From 585395a40459cbc2a9a34e75818f5a7fbcfcd89d Mon Sep 17 00:00:00 2001
From: Rafal Kupka <324064+kupson@users.noreply.github.com>
Date: Tue, 2 Jul 2019 16:08:50 +0100
Subject: [PATCH] Add network backend using the lua-resty-http module.

---
 raven/senders/ngx-resty-http.lua | 236 +++++++++++++++++++++++++++++++
 1 file changed, 236 insertions(+)
 create mode 100644 raven/senders/ngx-resty-http.lua

diff --git a/raven/senders/ngx-resty-http.lua b/raven/senders/ngx-resty-http.lua
new file mode 100644
index 0000000..cab311b
--- /dev/null
+++ b/raven/senders/ngx-resty-http.lua
@@ -0,0 +1,236 @@
+-- vim: st=4 sts=4 sw=4 et:
+--- Network backend using the [lua-nginx-module](https://github.com/openresty/lua-nginx-module) cosocket API and [lua-resty-http](https://github.com/ledgetech/lua-resty-http) module.
+-- This module can be used with the raw Lua module for nginx or the OpenResty
+-- bundle.
+--
+-- As socket API is not available in all contexts, the messages are queued and
+-- processed in a timer when necessary. This can be forced for all messages too
+-- in order to not wait for the message to be sent (see the `async` filed).
+--
+-- It will require the `lua_ssl_trusted_certificate` to be set correctly when
+-- reporting to a HTTPS endpoint.
+--
+-- @module raven.senders.ngx-resty-http
+-- @copyright 2014-2017 CloudFlare, Inc.
+-- @license BSD 3-clause (see LICENSE file)
+
+-- luacheck: globals ngx
+
+local util = require 'raven.util'
+
+local ngx_socket = ngx.socket
+local ngx_get_phase = ngx.get_phase
+local string_format = string.format
+local table_remove = table.remove
+local parse_dsn = util.parse_dsn
+local generate_auth_header = util.generate_auth_header
+local _VERSION = util._VERSION
+local _M = {}
+
+-- provide a more sensible implementation of the error log function
+function util.errlog(...)
+    ngx.log(ngx.ERR, 'raven-lua failure: ', ...)
+end
+
+local CALLBACK_DEFAULT_ERRMSG =
+    "failed to configure http client (custom callback did not returned a value)"
+
+local function send_msg(self, msg)
+    local ok, err
+    local http = require "resty.http"
+    local httpc = http.new()
+
+    if self.configure_http_client then
+        ok, err = self.configure_http_client(self, httpc)
+        if not ok then
+            return nil, err or CALLBACK_DEFAULT_ERRMSG
+        end
+    end
+
+    ok, err = httpc:connect(self.target, self.port)
+    if not ok then
+        return nil, err
+    end
+
+    if self.protocol == 'https' then
+        -- TODO: session resumption?
+        ok, err = httpc:ssl_handshake(false, self.host, self.verify_ssl)
+        if not ok then
+            httpc:close()
+            return nil, err
+        end
+    end
+
+    local res
+    res, err = httpc:request(msg)
+    if not res then
+        httpc:close()
+        return nil, err
+    end
+
+    local status = res.status
+    local body
+    if res.has_body then
+        body, err = res:read_body()
+        if not body then
+            httpc:close()
+            return nil, err
+        end
+    end
+    httpc:close()
+
+    if status ~= 200 then
+        return nil, "Server response status not 200:" .. (status or "nil")
+    end
+
+    return body or ""
+end
+
+-- async task pushing: sometimes the socket API is not available, in this case,
+-- messages are pushed into a queue and sent in a timer. Only one timer at most
+-- is running per instance (and per worker): timers are a scarce resource, we
+-- don't want to exhaust the timer pool during message storms.
+
+local function send_task(premature, self)
+    if premature then
+        return
+    end
+
+    local ok, err = xpcall(function()
+        local send_queue = self.send_queue
+        while #send_queue > 0 do
+            local msg = send_queue[1]
+            -- do not remove the message yet as an empty queue is the signal to
+            -- re-start the task
+            local ok, err = send_msg(self, msg)
+            if not ok then
+                ngx.log(ngx.ERR, 'raven: failed to send message asyncronously: ',
+                    err, '. Drop the message.')
+            end
+            table_remove(send_queue, 1)
+        end
+    end, debug.traceback)
+
+    if not ok then
+        ngx.log(ngx.ERR, 'raven: failed to run the async sender task: ', err)
+        -- TODO: restart the task here? requires a extra counter as we don't want
+        -- to fail in loop indefinitely.
+    end
+    self.task_running = false
+end
+
+
+local mt = {}
+mt.__index = mt
+
+function mt:send(json_str)
+    local auth = generate_auth_header(self)
+    local msg = {
+        ["method"] = "POST",
+        ["path"] = self.request_uri,
+        ["headers"] = {
+            ["Host"] = self.host,
+            ["Connection"] = "close",
+            ["Content-Type"] = "application/json",
+            ["User-Agent"] = "raven-lua-ngx/" .. _VERSION,
+            ["X-Sentry-Auth"] = auth,
+        },
+        ["body"] = json_str,
+    }
+    local phase = ngx_get_phase()
+    -- rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*
+    if (not self.async) and (
+        phase == 'rewrite' or
+        phase == 'access' or
+        phase == 'content' or
+        phase == 'timer' or
+        phase == 'ssl_cert' or
+        phase == 'ssl_session_fetch'
+    ) then
+        -- socket is available
+        return send_msg(self, msg)
+    else
+        -- cannot use socket: push the message in the async queue
+        local send_queue = self.send_queue
+        local queue_size = #send_queue
+        if queue_size <= self.queue_limit then
+            send_queue[queue_size + 1] = msg
+            if not self.task_running then
+                local ok, err = ngx.timer.at(0, send_task, self)
+                if not ok then
+                    return nil, 'failed to schedule async sender task: ' .. err
+                end
+
+                -- assume the task is already running, as other messages might
+                -- be reported before it is actually scheduled and run.
+                self.task_running = true
+            end
+        else
+            return nil, 'failed to send message asyncronously: queue is full'
+        end
+        return true
+    end
+end
+
+--- Configuration table for the nginx sender.
+-- @field dsn DSN string
+-- @field verify_ssl Whether or not the SSL certificate is checked (boolean,
+--  defaults to false)
+-- @field configure_http_client Callback used to configure the created http
+--  client object (e.g. adjusting the timeout). Called with the sender
+--  object and http client object as arguments. Must return `true` or
+--  `nil, error_message`.
+-- @field queue_limit Maximum number of message in the asynchronous sending queue
+--  (default: 50)
+-- @field async Always send message asynchronously, even when it can be sent
+--  right away. This is to prevent to slow down processing while contacting the
+--  Sentry server. (default: false)
+-- @table sender_conf
+
+--- Create a new sender object for the given DSN
+-- @param conf Configuration table, see @{sender_conf}
+-- @return A sender object
+function _M.new(conf)
+    local obj, err = parse_dsn(conf.dsn)
+    if not obj then
+        return nil, err
+    end
+
+    obj.target = conf.target or obj.host
+    obj.verify_ssl = conf.verify_ssl
+    obj.configure_http_client = conf.configure_http_client
+    obj.queue_limit = conf.queue_limit or 50
+    obj.async = conf.async or false
+    obj.send_queue = {}
+    obj.task_running = false
+
+    return setmetatable(obj, mt)
+end
+
+--- Returns the value of the `server_name` variable if possible.
+-- Otherwise (wrong phase), this will return "undefined".
+--
+-- It is intended to be used as a `get_server_name` override on the main raven
+-- instance.
+--
+-- @usage
+-- local raven_ngx = require("raven.senders.ngx-resty-http")
+-- local rvn = raven.new(...)
+-- rvn.get_server_name = raven_ngx.get_server_name
+function _M.get_server_name()
+    local phase = ngx.get_phase()
+    -- the ngx.var.* API is not available in all contexts
+    if phase == "set" or
+        phase == "rewrite" or
+        phase == "access" or
+        phase == "content" or
+        phase == "header_filter" or
+        phase == "body_filter" or
+        phase == "log"
+    then
+        return ngx.var.server_name
+    end
+    return "undefined"
+end
+
+return _M