FeatBit Agent

The FeatBit Agent is a lightweight .NET application designed to run within your infrastructure. It handles all connections to the FeatBit platform, fetches all of your flag and segment data on startup, caches it, and delivering updates to connected downstream SDKs.

Rather than every client/server connecting directly to the FeatBit platform and streaming changes, they will connect directly to your installed agent to receive any flag updates. The agent can support connecting to multiple environments across different projects for your account, making it a 1:1 replacement for a direct connection.

Use Cases

You may consider setting up the FeatBit Agent in the following scenarios:

• Air-gapped environments: You may be required to operate in environments without internet connectivity. In this situation, running the FeatBit Agent in offline mode provides the capabilities of FeatBit without using external services.
• Reducing outbound connections: With the default configuration, each SDK instance you run will reach out to the FeatBit to fetch all the initial flag data, then maintain an outbound streaming connection to receive any updates you make to that environment. Use the FeatBit agent so your servers can connect directly to hosts in your own data center, instead of connecting directly to FeatBit's streaming API.
• Security and Privacy: In environments with strict security protocols, your application might be restricted from establishing third-party connections. By deploying the FeatBit Agent within your customers' own environments, you can overcome this limitation. Since the agent operates locally, all user information will remain within your customers' environments.

Installation

Note Before diving into the FeatBit Agent installation, you should have a good understanding of what a relay proxy is.

Download

To begin, download the FeatBit Agent from the GitHub releases page to your hosting server.

# Choose your desired version, here we use linux-x64 for example
wget https://github.com/featbit/featbit-agent/releases/download/v1.0.1/featbit_agent_linux-x64_1.0.1.tar.gz

Once the download is complete, perform a quick test to verify that Featbit Agent can run on your machine.

tar -xvzf featbit_agent_linux-x64_1.0.1.tar.gz --one-top-level=featbit-agent
cd featbit-agent

# Run agent from command line
# If the Api file is not executable, Use 'chmod +x Api' to allow execution of the executable file
./Api --urls "http://localhost:6100"

If everything is fine, you should see the following output:

...
info: Microsoft.Hosting.Lifetime[14]
      Now listening on: http://localhost:6100
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Production
info: Microsoft.Hosting.Lifetime[0]
      Content root path: /home/ubuntu/featbit-agent/

Run As A Service (Using Systemd on Linux)

We need to set up a process manager that starts the agent when requests arrive and restarts the agent after it crashes or the server reboots. Here we use systemd for example.

Create the service file

Create the service definition file using the following command:

sed "s,EXTRACTION_FOLDER,$PWD," featbit-agent.service.template > featbit-agent.service
sudo mv featbit-agent.service /etc/systemd/system/featbit-agent.service

Configure the agent

Open the service file for editing

sudo vi /etc/systemd/system/featbit-agent.service

Inside the file, locate the following configuration options and set them according to your requirements:

• (Mandatory) User: Configure the user for running the service.

  # Configure the user for running the service
  # An example value: ubuntu
  User=your-user-name

• (Mandatory) ApiKey: Get an agent key here

  # Check the documentation here to obtain your agent key: https://docs.featbit.co/relay-proxy/relay-proxy#create-a-relay-proxy-configuration
  # An example value: rp-MzM3OTE5MTk0Njg2MQcuGyUHGX90WZvs9RbpZgug
  Environment=ApiKey=your-api-key

• (Optional) ASPNETCORE_URLS: If you want to change the URLs that the FeatBit Agent listen on (defaults to http://*:6100) for request, you need to set the below configuration:

  # Configure the URLs that the FeatBit Agent should listen on for requests.
  # Defaults to http://*:6100
  # An example value: http://*:5000;http://localhost:5001;https://hostname:5002
  # For more details, please check the documentation at: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host?view=aspnetcore-6.0#server-urls
  Environment=ASPNETCORE_URLS=http://*:6100

Save the file after making the necessary configurations.

Start the service and check its status

Now, start the agent service and check its status:

sudo systemctl start featbit-agent.service
sudo systemctl status featbit-agent.service

If everything is fine, you should see the following output:

● featbit-agent.service - The FeatBit Agent Service
     Loaded: loaded (/etc/systemd/system/featbit-agent.service; disabled; vendor preset: enabled)
     Active: active (running) since Thu 2023-06-15 03:35:26 UTC; 1h 40min ago
   Main PID: 2321 (Api)
      Tasks: 14 (limit: 1141)
     Memory: 31.9M
        CPU: 2.814s
     CGroup: /system.slice/featbit-agent.service
             └─2321 /home/ubuntu/featbit-agent/Api

Jun 15 03:35:26 ip-172-31-37-23 systemd[1]: Started The FeatBit Agent Service.
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]: info: Microsoft.Hosting.Lifetime[14]
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]:       Now listening on: http://localhost:6100
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]: info: Microsoft.Hosting.Lifetime[0]
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]:       Application started. Press Ctrl+C to shut down.
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]: info: Microsoft.Hosting.Lifetime[0]
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]:       Hosting environment: Production
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]: info: Microsoft.Hosting.Lifetime[0]
Jun 15 03:35:28 ip-172-31-37-23 featbit-agent[2321]:       Content root path: /home/ubuntu/featbit-agent/

Enable automatic startup

To enable automatic startup of the agent when the OS starts, run the following command:

sudo systemctl enable featbit-agent.service

View logs

Since the FeatBit Agent is managed by systemd, all events and processes are logged to a centralized journal. To view the featbit-agent.service-specific logs, use the following command:

sudo journalctl -fu featbit-agent.service

For further filtering, time options such as --since today, --until 1 hour ago, or a combination of these can reduce the number of entries returned.

sudo journalctl -fu featbit-agent.service --since "2023-06-15" --until "2023-06-15 12:00" 

Health Check

You can run the following command to check if the agent is healthy:

curl http://localhost:6100/health/liveness; echo