wehub-resource-sync
87 lines
2.5 KiB
Lua
87 lines
2.5 KiB
Lua
local constants = require "kong.constants"
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local utils = require "kong.db.utils"
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local utils_toposort = utils.topological_sort
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local sort = table.sort
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local CORE_ENTITIES = constants.CORE_ENTITIES
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local sort_core_first do
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local CORE_SCORE = {}
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for i = 1, #CORE_ENTITIES do
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CORE_SCORE[CORE_ENTITIES[i]] = 1
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end
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CORE_SCORE["workspaces"] = 2
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sort_core_first = function(a, b)
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local sa = CORE_SCORE[a.name] or 0
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local sb = CORE_SCORE[b.name] or 0
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if sa == sb then
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-- reverse alphabetical order, so that items end up ordered alphabetically
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-- (utils_toposort does "neighbors" before doing "current")
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return a.name > b.name
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end
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return sa < sb
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end
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end
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-- Given an array of schemas, return a copy of it sorted so that:
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--
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-- * If schema B has a foreign key to A, then B appears after A
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-- * When there's no foreign keys, core schemas appear before plugin entities
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-- * If none of the rules above apply, schemas are sorted alphabetically by name
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--
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-- The function returns an error if cycles are found in the schemas
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-- (i.e. A has a foreign key to B and B to A)
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--
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-- @tparam array schemas an array with zero or more schemas
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-- @treturn array|nil an array of schemas sorted topologically, or nil if cycle was found
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-- @treturn nil|string nil if the schemas were sorted, or a message if a cycle was found
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-- @usage
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-- local res = topological_sort({ services, routes, plugins, consumers })
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-- assert.same({ consumers, services, routes, plugins }, res)
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local schema_topological_sort = function(schemas)
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local s
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local schemas_by_name = {}
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local copy = {}
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for i = 1, #schemas do
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s = schemas[i]
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schemas_by_name[s.name] = s
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copy[i] = schemas[i]
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end
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schemas = copy
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sort(schemas, sort_core_first)
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-- given a schema, return all the schemas to which it has references
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-- (and are in the list of the `schemas` provided)
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local get_schema_neighbors = function(schema)
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local neighbors = {}
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local neighbors_len = 0
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local neighbor
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for _, field in schema:each_field() do
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if field.type == "foreign" then
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neighbor = schemas_by_name[field.reference] -- services
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if neighbor then
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neighbors_len = neighbors_len + 1
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neighbors[neighbors_len] = neighbor
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end
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-- else the neighbor points to an unknown/uninteresting schema. This happens in tests.
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end
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end
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return neighbors
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end
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return utils_toposort(schemas, get_schema_neighbors)
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end
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return schema_topological_sort
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