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Scope system

The scope system is the foundation of the Pull Server's hierarchical parameter merging. It defines how parameter values are organized, prioritized, and associated with managed nodes.

Scope types

A scope type is a category in your organizational hierarchy. Each scope type represents a dimension along which configuration can vary — geography, deployment stage, team, or any other grouping that makes sense for your organization.

Every scope type has:

  • A name that identifies the category (e.g., Region, Environment).
  • A precedence value that determines its position in the merge order. Higher values are applied later and take priority.

Built-in scope types

Scope type Precedence Description
Default 0 Global baseline, always the first
Node ∞ Per-node overrides, always the last

Custom scope types

Create custom scope types to match your organizational structure. Common examples:

Scope type Precedence Example values
Region 10 US-West, US-East, EU-Central
Environment 20 Development, Staging, Production
Team 30 Platform, Security, Application

Scope values

A scope value is a specific instance of a scope type. For the scope type "Region", scope values might be "US-West" and "EU-Central".

Scope values are the identifiers that parameter files are organized under. The Pull Server stores parameter files in a directory structure:

parameters/{ConfigurationName}/{ScopeType}/{ScopeValue}/parameters.yaml

Node tags

Node tags associate a managed node with specific scope values. Each node can have at most one tag per scope type.

For example, a web server in the US West production environment might have:

Scope type Scope value
Region US-West
Environment Production

When the Pull Server merges parameters for this node, it looks up the parameter files for each tagged scope value and applies them in precedence order.

Designing your scope hierarchy

When designing your scope hierarchy, consider:

  • Breadth vs. depth — fewer scope types with more values is simpler to manage than many nested scope types.
  • Precedence order — arrange scope types so that more specific overrides have higher precedence.
  • Team ownership — align scope types with the teams that manage each layer of configuration.