function _M.access()

in apisix/plugins/traffic-split.lua [229:302]

• 62 lines of code
• 16 McCabe index (conditional complexity)

function _M.access(conf, ctx)
    if not conf or not conf.rules then
        return
    end

    local weighted_upstreams
    local match_passed = true

    for _, rule in ipairs(conf.rules) do
        
        if rule.weighted_upstreams then
            for _, wupstream in ipairs(rule.weighted_upstreams) do
                local ups_id = wupstream.upstream_id
                if ups_id then
                    local ups = upstream.get_by_id(ups_id)
                    if not ups then
                        return 500, "failed to fetch upstream info by "
                                    .. "upstream id: " .. ups_id
                    end
                end
            end
        end

        if not rule.match then
            match_passed = true
            weighted_upstreams = rule.weighted_upstreams
            break
        end

        for _, single_match in ipairs(rule.match) do
            local expr, err = expr.new(single_match.vars)
            if err then
                core.log.error("vars expression does not match: ", err)
                return 500, err
            end

            match_passed = expr:eval(ctx.var)
            if match_passed then
                break
            end
        end

        if match_passed then
            weighted_upstreams = rule.weighted_upstreams
            break
        end
    end

    core.log.info("match_passed: ", match_passed)

    if not match_passed then
        return
    end

    local rr_up, err = lrucache(weighted_upstreams, nil, new_rr_obj, weighted_upstreams)
    if not rr_up then
        core.log.error("lrucache roundrobin failed: ", err)
        return 500
    end

    local upstream = rr_up:find()
    if upstream and type(upstream) == "table" then
        core.log.info("upstream: ", core.json.encode(upstream))
        return set_upstream(upstream, ctx)
    elseif upstream and upstream ~= "plugin#upstream#is#empty" then
        ctx.upstream_id = upstream
        core.log.info("upstream_id: ", upstream)
        return
    end

    ctx.upstream_id = nil
    core.log.info("route_up: ", upstream)
    return
end