カスタムエンティティのキャッシュ

-- handler.lua

local CustomHandler = {
  VERSION  = "1.0.0",
  PRIORITY = 10,
}

local kong = kong

local function load_credential(key)
  local credential, err = kong.db.keyauth_credentials:select_by_key(key)
  if not credential then
    return nil, err
  end
  return credential
end


function CustomHandler:access(config)

  -- retrieve the apikey from the request querystring
  local key = kong.request.get_query_arg("apikey")

  local credential_cache_key = kong.db.keyauth_credentials:cache_key(key)

  -- We are using cache.get to first check if the apikey has been already
  -- stored into the in-memory cache. If it's not, then we lookup the datastore
  -- and return the credential object. Internally cache.get will save the value
  -- in-memory, and then return the credential.
  local credential, err = kong.cache:get(credential_cache_key, nil,
                                         load_credential, credential_cache_key)
  if err then
    kong.log.err(err)
    return kong.response.exit(500, {
      message = "Unexpected error"
    })
  end

  if not credential then
    -- no credentials in cache nor datastore
    return kong.response.exit(401, {
      message = "Invalid authentication credentials"
    })
  end

  -- set an upstream header if the credential exists and is valid
  kong.service.request.set_header("X-API-Key", credential.apikey)
end


return CustomHandler

local typedefs = require "kong.db.schema.typedefs"


return {
  -- this plugin only results in one custom DAO, named `keyauth_credentials`:
  keyauth_credentials = {
    name                  = "keyauth_credentials", -- the actual table in the database
    endpoint_key          = "key",
    primary_key           = { "id" },
    cache_key             = { "key" },
    generate_admin_api    = true,
    admin_api_name        = "key-auths",
    admin_api_nested_name = "key-auth",    
    fields = {
      {
        -- a value to be inserted by the DAO itself
        -- (think of serial id and the uniqueness of such required here)
        id = typedefs.uuid,
      },
      {
        -- also interted by the DAO itself
        created_at = typedefs.auto_timestamp_s,
      },
      {
        -- a foreign key to a consumer's id
        consumer = {
          type      = "foreign",
          reference = "consumers",
          default   = ngx.null,
          on_delete = "cascade",
        },
      },
      {
        -- a unique API key
        key = {
          type      = "string",
          required  = false,
          unique    = true,
          auto      = true,
        },
      },
    },
  },
}

cache_key = kong.db.<dao id="sl-md0000000">:cache_key(arg1, arg2, arg3, ...)

local cache_key = kong.db.keyauth_credentials:cache_key("abcd")

local key       = kong.request.get_query_arg("apikey")
local cache_key = kong.db.keyauth_credentials:cache_key(key)

local credential, err = kong.cache:get(cache_key, nil, load_entity_key, apikey)
if err then
  kong.log.err(err)
  return kong.response.exit(500, { message = "Unexpected error" })
end

if not credential then
  return kong.response.exit(401, { message = "Invalid authentication credentials" })
end


-- do something with the credential

function MyCustomHandler:init_worker()
  -- listen to all CRUD operations made on Consumers
  kong.worker_events.register(function(data)

  end, "crud", "consumers")

  -- or, listen to a specific CRUD operation only
  kong.worker_events.register(function(data)
    kong.log.inspect(data.operation)  -- "update"
    kong.log.inspect(data.old_entity) -- old entity table (only for "update")
    kong.log.inspect(data.entity)     -- new entity table
    kong.log.inspect(data.schema)     -- entity's schema
  end, "crud", "consumers:update")
end

kong.worker_events.register(function(data)
  if data.operation == "delete" then
    local cache_key = data.entity.id
    kong.cache:invalidate("prefix:" .. cache_key)
  end
end, "crud", "consumers")