Entry Registry

Query and modify registered entries. Access metadata, snapshots, and version history.

Loading

local registry = require("registry")

Entry Structure

{
    id = "app.lib:assert",     -- string: "namespace:name"
    kind = "function.lua",     -- string: entry type
    meta = {type = "test"},    -- table: searchable metadata
    data = {...}               -- any: entry payload
}

Get Entry

local entry, err = registry.get("app.lib:assert")

Permission: registry.get on entry ID

Find Entries

local entries, err = registry.find({[".kind"] = "function.lua"})
local entries, err = registry.find({[".kind"] = "http.endpoint", [".ns"] = "app.api"})

Filter fields match against entry metadata.

Parse ID

local id = registry.parse_id("app.lib:assert")
-- id.ns = "app.lib", id.name = "assert"

Snapshots

Point-in-time view of the registry:

local snap, err = registry.snapshot()           -- current state
local snap, err = registry.snapshot_at(5)       -- at version 5

Snapshot Methods

Method	Returns	Description
`snap:entries()`	`Entry[], error`	All accessible entries
`snap:get(id)`	`Entry, error`	Single entry by ID
`snap:find(filter)`	`Entry[]`	Filter entries
`snap:namespace(ns)`	`Entry[]`	Entries in namespace
`snap:version()`	`Version`	Snapshot version
`snap:changes()`	`Changes`	Create changeset

Versions

local version, err = registry.current_version()
local versions, err = registry.versions()

print(version:id())       -- numeric ID
print(version:string())   -- display string
local prev = version:previous()  -- previous version or nil
local next = version:next()      -- next version or nil

History

local hist, err = registry.history()
local versions, err = hist:versions()
local version, err = hist:get_version(5)
local snap, err = hist:snapshot_at(version)

Changesets

Build and apply modifications:

local snap, err = registry.snapshot()
local changes = snap:changes()

changes:create({
    id = "test:new_entry",
    kind = "test.kind",
    meta = {type = "test"},
    data = {config = "value"}
})

changes:update({
    id = "test:existing",
    kind = "test.kind",
    meta = {updated = true},
    data = {new_value = true}
})

changes:delete("test:old_entry")

local new_version, err = changes:apply()

Permission: registry.apply for changes:apply()

Changes Methods

Method	Description
`changes:create(entry)`	Add create operation
`changes:update(entry)`	Add update operation
`changes:delete(id)`	Add delete operation (string or `{ns, name}`)
`changes:ops()`	Get pending operations
`changes:apply()`	Apply changes, returns new Version

Apply Version

Roll back or forward to a specific version:

local prev = current_version:previous()
local ok, err = registry.apply_version(prev)

Permission: registry.apply_version

Build Delta

Compute operations to transition between states:

local from = {{id = "test:a", kind = "test", meta = {}, data = {}}}
local to = {{id = "test:b", kind = "test", meta = {}, data = {}}}

local ops, err = registry.build_delta(from, to)
for _, op in ipairs(ops) do
    print(op.kind, op.entry.id)  -- "entry.create", "entry.update", "entry.delete"
end

Permissions

Permission	Resource	Description
`registry.get`	entry ID	Read entry (also filters find/entries results)
`registry.apply`	-	Apply changeset
`registry.apply_version`	-	Apply/rollback version

Errors

Condition	Kind
Entry not found	`errors.NOT_FOUND`
Version not found	`errors.NOT_FOUND`
Permission denied	`errors.PERMISSION_DENIED`
Invalid parameter	`errors.INVALID`
No changes to apply	`errors.INVALID`
Registry not available	`errors.INTERNAL`

See Error Handling for working with errors.