcpCredentials
import json
headers = {
"X-Custom-Auth-Token": "your-secret-token",
"X-Organization-ID": "your-org-id"
}
gcp_creds = GcpCredentials.load("gcp-credentials")
gcp_creds.create_secret(
secret_name="custom-headers",
secret_value=json.dumps(headers),
project="your-project-id"
)
4. Create your flow file (flow.py
):
python
from prefect import flow
@flow
def your_flow():
# Your flow logic here
print("Flow running with secure headers")
if __name__ == "__main__":
your_flow()
5. Deploy your flow:
bash
prefect deploy
6. Alternative YAML Configuration
If you want to use a different secret for different environments, you can use YAML anchors and aliases:
yaml
# prefect.yaml
variables: &base-variables
env:
GOOGLE_CLOUD_PROJECT: "your-project-id"
deployments:
- name: dev-deployment
entrypoint: flow.py:your_flow
work_pool:
name: dev-pool
variables:
<<: *base-variables
env:
PREFECT_CLIENT_CUSTOM_HEADERS: '{{ prefect.blocks.secret_manager.gcp-secret-manager.get_secret("dev-custom-headers") }}'
- name: prod-deployment
entrypoint: flow.py:your_flow
work_pool:
name: prod-pool
variables:
<<: *base-variables
env:
PREFECT_CLIENT_CUSTOM_HEADERS: '{{ prefect.blocks.secret_manager.gcp-secret-manager.get_secret("prod-custom-headers") }}'
7. Using with Different Secret Types
You can also use different types of secrets depending on your environment:
yaml
# prefect.yaml
deployments:
- name: your-deployment
variables:
env:
# For development (using a Prefect Secret block)
PREFECT_CLIENT_CUSTOM_HEADERS: '{{ prefect.blocks.secret.dev-headers.get() }}'
# For production (using GCP Secret Manager)
# PREFECT_CLIENT_CUSTOM_HEADERS: '{{ prefect.blocks.secret_manager.gcp-secret-manager.get_secret("prod-headers") }}'
8. Prerequisites:
bash
# Install required packages
pip install prefect-gcp[secret-manager]
# Run your block creation script
python create_blocks.py
This approach offers several benefits:
1. Configuration is declarative and version-controlled
2. Secrets are managed externally in Google Cloud Secret Manager
3. Different environments can use different secrets
4. No runtime code needed to fetch secrets
5. Easy to update secrets without changing deployment configurationMarvin
08/01/2025, 7:27 AM