Glossary

Command

Represents a request to perform an operation as an object or function. Unlike an event it expresses intent, not fact; it provides neither durable queuing nor safe undo by itself.

Common Table Expression

CTE

Common Table Expression

A named auxiliary query in WITH, used by a larger SQL query. It helps structure queries; do not assume automatic materialization or faster execution. Inspect the execution plan.

Common Vulnerabilities and Exposures

CVE

Common Vulnerabilities and Exposures

An identifier for a publicly described vulnerability. Assess whether the component and exploitation conditions exist in your deployment; the identifier alone does not describe all risk.

Composer

PHP dependency manager: composer.json declares requirements and composer.lock pins resolved installation versions.

Composite

Provides a shared contract for individual elements and groups. Define group-operation meaning and whole-tree traversal cost.

Composition

Building behaviour from smaller collaborating parts. It allows dependency changes without extending inheritance hierarchies, but needs clear collaboration contracts.

Concurrency

Multiple tasks make progress over overlapping periods. They need not execute physically at the same instant; results may depend on interleaving.

ConfigMap

Nonsecret Kubernetes configuration. Changing the object does not mean the application has read the new value; behavior depends on injection and refresh mechanisms.

Configuration

Data governing how an application runs in an environment. Validate required settings at startup; configuration should not hold current-customer state or repository-stored secrets.

Connection pool

A bounded set of connections reused by operations. When all are busy, new tasks wait or fail; more threads do not increase database capacity.

Consistency, Availability, Partition tolerance

CAP

Consistency, Availability, Partition tolerance

A distributed-systems result: during a network partition, linearizable consistency and a response to every request at a functioning node cannot both be guaranteed. This concerns behavior during a partition, not an arbitrary choose-two-of-three rule.

Consumer contract

Testable client assumptions about a provider. A test should preserve old-client behaviour rather than updating both sides together and hiding incompatibility.

Container

A process or process group running with isolation and resource controls. A container is not automatically a strong security boundary and usually shares the host kernel.

Container image

A layered artifact containing a filesystem and startup metadata. Removing a secret in a later layer does not remove it from earlier image layers.

Container registry

GHCR

GitHub Container Registry

A service storing and distributing container images. Git source access need not grant image access; the pulling identity needs separate authorization.

Content Delivery Network

CDN

Content Delivery Network

A distributed network delivering and often caching content near users. Incorrect cache rules can expose private responses.

Content Security Policy

CSP

Content Security Policy

A browser policy restricting script and resource sources. It is an additional defense, not a replacement for HTML sanitization or authorization.

Context manager

A mechanism wrapping work with resource setup and cleanup, including on exceptions, such as Python with open.

Continuous delivery or deployment

CD

Continuous Delivery or Continuous Deployment

CI/CD

Continuous Integration / Continuous Delivery or Continuous Deployment

CI integrates changes with checks. Continuous delivery keeps software releasable; continuous deployment automatically deploys changes meeting criteria. Explicitly identify the production-promotion decision.

Continuous integration

CI

Continuous Integration

Frequent integration backed by automated build and test checks. A green pipeline proves only the checks performed, not complete production readiness.

Control plane

Components managing cluster state: API, scheduling and controllers. Workers run workloads. API unavailability is not the same as immediate termination of running containers.

Coroutine

An execution unit that can suspend and resume. Scheduling depends on the runtime; suspension does not automatically move blocking I/O onto a suitable thread.

CORS

CORS

Cross-Origin Resource Sharing

A browser mechanism governing whether script from another origin may read a response. It is not API authorization and does not block every non-browser client.

Coupling

The knowledge and assumptions one module has about another. Access to adapter internals makes adapter changes affect clients.

CPU

CPU

Central Processing Unit

The processor executing program instructions. Analyze CPU load with response time and container limits; a low percentage does not rule out waiting on other resources.

CPython GIL

GIL

Global Interpreter Lock

A lock limiting parallel bytecode execution in CPython builds that use it. Free-threaded builds also exist; do not assign identical constraints to every Python configuration.

CQRS

CQRS

Command Query Responsibility Segregation

Separating the write model from the read model. It can operate in one process and database; separate projections introduce synchronization and rebuilding costs.

CRD

CRD

Custom Resource Definition

Defines a new Kubernetes resource type. A schema alone does not execute behavior; a controller commonly processes instances of that type.

Create, read, update, delete

CRUD

Create, Read, Update, Delete

Basic data creation, reading, updating and deletion operations. Business models often need richer operations and rules than exposing tables directly through HTTP.

Cryptographic hash

SHA

Secure Hash Algorithm

SHA-256

Secure Hash Algorithm, 256-bit

A deterministic digest used for purposes such as integrity checks. A hash alone neither authenticates the author nor encrypts data; anyone knowing the input can compute it.