cache

Documentation

Overview

Package cache provides shared helpers for cache resource adapters.

Index

• Variables
• type BuildFunc
• type EpochAdvancer
• type FlowOptions
• type FlowResult
  • func RunGenerationFlow(ctx context.Context, ctrl GenerationController, opts FlowOptions) (FlowResult, error)
• type GenerationController
• type RetireFunc
• type VerifyFunc

Variables

var (
	ErrNilController = errors.New("cache: nil generation controller")
	ErrVerifyFailed  = errors.New("cache: generation verify failed")
	ErrAborted       = errors.New("cache: generation aborted")
)

Types

type BuildFunc

type BuildFunc func(ctx context.Context, gen uint64) (map[string]string, error)

BuildFunc populates a reserved generation's seed data.

type EpochAdvancer

type EpochAdvancer interface {
	Advance(id resource.ResourceID, reason string) (resource.EpochAdvance, error)
}

EpochAdvancer optionally advances a registry epoch after activation.

type FlowOptions

type FlowOptions struct {
	ResourceID resource.ResourceID
	Build      BuildFunc
	Verify     VerifyFunc
	Retire     RetireFunc
	Epochs     EpochAdvancer
	DryRun     bool
}

FlowOptions configures a generation rebuild flow.

type FlowResult

type FlowResult struct {
	Previous  uint64                `json:"previous"`
	Reserved  uint64                `json:"reserved"`
	Activated uint64                `json:"activated,omitempty"`
	DryRun    bool                  `json:"dry_run,omitempty"`
	Epoch     resource.EpochAdvance `json:"epoch,omitempty"`
	Retired   bool                  `json:"retired,omitempty"`
}

FlowResult is a sanitized outcome (no cache values).

func RunGenerationFlow

func RunGenerationFlow(ctx context.Context, ctrl GenerationController, opts FlowOptions) (FlowResult, error)

RunGenerationFlow executes reserve → build → verify → activate → epoch → retire. On any failure after reserve, AbortGeneration is called.

type GenerationController

type GenerationController interface {
	BuildGeneration(ctx context.Context) (uint64, error)
	ActivateGeneration(gen uint64, seed map[string]string) error
	AbortGeneration()
	Generation() uint64
}

GenerationController is implemented by memory (and similar) cache adapters.

type RetireFunc

type RetireFunc func(ctx context.Context, previous uint64) error

RetireFunc cleans up prior generation artifacts after activation.

type VerifyFunc

type VerifyFunc func(ctx context.Context, gen uint64, seed map[string]string) error

VerifyFunc checks a built seed before activation.