Documentation
¶
Overview ¶
Package projection owns the concrete graph data model types shared by the execution engine, Starlark projection layer, and CLI tools.
Core Types ¶
- Graph: A directed graph of nodes and edges representing work to be done
- Node: A single unit of work with an action to execute
- Edge: A dependency relationship between nodes
Graph Lifecycle ¶
The Graph represents both plans (before execution) and receipts (after execution):
- Before Run(): State is "pending", nodes describe what will happen
- After Run(): State is "executed", nodes describe what happened
- Serialized before execution: "dry-run" or "purchase order"
- Serialized after execution: "receipt"
Index ¶
- Constants
- func FillSlot(node *Node, graph *Graph, slotName string, value starlark.Value) error
- func GenerateNodeID(prefix string, components ...string) string
- func GitStyleChecksum(objectType, basename string, content []byte) string
- func GoToStarlarkValue(v any) (starlark.Value, error)
- func ListToStringSlice(list *starlark.List) []string
- func MakeAttr(name string, fn BuiltinFunc) starlark.Value
- func NoSuchAttrError(receiver, attr string) error
- func StarlarkDictToMap(dict *starlark.Dict) (map[string]any, error)
- func StarlarkListToSlice(list *starlark.List) (any, error)
- func StarlarkValueToGo(v starlark.Value) (any, error)
- func StubAction(name string) any
- type Attempt
- type BackoffStrategy
- type BuiltinFunc
- type Collision
- type Edge
- type Encoder
- type Gather
- type Graph
- type GraphContext
- type GraphState
- type Node
- func (n *Node) ActionName() string
- func (n *Node) GetID() string
- func (n *Node) GetProject() string
- func (n *Node) GetSlot(name string) any
- func (n Node) MarshalJSON() ([]byte, error)
- func (n Node) MarshalYAML() (any, error)
- func (n *Node) RequireStringSlot(name string) (string, error)
- func (n *Node) ResolvedSlots(results map[string]any, proxyCtx ...map[string]any) map[string]any
- func (n *Node) SetSlotImmediate(name string, value any)
- func (n *Node) SetSlotPromise(name, nodeRef, slot string)
- func (n *Node) SetSlotProxy(name, gatherRef, field string)
- func (n *Node) UnmarshalJSON(data []byte) error
- func (n *Node) UnmarshalYAML(value *yaml.Node) error
- type NodeStatus
- type Output
- func (o *Output) Attr(name string) (starlark.Value, error)
- func (o *Output) AttrNames() []string
- func (o *Output) DependOn(consumer *Node)
- func (o *Output) FillSlot(consumer *Node, slotName string)
- func (o *Output) Freeze()
- func (o *Output) Graph() *Graph
- func (o *Output) Hash() (uint32, error)
- func (o *Output) Node() *Node
- func (o *Output) Path() string
- func (o *Output) Slot() string
- func (o *Output) String() string
- func (o *Output) Truth() starlark.Bool
- func (o *Output) Type() string
- type Phase
- type PhaseStatus
- type Platform
- type Receiver
- type RetryPolicy
- type RollbackEntry
- type Signature
- type SlotValue
- type Summary
Constants ¶
const ( AccessImmediate = "immediate" // query only — no graph node AccessPlanned = "planned" // graph node only — no immediate call AccessBoth = "both" // available in both projections )
Access level constants define when a provider method is available.
Variables ¶
This section is empty.
Functions ¶
func FillSlot ¶
FillSlot fills a slot in a node from a Starlark value.
Any slot accepts:
- A promise (Output): creates an edge, value flows at runtime
- A gather (Gather): creates edges from all members (parallel execution)
- An immediate value: stored directly, known at analysis time
func GenerateNodeID ¶
GenerateNodeID creates a unique node ID with the given prefix and components.
func GitStyleChecksum ¶
GitStyleChecksum computes a git-style checksum. Format: SHA256("<type> <basename> <len>\0<content>") Returns format "sha256:<hex>".
func GoToStarlarkValue ¶
GoToStarlarkValue converts a native Go value to a Starlark value.
func ListToStringSlice ¶
ListToStringSlice converts a Starlark list to a Go string slice. Used by generated receivers to convert []string parameters.
func MakeAttr ¶
func MakeAttr(name string, fn BuiltinFunc) starlark.Value
MakeAttr creates a starlark.Builtin from a receiver method.
func NoSuchAttrError ¶
NoSuchAttrError returns an error for an unknown attribute.
func StarlarkDictToMap ¶
StarlarkDictToMap converts a Starlark dict to a Go map[string]any.
func StarlarkListToSlice ¶
StarlarkListToSlice converts a Starlark list to a Go slice. Returns []string if all elements are strings, []any otherwise.
func StarlarkValueToGo ¶
StarlarkValueToGo converts a Starlark value to a native Go value.
func StubAction ¶
StubAction creates a named action stub for testing and receipt deserialization. The stub is not executable — the executor replaces stubs via HydrateGraph.
Types ¶
type Attempt ¶
type Attempt struct {
// Number is the 1-based attempt number.
Number int `json:"number" yaml:"number"`
// Status is "completed" or "failed".
Status string `json:"status" yaml:"status"`
// Error is the error message if the attempt failed.
Error string `json:"error,omitempty" yaml:"error,omitempty"`
// Timestamp is when this attempt completed (RFC3339).
Timestamp string `json:"timestamp" yaml:"timestamp"`
}
Attempt records one execution attempt of a phase.
type BackoffStrategy ¶
type BackoffStrategy string
BackoffStrategy defines how delays increase between retries.
const ( BackoffNone BackoffStrategy = "none" BackoffLinear BackoffStrategy = "linear" BackoffExponential BackoffStrategy = "exponential" )
type BuiltinFunc ¶
type BuiltinFunc func(thread *starlark.Thread, fn *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error)
BuiltinFunc is the signature for builtin function implementations.
type Collision ¶
type Collision struct {
Target string `json:"target" yaml:"target"`
Winner string `json:"winner" yaml:"winner"`
WinnerLayer string `json:"winner_layer,omitempty" yaml:"winner_layer,omitempty"`
WinnerSpecificity int `json:"winner_specificity,omitempty" yaml:"winner_specificity,omitempty"`
Loser string `json:"loser" yaml:"loser"`
LoserLayer string `json:"loser_layer,omitempty" yaml:"loser_layer,omitempty"`
LoserSpecificity int `json:"loser_specificity,omitempty" yaml:"loser_specificity,omitempty"`
}
Collision records a source conflict resolved during tree building (writ-specific).
type Edge ¶
Edge represents a dependency relationship between two nodes. From must complete before To can begin execution.
type Encoder ¶
Encoder is the interface for graph serialization. Both *json.Encoder and *yaml.Encoder satisfy this interface.
type Gather ¶
type Gather struct {
// contains filtered or unexported fields
}
Gather represents a collection of outputs that can run in parallel. When used as a slot input, it creates edges from ALL members to the consumer, enabling parallel execution of the gathered nodes.
Usage in Starlark:
a = plan.file.copy(src1, dst1) b = plan.file.copy(src2, dst2) c = plan.file.copy(src3, dst3) group = plan.gather(a, b, c) d = plan.whatever(group) # d waits for a, b, c (which run in parallel)
type Graph ¶
type Graph struct {
// Version is the graph format version.
Version string `json:"version" yaml:"version"`
// Tool identifies which tool created this graph ("writ" or "lore").
Tool string `json:"tool" yaml:"tool"`
// Timestamp is when the graph was created/executed.
Timestamp time.Time `json:"timestamp" yaml:"timestamp"`
// State is the execution state (pending, executed, failed).
State GraphState `json:"state" yaml:"state"`
// Platform records the OS and architecture.
Platform Platform `json:"platform" yaml:"platform"`
// Context contains tool-specific metadata.
Context GraphContext `json:"context" yaml:"context"`
// Nodes are the actions to perform/performed.
Nodes []*Node `json:"nodes" yaml:"nodes"`
// Edges are the dependencies between nodes.
Edges []Edge `json:"edges,omitempty" yaml:"edges,omitempty"`
// Phases defines the ordered lifecycle phases (nil for non-phased graphs).
// When present, the executor uses phase-aware execution with retry and rollback.
// When nil, the executor falls back to flat node execution.
Phases []*Phase `json:"phases,omitempty" yaml:"phases,omitempty"`
// Collisions records source conflicts resolved during tree building (writ-specific).
Collisions []Collision `json:"collisions,omitempty" yaml:"collisions,omitempty"`
// Summary contains execution statistics (populated after Run).
Summary Summary `json:"summary,omitempty" yaml:"summary,omitempty"`
// Rollback records compensating actions executed during rollback (populated on failure).
Rollback []RollbackEntry `json:"rollback,omitempty" yaml:"rollback,omitempty"`
// Checksum is the git-style integrity hash.
Checksum string `json:"checksum,omitempty" yaml:"checksum,omitempty"`
// Signature contains the cryptographic signature (optional).
Signature *Signature `json:"signature,omitempty" yaml:"signature,omitempty"`
}
Graph represents an execution graph containing nodes and edges. This is THE graph used by both writ and lore - they differ only in content.
Before Run(): State is "pending", represents the plan After Run(): State is "executed", represents the receipt
func (*Graph) CanonicalContent ¶
CanonicalContent returns the graph serialized as YAML without checksum and signature. This is used for computing checksums and verifying signatures.
func (*Graph) CollectPhaseNodes ¶
CollectPhaseNodes returns the nodes and intra-phase edges for the given phase. Nodes are returned in graph order; edges are filtered to only those between phase-internal nodes.
func (*Graph) ComputeSummary ¶
func (g *Graph) ComputeSummary()
ComputeSummary calculates summary statistics from nodes. For phased graphs, node statuses reflect the phase execution outcome (nodes in rolled-back phases may show as completed from before rollback).
func (*Graph) Filename ¶
Filename returns the standard filename for this graph. Format: "<tool>-<timestamp>.yaml"
type GraphContext ¶
type GraphContext struct {
// SourceRoot is the source directory (writ: repo path, lore: registry cache).
SourceRoot string `json:"source_root,omitempty" yaml:"source_root,omitempty"`
// TargetRoot is the target directory (typically $HOME).
TargetRoot string `json:"target_root,omitempty" yaml:"target_root,omitempty"`
// Projects lists the projects included (writ-specific).
Projects []string `json:"projects,omitempty" yaml:"projects,omitempty"`
// Packages lists the packages included (lore-specific).
Packages []string `json:"packages,omitempty" yaml:"packages,omitempty"`
// Segments contains platform segment values (writ-specific).
Segments map[string]string `json:"segments,omitempty" yaml:"segments,omitempty"`
// Layers lists repository layers used (writ-specific).
Layers []string `json:"layers,omitempty" yaml:"layers,omitempty"`
// Platform is the target platform string (lore-specific, e.g., "Darwin", "Linux.Debian").
TargetPlatform string `json:"target_platform,omitempty" yaml:"target_platform,omitempty"`
// Features enabled for package installation (lore-specific).
Features []string `json:"features,omitempty" yaml:"features,omitempty"`
// Settings for package installation (lore-specific).
Settings map[string]string `json:"settings,omitempty" yaml:"settings,omitempty"`
}
GraphContext contains tool-specific metadata stored in the graph. Both writ and lore populate this with their relevant context.
type GraphState ¶
type GraphState string
GraphState represents the execution state of the graph.
const ( StatePending GraphState = "pending" StateExecuted GraphState = "executed" StateFailed GraphState = "failed" )
type Node ¶
type Node struct {
// ID is the unique identifier (typically relative target path or package name).
ID string `json:"id" yaml:"id"`
// Action to perform. Stored as any because the Action interface lives in
// internal/execution. The executor type-asserts before calling Do.
// Serialized as the action name string; deserialized as a stubAction.
Action any `json:"-" yaml:"-"`
// Status of this node: pending, completed, skipped, failed.
Status NodeStatus `json:"status" yaml:"status"`
// Timestamp is when this action completed.
Timestamp string `json:"timestamp,omitempty" yaml:"timestamp,omitempty"`
// Slots holds input values for this node. Each slot can be:
// - Immediate: value known at analysis time
// - Promise: reference to another node's output (creates edge)
Slots map[string]SlotValue `json:"slots,omitempty" yaml:"slots,omitempty"`
// Project this node belongs to.
Project string `json:"project,omitempty" yaml:"project,omitempty"`
// Layer is the repository layer (base, team, personal).
Layer string `json:"layer,omitempty" yaml:"layer,omitempty"`
// Error message if status is failed.
Error string `json:"error,omitempty" yaml:"error,omitempty"`
// Retry is the retry policy for this node (nil = no retry).
Retry *RetryPolicy `json:"retry,omitempty" yaml:"retry,omitempty"`
// Annotations holds extensible metadata (serialized to receipts).
Annotations map[string]string `json:"annotations,omitempty" yaml:"annotations,omitempty"`
}
Node represents a single unit of work in an execution graph.
func (*Node) ActionName ¶
ActionName returns the action name. Works for both live nodes (Action set by executor) and deserialized receipt nodes (stubAction).
func (*Node) GetSlot ¶
GetSlot returns the resolved value of a slot. If the slot is a promise, returns nil (must be resolved by executor).
func (Node) MarshalJSON ¶
MarshalJSON serializes the node with Action as its name string.
func (Node) MarshalYAML ¶
MarshalYAML serializes the node with Action as its name string. Note: we cannot use the nodeJSONWire embedding pattern here because yaml.v3 panics on unexported concrete types behind interfaces in shadowed embedded fields, and fails to decode embedded fields when names collide (unlike encoding/json which handles both correctly). We round-trip through JSON instead.
func (*Node) RequireStringSlot ¶
RequireStringSlot returns the string value of a required slot. Returns an error if the slot is not set, or holds a non-string value. An empty string is valid — use GetSlot for optional slots where zero value is acceptable.
func (*Node) ResolvedSlots ¶
ResolvedSlots returns all slot values as a flat map. Promise slots are resolved from the results map; immediate slots are returned directly. Proxy slots are resolved from the optional proxyCtx map (used by gather for per-iteration item binding). Pass nil for results when all slots are immediate (e.g., in tests).
func (*Node) SetSlotImmediate ¶
SetSlotImmediate sets a slot to an immediate value.
func (*Node) SetSlotPromise ¶
SetSlotPromise sets a slot to a promise (reference to another node).
func (*Node) SetSlotProxy ¶
SetSlotProxy sets a slot to a gather proxy reference.
func (*Node) UnmarshalJSON ¶
UnmarshalJSON deserializes a node, creating a stubAction from the action name.
type NodeStatus ¶
type NodeStatus string
NodeStatus represents the execution status of a node.
const ( StatusPending NodeStatus = "pending" StatusCompleted NodeStatus = "completed" StatusSkipped NodeStatus = "skipped" StatusFailed NodeStatus = "failed" )
type Output ¶
type Output struct {
// contains filtered or unexported fields
}
Output represents a promise - a handle to a node's output that can flow through the graph to fill slots in other nodes.
When passed to a plan function's slot, it creates an edge in the graph. The same promise can flow to multiple slots (fan-out).
func ResolveInput ¶
ResolveInput extracts an *Output from a Starlark value. Returns an error if the value is not an Output.
func (*Output) DependOn ¶
DependOn creates an edge making the given node depend on this output's node.
func (*Output) FillSlot ¶
FillSlot fills a slot in the consumer node with this promise, creating an edge. This is called when a promise is passed to a plan function.
type Phase ¶
type Phase struct {
// ID is the unique identifier (e.g., "phase.install").
ID string `json:"id" yaml:"id"`
// Name is the phase name (e.g., "install").
Name string `json:"name" yaml:"name"`
// Status of this phase: pending, completed, failed, rolled_back, skipped.
Status PhaseStatus `json:"status" yaml:"status"`
// Retry governs retry behavior when inner nodes fail.
Retry *RetryPolicy `json:"retry,omitempty" yaml:"retry,omitempty"`
// NodeIDs lists the IDs of inner nodes belonging to this phase.
NodeIDs []string `json:"nodes,omitempty" yaml:"nodes,omitempty"`
// Compensate is the ID of the compensating action for rollback.
Compensate string `json:"compensate,omitempty" yaml:"compensate,omitempty"`
// Attempts records retry history (populated during execution).
Attempts []Attempt `json:"attempts,omitempty" yaml:"attempts,omitempty"`
// State holds execution metadata captured during the forward action.
// The compensating action reads this to know what to undo.
State map[string]any `json:"state,omitempty" yaml:"state,omitempty"`
}
Phase represents a lifecycle phase in the execution graph. Each phase owns a set of inner nodes and acts as an error boundary with retry and compensating action support (the Saga Pattern).
type PhaseStatus ¶
type PhaseStatus string
PhaseStatus represents the execution state of a phase.
const ( PhasePending PhaseStatus = "pending" PhaseCompleted PhaseStatus = "completed" PhaseFailed PhaseStatus = "failed" PhaseRolledBack PhaseStatus = "rolled_back" PhaseSkipped PhaseStatus = "skipped" )
type Receiver ¶
type Receiver struct {
// contains filtered or unexported fields
}
Receiver provides common implementations for Starlark binding namespaces. Embed this in concrete types to satisfy starlark.Value. Concrete types must implement starlark.HasAttrs (Attr and AttrNames) themselves.
func NewReceiver ¶
NewReceiver creates a new Receiver with the given namespace name.
type RetryPolicy ¶
type RetryPolicy struct {
// MaxAttempts is the maximum number of retries (0 = no retry, fail immediately).
MaxAttempts int `json:"max_attempts" yaml:"max_attempts"`
// Backoff is the delay strategy: none, linear, exponential.
Backoff BackoffStrategy `json:"backoff" yaml:"backoff"`
// InitialDelay is the delay before the first retry (Go duration string, e.g. "1s").
InitialDelay string `json:"initial_delay,omitempty" yaml:"initial_delay,omitempty"`
// MaxDelay caps the delay between retries (Go duration string, e.g. "30s").
MaxDelay string `json:"max_delay,omitempty" yaml:"max_delay,omitempty"`
}
RetryPolicy configures retry behavior for a phase.
func (*RetryPolicy) ComputeDelay ¶
func (r *RetryPolicy) ComputeDelay(attempt int) time.Duration
ComputeDelay returns the delay for a given attempt number (0-based).
func (*RetryPolicy) ParseInitialDelay ¶
func (r *RetryPolicy) ParseInitialDelay() time.Duration
ParseInitialDelay parses the InitialDelay string into a time.Duration. Returns 0 if the string is empty or unparseable.
func (*RetryPolicy) ParseMaxDelay ¶
func (r *RetryPolicy) ParseMaxDelay() time.Duration
ParseMaxDelay parses the MaxDelay string into a time.Duration. Returns 0 if the string is empty or unparseable.
type RollbackEntry ¶
type RollbackEntry struct {
// Phase is the phase name that was rolled back.
Phase string `json:"phase" yaml:"phase"`
// Compensate is the ID of the compensating action.
Compensate string `json:"compensate" yaml:"compensate"`
// Status is "completed" or "failed".
Status string `json:"status" yaml:"status"`
// Error is the error message if the compensating action failed.
Error string `json:"error,omitempty" yaml:"error,omitempty"`
}
RollbackEntry records a compensating action executed during rollback.
type Signature ¶
type Signature struct {
// Method is the signing method used (gpg, aws_kms, gcp_kms, azure_kv).
Method string `json:"method" yaml:"method"`
// Value is the signature data (base64-encoded).
Value string `json:"value" yaml:"value"`
// KeyID identifies the key used for signing.
// For GPG: fingerprint, for KMS: key ARN/ID/URL.
KeyID string `json:"key_id" yaml:"key_id"`
}
Signature contains the cryptographic signature of a graph.
type SlotValue ¶
type SlotValue struct {
// Immediate is the direct value (any type, known at analysis time).
Immediate any `json:"immediate,omitempty" yaml:"immediate,omitempty"`
// NodeRef is the ID of the node that produces this value (promise).
NodeRef string `json:"node_ref,omitempty" yaml:"node_ref,omitempty"`
// Slot is which output slot of the referenced node (empty = default output).
Slot string `json:"slot,omitempty" yaml:"slot,omitempty"`
// GatherRef is the gather node ID for proxy resolution.
GatherRef string `json:"gather_ref,omitempty" yaml:"gather_ref,omitempty"`
// Field is the field name to access on the proxy item.
Field string `json:"field,omitempty" yaml:"field,omitempty"`
}
SlotValue represents a value that fills a slot in a node. Three variants, mutually exclusive:
- Immediate: value known at analysis time
- Promise: reference to another node's output (NodeRef)
- Proxy: reference to a gather iteration item (GatherRef + Field)
func (SlotValue) IsImmediate ¶
IsImmediate returns true if this slot value is an immediate value.
type Summary ¶
type Summary struct {
TotalFiles int `json:"total_files,omitempty" yaml:"total_files,omitempty"`
Links int `json:"links,omitempty" yaml:"links,omitempty"`
Copies int `json:"copies,omitempty" yaml:"copies,omitempty"`
Templates int `json:"templates,omitempty" yaml:"templates,omitempty"`
Secrets int `json:"secrets,omitempty" yaml:"secrets,omitempty"`
Packages int `json:"packages,omitempty" yaml:"packages,omitempty"`
Skipped int `json:"skipped,omitempty" yaml:"skipped,omitempty"`
Failed int `json:"failed,omitempty" yaml:"failed,omitempty"`
BackedUp int `json:"backed_up,omitempty" yaml:"backed_up,omitempty"`
}
Summary contains execution statistics.