Dependency Reference

The kindling operator auto-provisions backing services alongside your application. You declare dependencies in the DevStagingEnvironment CR and the operator creates a Pod, Service, and credential Secret for each one, then injects connection-string environment variables into your app container automatically.

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How it works

                                       ┌──────────────────────────────────────┐
     DevStagingEnvironment CR          │  Operator auto-provisions:           │
  ┌──────────────────────────┐         │                                      │
  │ dependencies:            │         │  1. Deployment (postgres:16)         │
  │   - type: postgres       │ ──────▶ │  2. Service   (<name>-postgres)      │
  │     version: "16"        │         │  3. Secret    (<name>-postgres-creds) │
  │   - type: redis          │         │  4. ENV injection: DATABASE_URL      │
  └──────────────────────────┘         │                                      │
                                       │  (same for redis → REDIS_URL, etc.)  │
                                       └──────────────────────────────────────┘

When the operator processes a dependency, it:

1. Looks up the dependency type in its internal registry (image, port, default credentials)
2. Creates a Deployment running the service (e.g. postgres:16)
3. Creates a ClusterIP Service named <cr-name>-<type> (e.g. myapp-postgres)
4. Creates a Secret with all credential key/value pairs
5. Builds a connection URL using the in-cluster DNS name and injects it as an env var into your app container

Your application code just reads the injected env var — no connection strings to hardcode, no service discovery to implement.

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Quick reference table

Type	Env var injected	Connection URL format	Default port
postgres	DATABASE_URL	postgres://devuser:devpass@<name>-postgres:5432/devdb?sslmode=disable	5432
redis	REDIS_URL	redis://<name>-redis:6379/0	6379
mysql	DATABASE_URL	mysql://devuser:devpass@<name>-mysql:3306/devdb	3306
mongodb	MONGO_URL	mongodb://devuser:devpass@<name>-mongodb:27017	27017
rabbitmq	AMQP_URL	amqp://devuser:devpass@<name>-rabbitmq:5672/	5672
minio	S3_ENDPOINT	http://<name>-minio:9000	9000
elasticsearch	ELASTICSEARCH_URL	http://<name>-elasticsearch:9200	9200
kafka	KAFKA_BROKER_URL	<name>-kafka:9092	9092
nats	NATS_URL	nats://<name>-nats:4222	4222
memcached	MEMCACHED_URL	<name>-memcached:11211	11211
cassandra	CASSANDRA_URL	<name>-cassandra:9042	9042
consul	CONSUL_HTTP_ADDR	http://<name>-consul:8500	8500
vault	VAULT_ADDR	http://<name>-vault:8200	8200
influxdb	INFLUXDB_URL	http://devuser:devpass123@<name>-influxdb:8086	8086
jaeger	JAEGER_ENDPOINT	http://<name>-jaeger:16686	16686

<name> is the metadata.name from your DevStagingEnvironment CR.

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Overriding defaults

Every dependency supports these optional fields:

dependencies:
  - type: postgres
    version: "15"              # Image tag (default: latest)
    image: "my-registry/pg:15" # Full image override
    port: 5433                 # Override default port
    envVarName: "PG_URL"       # Override injected env var name
    storageSize: "5Gi"         # PVC size for stateful deps
    env:                       # Override container env vars
      - name: POSTGRES_USER
        value: "custom_user"
      - name: POSTGRES_PASSWORD
        value: "custom_pass"
      - name: POSTGRES_DB
        value: "custom_db"
    resources:                 # CPU/memory limits
      cpuRequest: "100m"
      cpuLimit: "500m"
      memoryRequest: "256Mi"
      memoryLimit: "1Gi"

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Detailed specifications

PostgreSQL

Type: postgres · Port: 5432 · Env: DATABASE_URL

dependencies:
  - type: postgres
    version: "16"

Connection string: postgres://devuser:devpass@<name>-postgres:5432/devdb?sslmode=disable

Code examples

Go:

dsn := os.Getenv("DATABASE_URL")
db, err := sql.Open("postgres", dsn)

Python:

conn = psycopg2.connect(os.environ["DATABASE_URL"])

Node.js:

const pool = new Pool({ connectionString: process.env.DATABASE_URL });

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Redis

Type: redis · Port: 6379 · Env: REDIS_URL

dependencies:
  - type: redis

Connection string: redis://<name>-redis:6379/0

Code examples

Go:

opt, _ := redis.ParseURL(os.Getenv("REDIS_URL"))
client := redis.NewClient(opt)

Python:

r = redis.from_url(os.environ["REDIS_URL"])

Node.js:

const client = createClient({ url: process.env.REDIS_URL });

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MySQL

Type: mysql · Port: 3306 · Env: DATABASE_URL

dependencies:
  - type: mysql
    version: "8.0"

Connection string: mysql://devuser:devpass@<name>-mysql:3306/devdb

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MongoDB

Type: mongodb · Port: 27017 · Env: MONGO_URL

dependencies:
  - type: mongodb

Connection string: mongodb://devuser:devpass@<name>-mongodb:27017

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RabbitMQ

Type: rabbitmq · Port: 5672 · Env: AMQP_URL

dependencies:
  - type: rabbitmq

Connection string: amqp://devuser:devpass@<name>-rabbitmq:5672/

Management UI available on port 15672.

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MinIO (S3-compatible)

Type: minio · Port: 9000 · Env: S3_ENDPOINT, S3_ACCESS_KEY, S3_SECRET_KEY

dependencies:
  - type: minio

Endpoint: http://<name>-minio:9000

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Elasticsearch

Type: elasticsearch · Port: 9200 · Env: ELASTICSEARCH_URL

dependencies:
  - type: elasticsearch

Connection string: http://<name>-elasticsearch:9200

Runs in single-node mode with security disabled for dev.

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Kafka (KRaft mode)

Type: kafka · Port: 9092 · Env: KAFKA_BROKER_URL

dependencies:
  - type: kafka

Broker: <name>-kafka:9092

Runs in KRaft mode (no ZooKeeper required).

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NATS

Type: nats · Port: 4222 · Env: NATS_URL

dependencies:
  - type: nats

Connection string: nats://<name>-nats:4222

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Memcached

Type: memcached · Port: 11211 · Env: MEMCACHED_URL

dependencies:
  - type: memcached

Address: <name>-memcached:11211

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Cassandra

Type: cassandra · Port: 9042 · Env: CASSANDRA_URL

dependencies:
  - type: cassandra

Contact point: <name>-cassandra:9042

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Consul

Type: consul · Port: 8500 · Env: CONSUL_HTTP_ADDR

dependencies:
  - type: consul

Address: http://<name>-consul:8500

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Vault

Type: vault · Port: 8200 · Env: VAULT_ADDR, VAULT_TOKEN

dependencies:
  - type: vault

Address: http://<name>-vault:8200 Dev root token: dev-root-token

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InfluxDB

Type: influxdb · Port: 8086 · Env: INFLUXDB_URL, INFLUXDB_ORG, INFLUXDB_BUCKET

dependencies:
  - type: influxdb

Connection string: http://devuser:devpass123@<name>-influxdb:8086

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Jaeger

Type: jaeger · Port: 16686 · Env: JAEGER_ENDPOINT, OTEL_EXPORTER_OTLP_ENDPOINT

dependencies:
  - type: jaeger

UI endpoint: http://<name>-jaeger:16686 OTLP gRPC: http://<name>-jaeger:4317

tip

Many OpenTelemetry SDKs automatically read OTEL_EXPORTER_OTLP_ENDPOINT from the environment — you may not need to configure it explicitly.

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Multiple dependencies

You can combine any number of dependencies in a single CR:

apiVersion: apps.example.com/v1alpha1
kind: DevStagingEnvironment
metadata:
  name: my-platform
spec:
  deployment:
    image: registry:5000/my-platform:latest
    port: 8080
  service:
    port: 8080
  dependencies:
    - type: postgres
      version: "16"
    - type: redis
    - type: elasticsearch
    - type: kafka
    - type: vault

All five connection env vars (DATABASE_URL, REDIS_URL, ELASTICSEARCH_URL, KAFKA_BROKER_URL, VAULT_ADDR, VAULT_TOKEN) are injected into the app container simultaneously.

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Cross-service dependencies

When service A needs to connect to service B's dependency (e.g. Inventory reading from Orders' Redis queue), use an explicit env override in your deployment spec:

spec:
  deployment:
    image: registry:5000/inventory:latest
    port: 8082
    env:
      - name: REDIS_URL
        value: "redis://myuser-orders-redis:6379/0"
  dependencies:
    - type: mongodb

The env block on the deployment spec lets you reference any service's dependency by its predictable DNS name: <cr-name>-<dep-type>.