软件交付
<<../../_common/intro/_packages_intro.md>>
<<../../_common/intro/_packages_serving.md>>
<<../../_common/intro/_packages_storing.md>>
练习：包
在之前的本系列代码练习中，虽然您可能没有意识到，但您已经体验过到设备的软件按需交付。在本练习中，您将进一步揭开它的神秘面纱，了解到包被交付和存储到 Fuchsia 设备中的过程的具体细节。
<<../_common/_restart_femu.md>>
启动本地包服务器
运行如下命令，以启动包服务器并允许模拟器加载软件包：
该命令打印的输出类似如下所示。它表示服务器正在运行，并已成功将模拟器注册为目标设备：
```none {:.devsite-disable-click-to-copy} [serve-updates] Discovery... [serve-updates] Device up [serve-updates] Registering devhost as update source [serve-updates] Ready to push packages! [serve-updates] Target uptime: 139 [pm auto] adding client: [fe80::5888:cea3:7557:7384%qemu]:46126 [pm auto] client count: 1
<!--
### Examine the package server
-->
### 检查包服务器
<!--
The `fx serve-updates` command runs a **local package server** used to deliver
packages to the target devices. By default, this server runs at on port 8083.
-->
`fx serve-updates` 命令会启动用于将包交付到目标设备的 **本地包服务器**。该服务器默认在 8083 端口上运行。
<!--
Open a browser to `http://localhost:8083`. This loads an HTML page listing all
the packages currently available in the package repository. Each one of these
are packages that can be delivered to the device.
-->
在浏览器中访问 `http://localhost:8083`，会加载出一个当前包仓库中可用的包的列表的网页。列表中的每一项都是可被交付到设备的包。
<!--
### Monitor package loading
-->
### 监视包加载
<!--
Packages are resolved and loaded on demand by a Fuchsia device. Take a look at
this in action with the `spinning-square` example package.
-->
包由 Fuchsia 设备按需解析并加载。让我们在 `spinning-square` 示例包上进行操作来稍作展示。
<!--
From the device shell prompt, you can confirm whether a known package is
currently on the device:
-->
在设备命令行中，您可以确定某个已知的包目前是否在设备上。
```posix-terminal
fx shell pkgctl pkg-status fuchsia-pkg://fuchsia.com/spinning-square-rs
```none {:.devsite-disable-click-to-copy} Package in registered TUF repo: yes (merkle=ef65e2ed...) Package on disk: no
<!--
Open a new terminal and begin streaming the device logs for `pkg-resolver`:
-->
打开新终端，开始流式传输 `pkg-resolver` 的设备日志。
```posix-terminal
ffx log --filter pkg-resolver
这里展示了从包服务器加载的包的所有实例。
在设备命令行中，尝试解析包：
注意 pkg-resolver 的输出中增加的新行：
```none {:.devsite-disable-click-to-copy} [pkg-resolver][pkg-resolver][I] Fetching blobs for fuchsia-pkg://devhost/spinning-square-rs: [ 6b547fb59fda56866eea01cda90add0aabc1af7c7418c7850011ec6e99a996f1, 7c1a9fd1c11e9b6b1d3c3184cf350cecfc91ec083b412d20c18b5187d0983d88, ] [pkg-resolver][pkg-resolver][I] resolved fuchsia-pkg://fuchsia.com/spinning-square-rs as fuchsia-pkg://devhost/spinning-square-rs to 21967ecc643257800b8ca14420c7f023c1ede7a76068da5faedf328f9d9d3649 with TUF
<!--
From the device shell prompt, check the package status again on the device:
-->
在设备命令行中，再次在设备上查看包状态：
```posix-terminal
fx shell pkgctl pkg-status fuchsia-pkg://fuchsia.com/spinning-square-rs
```none {:.devsite-disable-click-to-copy} Package in registered TUF repo: yes (merkle=ef65e2ed...) Package on disk: yes (path=/pkgfs/versions/ef65e2ed...)
<!--
Fuchsia resolved the package and loaded it from the local TUF repository on
demand!
-->
Fuchsia 解析了包并按需从本地 TUF 仓库中将其加载了！
<!--
### Explore package metadata
-->
### 探索包的元数据
<!--
Now that the `spinning-square` package has successfully been resolved, you can
explore the package contents. Once resolved, the package is referenced on the
target device using its content address.
-->
现在 `spinning-square` 包已经成功解析，接下来可以探索包内容。在解析之后，包就可以在目标设备上用它的内容地址引用。
<!--
From the device shell prompt, use the `pkgctl get-hash` command to determine the
package hash for `spinning-square`:
-->
在设备命令行中，可以使用 `pkgctl get-hash` 命令来确认 `spinning-square` 的包摘要。
```posix-terminal
fx shell pkgctl get-hash fuchsia-pkg://fuchsia.com/spinning-square-rs
该命令会返回如下的唯一包摘要：
```none {:.devsite-disable-click-to-copy} ef65e2ed...
<!--
Provide the full package hash to the `pkgctl open` command to view the package
contents:
-->
使用 `pkgctl open` 命令并提供完整的包摘要，来查看包内容。
```posix-terminal
fx shell pkgctl open {{ '<var>' }}ef65e2ed...{{ '</var>' }}
none {:.devsite-disable-click-to-copy}
opening ef65e2ed...
package contents:
/bin/spinning_square
/lib/VkLayer_khronos_validation.so
/lib/ld.so.1
/lib/libasync-default.so
/lib/libbackend_fuchsia_globals.so
/lib/libc++.so.2
/lib/libc++abi.so.1
/lib/libfdio.so
/lib/librust-trace-provider.so
/lib/libstd-e3c06c8874beb723.so
/lib/libsyslog.so
/lib/libtrace-engine.so
/lib/libunwind.so.1
/lib/libvulkan.so
/meta/contents
/meta/package
/meta/spinning-square-rs.cm
/meta/spinning-square-rs.cmx
/data/fonts/RobotoSlab-Regular.ttf
/meta/fuchsia.abi/abi-revision
/data/vulkan/explicit_layer.d/VkLayer_khronos_validation.json
这个命令列出了包的元数据和包中的每个内容 BLOB（Binary Large OBject，二进制大型对象）。其中的 bin/ 项目对应可执行文件，lib/
项目对应共享库依赖，还有后面的额外元数据和资源。
接下来是？
祝贺！您现在对 Fuchsia 的独特性和这样一个新平台的设计目标都有了更好的理解。
在下一个模块中，您将了解到有关 Fuchsia 这个开源项目和用于构建与自定义系统的工具的更多知识：