docs/articles/enterprise/components/prism.md

Prism

The Prism component powers scenarios and API orchestration.

Networking Details

The default port for the Prism component is TCP port 4050 (HTTP). The port can be configured via configuration (see below).

Prism must be able to receive incoming connections from the following components:

• User Clients (web browser or desktop application)
• App
• API

Prism must be able to make outgoing connections to the following components:

• Exporter

In addition to the above requirements, Prism must be setup with a wildcard subdomain (CNAME DNS record), for example *.prism.example.com. Each Prism instance that is created gets a unique hostname associated with it, for example service1-mock.prism.example.com.

Component Dependencies

Make sure the following components are available before starting the API service:

• PostgreSQL
• Redis
• Gitlab

Installation

Prism can be installed with Docker or via RPM package.

RPM Package

Prior to installing the RPM package, you will need to have the Stoplight package repository installed and configured with your user-specific credentials.

Setting up the Package Repository

You can setup the Stoplight package repo by copying-and-pasting the contents below into a terminal:

# expose credentials to environment first
REPO_USERNAME="myusername"
REPO_PASSWORD="mypassword"

# write credentials to repo file
cat <<EOF | sudo tee /etc/yum.repos.d/stoplight.repo
[stoplight]
name=Stoplight Package Repository
baseurl=https://$REPO_USERNAME:$REPO_PASSWORD@pkg.stoplight.io/rpm
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://pkg.stoplight.io/stoplight.key
EOF

Make sure that the repository credentials are set before issuing the cat command above.

Installing the Prism Package

Once the repository is configured properly, you can install the Pubs component using the command:

sudo yum install prism -y

Docker

To install the Pubs component with Docker, run the command below:

docker pull quay.io/stoplight/prism-multi

Note, if you have not already authenticated with the Stoplight container registry, you will be prompted for credentials.

Configuration

To configure the Prism component, you will need to provide runtime settings and connection details to the Stoplight App, API, and Exporter.

Variables

SL_HOST

The SL_HOST variable is the full URL to the Prism instance.

SL_HOST="http://%sprism.example.com"

Where Prism is being served from the domain prism.example.com. Specifying a port is optional.

Note, the %s preceding the domain is required.

SL_API_HOST

The SL_API_HOST variable is the full URL to the Stoplight API.

SL_API_HOST="http://api.example.com:3030"

SL_EXPORTER_HOST

The SL_EXPORTER_HOST variable is the URL to the Stoplight Exporter.

SL_EXPORTER_HOST="http://exporter.example.com:3031"

ENV_NAME

The ENV_NAME variable is a flag noting the environment level.

ENV_NAME="production"

ENV_NAME should be left as production unless instructed otherwise by the Stoplight Support staff.

MAX_QUEUE_SIZE

The MAX_QUEUE_SIZE variable denotes the internal queue size used to service requests.

MAX_QUEUE_SIZE=500

MAX_QUEUE_SIZE should be left as 500 unless instructed otherwise by the Stoplight Support staff.

MAX_RUNTIME_POOL_SIZE

The MAX_RUNTIME_POOL_SIZE variable denotes the worker pool size used to service requests.

MAX_RUNTIME_POOL_SIZE=15

MAX_RUNTIME_POOL_SIZE should be left as 15 unless instructed otherwise by the Stoplight Support staff.

MAX_WORKERS

The MAX_WORKERS variable denotes the number of worker threads to use when servicing requests.

MAX_WORKERS=25

MAX_WORKERS should be left as 25 unless instructed otherwise by the Stoplight Support staff.

PRISM_LOG_LEVEL

The PRISM_LOG_LEVEL variable denotes the log level of the Prism process.

PRISM_LOG_LEVEL="ERROR"

PRISM_LOG_LEVEL should be left as ERROR unless instructed otherwise by the Stoplight Support staff.

RPM Package

The Prism configuration file is located at the location:

/etc/prism/prism.cfg

Be sure to customize any variables as needed to match your environment before starting the Prism service.

Any changes to the Prism configuration requires a service restart in order to take effect.

Docker

The Prism container can be configured either via file (see the package configuration above) or via environment variables. If you would like to configure Prism via environment variable, use the variable names directly from the Prism configuration above.

To expose variables to the Docker runtime, either write them to a file and use the --env-file argument:

cat <<EOF>prism-env-vars
SL_API_HOST="..."
...
EOF

docker run --env-file prism-env-vars ...

Alternatively, you can expose them one at a time with the -e flag:

docker run -e SL_API_HOST=api.stoplight.example.com ...

Running

RPM Package

To start the Prism server, run the command:

sudo systemctl start prism

Once started, you can see the status of the service using the command:

sudo systemctl status prism

Docker

To start the Prism container, use the command:

docker run \
	--restart on-failure \
	--env-file prism-env-vars \
	-p 4050:4050 \
	quay.io/stoplight/prism-multi:latest

If started properly, the container should be marked with a healthy status after 30 seconds. Use the docker ps command to verify the container was started and is running properly.

Post-install Validations

Once the Prism component is running, you can verify the installation was successful by issuing an HTTP GET request to the /health endpoint:

curl -v localhost:4050/health

Be sure to update the URL above to match your local installation

If Prism was installed and configured properly, you will receive an HTTP 200 response back.