An API gateway needs a deployment configuration before it can expose a backend service to consumers. A declarative configuration states the gateway’s desired operating state—such as routes, authentication, usage plans, rate limits, and logging—without prescribing the commands that create it. section 1.5.5
Write the required property values in a file; a tool or agent reads them and performs the implementation steps. An imperative script instead specifies which commands run and in what order. The declarative approach separates decisions about the required state from the commands needed to achieve it. section 1.5.5 section 9.4.1
For an APIOps deployment:
- Store each environment’s gateway configuration in Git and make updates there rather than through the gateway UI. Version history supports collaboration and auditing; pull requests and CODEOWNERS can control approvals. section 1.5.5 section 9.4.1
- Have an automated agent or deployment pipeline obtain the declared state and apply it. Reconciliation compares actual state with desired state and attempts to correct drift. section 9.4.1
Listing 6.4 Kong API gateway declarative configuration
_format_version: "1.1"
services:
- name: Product_Catalog_API
protocol: http
host: localhost
port: 8080
path: /
routes:
- tags:
- Product Catalog
name: viewProduct
methods:
- GET #1
hosts: #1
- api.acme-pet-supplies.com #1
paths: #1
- /v1/catalog/products/(.+)$ #1
strip_path: false #1
plugins: #1
- name: key-auth #2
config:
key_names:
- x-api-key
consumers:
- username: my_api_consumer
keyauth_credentials:
- key: my_secret_api_key
The Kong YAML provides a concrete configuration: a backend service on port 8080, a GET route constrained by host and path, and key-auth requiring an x-api-key header. section 6.2.2
Check the gateway route
From the Kong configuration directory, run `kong start -c kong.conf`. Request `GET http://localhost:8000/v1/catalog/products/612b4280-b5c0-4ad5-bce7-ede7ab2b80fc` with `Host: api.acme-pet-supplies.com` and `x-api-key: my_secret_api_key`. A product response confirms that the request reached the secured API through the gateway. Without the configured Host header, the request will not match this route; consumers must also supply the configured API key. section 6.2.2
