rewrite_by_lua_block {
    -- local b64 = require("ngx.base64")
    -- pull apipassword from SIA_API_AUTHORIZATION environment variable
    -- local apipassword = os.getenv("SIA_API_AUTHORIZATION")
    -- encode the user:password authorization string
    -- (in our case user is empty so it is just :password)
    -- local content = b64.encode_base64url(":" .. apipassword)
    -- set authorization header with proper base64 encoded string
    ngx.req.set_header("Authorization", "Basic " .. os.getenv("SIA_API_AUTHORIZATION"))
}