技术细节

本节描述知晓云系统中的技术细节以及限制。

标准版本中的限制条件

知晓云的各标准版本均可承载高并发量之负载,作为服务承诺的一部分,不同套餐可保证承载量不低于以下之描述:

  • 免费版: 10 QPS / 应用
  • 教育版: 20 QPS / 应用
  • 个人版: 100 QPS / 应用
  • 商用版: 300 QPS / 应用

以上限制条件可满足绝大部分用户的正常工作负载,若有更高的 QPS 需求,请通过工单联系知晓云客服。

云函数

GPL Code

云函数的构建离不开开源社区的贡献。在云函数的实现中,知晓云使用了诸多 GPL 协议的源代码并进行了修改。

知晓云团队基于以下工具构建了云函数功能:

  • buildroot
  • busybox
  • Node.js

所有的 GPL 源代码可通过发起工单的方式获取。

云函数的实现

云函数是基于知晓云团队自研的轻量级容器 Iceberg 的,并非基于 docker 或类似方案实现的。每次用户云函数执行完后,容器即立即销毁。

云函数的临时文件存储

临时文件可存储在 /tmp 中。用户有高达 64MB 的高速临时文件存储空间可供使用。临时文件的生命周期限制在云函数的执行周期中,云函数返回后临时文件即时销毁,并将无法找回。

云函数的网络请求

云函数内无法对外界发起直接的网络请求。若希望发起请求,应使用 SDK 中提供的方法进行。

执行环境内的可用工具、资源

为方便使用,知晓云在云函数的执行环境内准备了如下工具/资源:

  • gd
  • ghostscript
  • imagemagick

这里我们可以通过 child_process 模块来调用这些二进制文件

示例代码

  1. // 使用 convert 命令转换图片
  2. const { spawn } = require('child_process');
  3. const cmd = spawn('convert', ['/tmp/1.png', '-resize', '50%', '/tmp/1.jpg']);
  4. cmd.stdout.on('data', (data) => {
  5. console.log(`stdout: ${data}`);
  6. });
  7. cmd.stderr.on('data', (data) => {
  8. console.log(`stderr: ${data}`);
  9. });
  10. cmd.on('close', (code) => {
  11. console.log(`child process exited with code ${code}`);
  12. });

以下 emoji 字体:

  • /usr/share/fonts/google-material/MaterialIcons-Regular.ttf

以下西文字体:

  • /usr/share/fonts/ttf-bitstream-vera/VeraBd.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraBI.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraIt.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraMoBd.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraMoBI.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraMoIt.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraMono.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraSeBd.ttf
  • /usr/share/fonts/ttf-bitstream-vera/VeraSe.ttf
  • /usr/share/fonts/ttf-bitstream-vera/Vera.ttf
  • /usr/share/fonts/cantarell/Cantarell-Regular.otf
  • /usr/share/fonts/cantarell/Cantarell-Oblique.otf
  • /usr/share/fonts/cantarell/Cantarell-Bold.otf
  • /usr/share/fonts/cantarell/Cantarell-BoldOblique.otf
  • /usr/share/fonts/dejavu/DejaVuSansMono-BoldOblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSansMono-Bold.ttf
  • /usr/share/fonts/dejavu/DejaVuSansMono-Oblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSansMono.ttf
  • /usr/share/fonts/dejavu/DejaVuSans.ttf
  • /usr/share/fonts/dejavu/DejaVuSans-BoldOblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSans-Bold.ttf
  • /usr/share/fonts/dejavu/DejaVuSans-ExtraLight.ttf
  • /usr/share/fonts/dejavu/DejaVuSans-Oblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSerif.ttf
  • /usr/share/fonts/dejavu/DejaVuSerif-BoldItalic.ttf
  • /usr/share/fonts/dejavu/DejaVuSerif-Bold.ttf
  • /usr/share/fonts/dejavu/DejaVuSerif-Italic.ttf
  • /usr/share/fonts/dejavu/DejaVuSansCondensed-BoldOblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSansCondensed-Bold.ttf
  • /usr/share/fonts/dejavu/DejaVuSansCondensed-Oblique.ttf
  • /usr/share/fonts/dejavu/DejaVuSansCondensed.ttf
  • /usr/share/fonts/dejavu/DejaVuSerifCondensed-BoldItalic.ttf
  • /usr/share/fonts/dejavu/DejaVuSerifCondensed-Bold.ttf
  • /usr/share/fonts/dejavu/DejaVuSerifCondensed-Italic.ttf
  • /usr/share/fonts/dejavu/DejaVuSerifCondensed.ttf
  • /usr/share/fonts/liberation/LiberationMono-BoldItalic.ttf
  • /usr/share/fonts/liberation/LiberationMono-Bold.ttf
  • /usr/share/fonts/liberation/LiberationMono-Italic.ttf
  • /usr/share/fonts/liberation/LiberationMono-Regular.ttf
  • /usr/share/fonts/liberation/LiberationSans-BoldItalic.ttf
  • /usr/share/fonts/liberation/LiberationSans-Bold.ttf
  • /usr/share/fonts/liberation/LiberationSans-Italic.ttf
  • /usr/share/fonts/liberation/LiberationSans-Regular.ttf
  • /usr/share/fonts/liberation/LiberationSerif-BoldItalic.ttf
  • /usr/share/fonts/liberation/LiberationSerif-Bold.ttf
  • /usr/share/fonts/liberation/LiberationSerif-Italic.ttf
  • /usr/share/fonts/liberation/LiberationSerif-Regular.ttf

以下中文字体:

  • /usr/share/fonts/arphic-bkai00mp/bkai00mp.ttf
  • /usr/share/fonts/arphic-bsmi00lp/bsmi00lp.ttf
  • /usr/share/fonts/arphic-gbsn00lp/gbsn00lp.ttf
  • /usr/share/fonts/arphic-gkai00mp/gkai00mp.ttf
  • /usr/share/fonts/source-han-sans/SourceHanSans-Bold.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-ExtraLight.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-Heavy.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-Light.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-Medium.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-Normal.ttc
  • /usr/share/fonts/source-han-sans/SourceHanSans-Regular.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-Bold.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-ExtraLight.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-Heavy.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-Light.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-Medium.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-Regular.ttc
  • /usr/share/fonts/source-han-serif/SourceHanSerif-SemiBold.ttc