Source of truth
A source of truth is the authoritative source or representation from which the accepted value or state of information is determined.
Infrastructure as Code, Patterns and Practices: With examples in Python and Terraform
A source of truth is the authoritative representation against which the actual state of a system or resource is reconciled.
- How it is used
- Organizes infrastructure changes around one authoritative, version-controlled configuration that automation reconciles with live resources.
- How deep it goes
- Explains declaration, drift remediation, migration order, imports, state removal, and change history, but defers provider-specific implementation details.
- Examples
- Uses database discovery, network migration, IAM refactoring, Terraform plans, state commands, and descriptive Git commits.
- What you can do after
- Operate/configure infrastructure by reconciling live resources, migrating brownfield environments, and preventing conflicting IaC ownership.
First-Party Data Activation
A single source of truth is an authoritative and consistent data source from which other systems or views derive information.
- How it is used
- Anchors customer data so marketing activation and analytics use consistent facts.
- How deep it goes
- Explains architectural placement, reliability checks, and migration cautions without specifying a data schema or implementation procedure.
- Examples
- Uses shared segmentation labels for campaigns and contrasts central-profile access with separately hosted customer profiles.
- What you can do after
- Evaluate/understand it by checking whether marketing tools share authoritative customer data and can detect discrepancies before campaigns run.
Read how First-Party Data Activation explains source of truth →
Automating API Delivery
A source of truth is the authoritative artifact or system whose state defines the intended state of related artifacts or systems.
- How it is used
- Uses an authoritative OpenAPI definition to coordinate intended API behavior and reduce drift between implementation and published reference.
- How deep it goes
- Walks through updating a definition, regenerating models, protecting custom code, and checking responses; does not treat generated code as complete behavior.
- Examples
- Uses a missing mandatory `keywords` field and a product response extended with two required review fields.
- What you can do after
- Apply it via OpenAPI Generator to regenerate a Spring Boot service from an updated definition while preserving custom controller code.
Effective Platform Engineering
A single source of truth is one authoritative location from which a given set of values or facts is obtained.
- How it is used
- Centralizes secure values for pipelines, deployments, cluster services, and other platform automation.
- How deep it goes
- Explains the operational rationale and retrieval pattern, but stops short of specifying a particular secrets-management architecture.
- Examples
- Uses environment injection, Terraform configuration rendering, pipeline steps, deployment events, and cluster secret services.
- What you can do after
- Operate automation that retrieves secure values consistently and supports simpler credential rotation.
Read how Effective Platform Engineering explains source of truth →
Kafka for Architects
A source of truth is the authoritative system or record from which the canonical value of information is determined.
- How it is used
- Uses authoritative records to reconstruct business state, govern Kafka infrastructure, and coordinate event-schema ownership.
- How deep it goes
- Explains replay and reconciliation workflows, then stops short of making Kafka a general-purpose database.
- Examples
- Uses customer address change logs, order enrichment, Git-managed Kafka configurations, and externally referenced Avro schemas.
- What you can do after
- Designs authoritative state, configuration, or schema ownership while accounting for replay, drift, query, and translation trade-offs.
Terraform in Depth: Infrastructure as Code with Terraform and OpenTofu
A source of truth is the authoritative representation against which the state of a system is evaluated and corrected.
- How it is used
- Centralizes infrastructure deployment and provides one authoritative configuration for team-operated environments.
- How deep it goes
- Defines four GitOps principles and explains drift reconciliation, but stops short of implementation configuration.
- Examples
- Uses shared Git repositories, Alice and Bob’s competing laptops, Terraform configuration, and scheduled drift correction.
- What you can do after
- Operate/configure centralized Terraform deployments from versioned declarations and restore infrastructure that drifts from them.
Knowledge Graphs and LLMs in Action
A source of truth is an authoritative repository or representation from which consistent information is derived.
- How it is used
- Uses knowledge graphs to consolidate fragmented data for decision-making, intelligent systems, and grounded generative AI.
- How deep it goes
- Defines consolidation, contrasts bottom-up and purpose-driven construction, and stops short of detailed normalization procedures.
- Examples
- Uses distributed data sources, heterogeneous databases, graph pattern matching, traversal, and bottom-up KG creation as examples.
- What you can do after
- Evaluate knowledge-graph architectures by their integration strategy, relationship representation, business alignment, and governance implications.
Read how Knowledge Graphs and LLMs in Action explains source of truth →
Authorization in Action
A source of truth is the authoritative system or record from which the correct value of information is obtained.
- How it is used
- Anchors authorization decisions in current, verified identity attributes.
- How deep it goes
- Connects attribute proofing, dynamic evaluation, credential lifetime, and audit logging, without detailing implementation mechanisms.
- Examples
- Uses long-lived credentials retaining outdated attributes as a cause of unauthorized access.
- What you can do after
- Operate authorization systems with verified attributes, dynamic evaluation, and systematic audit feedback.
Related concepts
- repositoryequivalent to · A software repository is an organized storage location or collection of project files and related artifacts, often managed with version history and change tracking.
- append-only systemequivalent to · An append-only system preserves existing data and records changes by adding new entries without modifying or removing prior entries.
- specificationincludes · A specification is a formal or informal description of the required or intended behavior, properties, interfaces, or constraints of a system or component.
- state managementincludes · State management is the practice of organizing, maintaining, and updating information that represents a system’s or process’s condition over time.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.