NodeJS and PostgreSQL
score-compose and score-k8s6 minute read
Overview
In this example we will walk you through how you can deploy a NodeJS containerized application using a PostgreSQL database, and this with both score-compose and score-k8s.
flowchart TD
dns[DNS] --> nodejs-workload(NodeJS)
subgraph Workloads
nodejs-workload
end
nodejs-workload-->postgres[(PostgreSQL)]
1. score.yaml
Open your IDE and paste in the following score.yaml file, which describes a simple web server exposed via a DNS that queries a PostgreSQL database on each request. The demo code can be found here.
apiVersion: score.dev/v1b1
metadata:
name: hello-world
containers:
hello-world:
image: .
variables:
PORT: "3000"
MESSAGE: "Hello, World!"
DB_DATABASE: ${resources.db.name}
DB_USER: ${resources.db.username}
DB_PASSWORD: ${resources.db.password}
DB_HOST: ${resources.db.host}
DB_PORT: ${resources.db.port}
service:
ports:
www:
port: 8080
targetPort: 3000
resources:
db:
type: postgres
dns:
type: dns
route:
type: route
params:
host: ${resources.dns.host}
path: /
port: 8080
From here, you can deploy this exact same Score file:
- Either with
score-compose - Or with
score-k8s
2. score-compose
To begin, follow the installation instructions to install the latest version of score-compose.
init
Initialize your current score-compose workspace, run the following command in your terminal:
score-compose init --no-sample
The init command will create the .score-compose directory with the default resource provisioners available.
You can see the resource provisioners available by running this command:
score-compose provisioners list
The Score file example illustrated uses three resource types: postgres, dns and route.
+---------------+-------+------------------+--------------------------------+---------------------------------+
| TYPE | CLASS | PARAMS | OUTPUTS | DESCRIPTION |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| dns | (any) | | host | Outputs a *.localhost domain |
| | | | | as the hostname |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| postgres | (any) | | database, host, name, | Provisions a dedicated |
| | | | password, port, username | database on a shared PostgreSQL |
| | | | | instance |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| route | (any) | host, path, port | | Provisions an Ingress route on |
| | | | | a shared Nginx instance |
+---------------+-------+------------------+--------------------------------+---------------------------------+
generate
Convert the score.yaml file into a runnable compose.yaml, run the following command in your terminal:
score-compose generate score.yaml --image ghcr.io/score-spec/sample-score-app:latest
The generate command will add the input score.yaml workload with a particular container image to the .score-compose/state.yaml state file and generate the output compose.yaml.
If you want to build the container image when this compose.yaml will be deployed, you can run this generate command with the --build parameter instead:
score-compose generate score.yaml --build 'main={"context":".","tags":["sample-score-app:local"]}'
See the generated compose.yaml by running this command:
cat compose.yaml
If you make any modifications to the score.yaml file, run score-compose generate score.yaml to regenerate the output compose.yaml.
resources
Get the information of the resources dependencies of the workload, run the following command:
score-compose resources list
+---------------------------------+--------------------------------+
| UID | OUTPUTS |
+---------------------------------+--------------------------------+
| dns.default#hello-world.dns | host |
+---------------------------------+--------------------------------+
| postgres.default#hello-world.db | database, host, name, |
| | password, port, username |
+---------------------------------+--------------------------------+
| route.default#hello-world.route | |
+---------------------------------+--------------------------------+
At this stage, we can already see the value of the dns resource generated:
score-compose resources get-outputs dns.default#hello-world.dns --format '{{ .host }}'
dnsbcsqnd.localhost
Same for the postgres resource:
score-compose resources get-outputs postgres.default#hello-world.db
{
"database": "db-cHqToKGM",
"host": "pg-l1fFqm",
"name": "db-cHqToKGM",
"password": "REDACTED",
"port": 5432,
"username": "REDACTED"
}
docker compose
Run docker compose up to execute the generated compose.yaml file:
docker compose up -d
[+] Running 7/7
✔ Network nodejs_default Created
✔ Volume "nodejs_pg-Tut8g7-data" Created
✔ Container nodejs-pg-Tut8g7-1 Healthy
✔ Container nodejs-routing-CzbPM2-1 Started
✔ Container nodejs-pg-Tut8g7-init-1 Exited
✔ Container nodejs-wait-for-resources-1 Exited
✔ Container nodejs-hello-world-hello-world-1 Started
docker ps
See the running containers:
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8488aa2fe204 ghcr.io/score-spec/sample-score-app:latest "node index.js" 17 minutes ago Up 17 minutes 3000/tcp nodejs-hello-world-hello-world-1
22c78e726612 mirror.gcr.io/nginx:1-alpine "/docker-entrypoint.…" 17 minutes ago Up 17 minutes 0.0.0.0:8080->80/tcp, [::]:8080->80/tcp nodejs-routing-CzbPM2-1
01cc858a6162 mirror.gcr.io/postgres:17-alpine "docker-entrypoint.s…" 17 minutes ago Up 17 minutes (healthy) 5432/tcp nodejs-pg-Tut8g7-1
curl localhost:8080
Test the running container, run the following command:
curl localhost:8080 -H "Host: dnsbcsqnd.localhost"
Hello, World!
This is an application talking to a PostgreSQL 17.5 database on host pg-Tut8g7, deployed with Score!
PostgreSQL 17.5 on x86_64-pc-linux-musl, compiled by gcc (Alpine 14.2.0) 14.2.0, 64-bit
Congrats! You’ve successfully deploy, with the score-compose implementation, a sample NodeJS containerized workload talking to PostgreSQL and exposed via a DNS. You provisioned them through Docker, without writing the Docker Compose file by yourself.
3. score-k8s
To begin, follow the installation instructions to install the latest version of score-k8s.
init
Initialize your current score-k8s workspace, run the following command in your terminal:
score-k8s init --no-sample
The init command will create the .score-k8s directory with the default resource provisioners available.
You can see the resource provisioners available by running this command:
score-k8s provisioners list
The Score file example illustrated uses three resource types: postgres, dns and route.
+---------------+-------+------------------+--------------------------------+---------------------------------+
| TYPE | CLASS | PARAMS | OUTPUTS | DESCRIPTION |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| dns | (any) | | host | Outputs a *.localhost domain |
| | | | | as the hostname |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| postgres | (any) | | database, host, name, | Provisions a dedicated |
| | | | password, port, username | database on a shared PostgreSQL |
| | | | | instance |
+---------------+-------+------------------+--------------------------------+---------------------------------+
| route | (any) | host, path, port | | Provisions an Ingress route on |
| | | | | a shared Nginx instance |
+---------------+-------+------------------+--------------------------------+---------------------------------+
generate
Convert the score.yaml file into a runnable manifests.yaml, run the following command in your terminal:
score-k8s generate score.yaml --image ghcr.io/score-spec/sample-score-app:latest
The generate command will add the input score.yaml workload with a particular container image to the .score-k8s/state.yaml state file and generate the output manifests.yaml.
See the generated manifests.yaml by running this command:
cat manifests.yaml
If you make any modifications to the score.yaml file, run score-k8s generate score.yaml to regenerate the output manifests.yaml.
resources
Get the information of the resources dependencies of the workload, run the following command:
score-k8s resources list
+---------------------------------+--------------------------------+
| UID | OUTPUTS |
+---------------------------------+--------------------------------+
| dns.default#hello-world.dns | host |
+---------------------------------+--------------------------------+
| postgres.default#hello-world.db | database, host, name, |
| | password, port, username |
+---------------------------------+--------------------------------+
| route.default#hello-world.route | |
+---------------------------------+--------------------------------+
At this stage, we can already see the value of the dns resource generated:
score-k8s resources get-outputs dns.default#hello-world.dns --format '{{ .host }}'
dnsgm0shc.localhost
Same for the postgres resource:
score-k8s resources get-outputs postgres.default#hello-world.db
{
"database": "db-QnPWyXNB",
"host": "pg-Tut8g7",
"name": "db-QnPWyXNB",
"password": "REDACTED",
"port": 5432,
"username": "REDACTED"
}
kubectl apply
Here you will need to have access to a Kubernetes cluster to execute the following commands. You can follow these instructions if you want to set up a Kind cluster.
Run kubectl apply to execute the generated manifests.yaml file:
kubectl apply -f manifests.yaml
secret/pg-hello-world-87af7a15 created
statefulset.apps/pg-hello-world-87af7a15 created
service/pg-hello-world-87af7a15 created
httproute.gateway.networking.k8s.io/route-hello-world-4b82945e created
service/hello-world created
deployment.apps/hello-world created
kubectl get all
See the running containers:
kubectl get all
NAME READY STATUS RESTARTS AGE
pod/hello-world-68cd6f7968-26fh8 1/1 Running 2 (31s ago) 37s
pod/pg-hello-world-87af7a15-0 1/1 Running 0 37s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/hello-world ClusterIP 10.96.250.192 <none> 8080/TCP 37s
service/pg-hello-world-87af7a15 ClusterIP 10.96.231.3 <none> 5432/TCP 37s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/hello-world 1/1 1 1 37s
NAME DESIRED CURRENT READY AGE
replicaset.apps/hello-world-68cd6f7968 1 1 1 37s
NAME READY AGE
statefulset.apps/pg-hello-world-87af7a15 1/1 37s
curl localhost
Test the running container, run the following command:
curl localhost -H "Host: dnsgm0shc.localhost"
Hello, World!
This is an application talking to a PostgreSQL 17.5 database on host pg-Tut8g7, deployed with Score!
PostgreSQL 17.5 on x86_64-pc-linux-musl, compiled by gcc (Alpine 14.2.0) 14.2.0, 64-bit
Congrats! You’ve successfully deploy, with the score-k8s implementation, a sample NodeJS containerized workload talking to PostgreSQL and exposed via a DNS. You provisioned them through kubectl, without writing the Kubernetes manifests file by yourself.
Next steps
- Explore more examples: Check out more examples to dive into further use cases and experiment with different configurations.
- Join the Score community: Connect with fellow Score developers on our CNCF Slack channel or start find your way to contribute to Score.