rollouts/lua_configuration/networking.istio.io/VirtualService/trafficRouting.lua

126 lines
4.2 KiB
Lua

spec = obj.data.spec
if obj.canaryWeight == -1 then
obj.canaryWeight = 100
obj.stableWeight = 0
end
function GetHost(destination)
local host = destination.destination.host
dot_position = string.find(host, ".", 1, true)
if (dot_position) then
host = string.sub(host, 1, dot_position - 1)
end
return host
end
-- find routes of VirtualService with stableService
function GetRulesToPatch(spec, stableService, protocol)
local matchedRoutes = {}
if (spec[protocol] ~= nil) then
for _, rule in ipairs(spec[protocol]) do
-- skip routes contain matches
if (rule.match == nil) then
for _, route in ipairs(rule.route) do
if GetHost(route) == stableService then
table.insert(matchedRoutes, rule)
end
end
end
end
end
return matchedRoutes
end
function CalculateWeight(route, stableWeight, n)
local weight
if (route.weight) then
weight = math.floor(route.weight * stableWeight / 100)
else
weight = math.floor(stableWeight / n)
end
return weight
end
-- generate routes with matches, insert a rule before other rules, only support http headers, cookies etc.
function GenerateRoutesWithMatches(spec, matches, stableService, canaryService)
for _, match in ipairs(matches) do
local route = {}
route["match"] = {}
for key, value in pairs(match) do
local vsMatch = {}
vsMatch[key] = {}
for _, rule in ipairs(value) do
if rule["type"] == "RegularExpression" then
matchType = "regex"
elseif rule["type"] == "Exact" then
matchType = "exact"
elseif rule["type"] == "Prefix" then
matchType = "prefix"
end
if key == "headers" then
vsMatch[key][rule["name"]] = {}
vsMatch[key][rule["name"]][matchType] = rule.value
else
vsMatch[key][matchType] = rule.value
end
end
table.insert(route["match"], vsMatch)
end
route.route = {
{
destination = {}
}
}
-- stableService == canaryService indicates DestinationRule exists and subset is set to be canary by default
if stableService == canaryService then
route.route[1].destination.host = stableService
route.route[1].destination.subset = "canary"
else
route.route[1].destination.host = canaryService
end
table.insert(spec.http, 1, route)
end
end
-- generate routes without matches, change every rule whose host is stableService
function GenerateRoutes(spec, stableService, canaryService, stableWeight, canaryWeight, protocol)
local matchedRules = GetRulesToPatch(spec, stableService, protocol)
for _, rule in ipairs(matchedRules) do
local canary
if stableService ~= canaryService then
canary = {
destination = {
host = canaryService,
},
weight = canaryWeight,
}
else
canary = {
destination = {
host = stableService,
subset = "canary",
},
weight = canaryWeight,
}
end
-- incase there are multiple versions traffic already, do a for-loop
for _, route in ipairs(rule.route) do
-- update stable service weight
route.weight = CalculateWeight(route, stableWeight, #rule.route)
end
table.insert(rule.route, canary)
end
end
if (obj.matches)
then
GenerateRoutesWithMatches(spec, obj.matches, obj.stableService, obj.canaryService)
else
GenerateRoutes(spec, obj.stableService, obj.canaryService, obj.stableWeight, obj.canaryWeight, "http")
GenerateRoutes(spec, obj.stableService, obj.canaryService, obj.stableWeight, obj.canaryWeight, "tcp")
GenerateRoutes(spec, obj.stableService, obj.canaryService, obj.stableWeight, obj.canaryWeight, "tls")
end
return obj.data