<<../../../_common/intro/_packages_intro.md>>
<<../../../_common/intro/_packages_serving.md>>
<<../../../_common/intro/_packages_storing.md>>
So far in this codelab, you‘ve been experiencing on demand software delivery to your device and you probably didn’t even know it! In this exercise, you'll peel back the covers and see the details of how packages are delivered and stored on a Fuchsia device.
<<../_common/_start_femu.md>>
List the package repositories configured in your package server:
ffx repository list
This command prints output similar to the following:
+----------------------+------+-----------------------------------------------+ | NAME | TYPE | EXTRA | +======================+======+===============================================+ | fuchsiasamples.com | pm | /home/alice/.package_repos/sdk-samples | +----------------------+------+-----------------------------------------------+ | workstation.qemu-x64 | pm | /home/alice/.local/share/Fuchsia/.../packages | +----------------------+------+-----------------------------------------------+
The workstation.qemu-x64 repository is created when you run the ffx product-bundle get command (previously in “Get started with the Fuchsia SDK” quickstart guide). This repository contains additional system packages for the workstation.qemu-x64 prebuilt image.
Start a local package server instance to begin serving these packages:
ffx repository server start
server is listening on [::]:8083
Configure the emulator to resolve package URLs for fuchsia.com from the local package server:
ffx target repository register -r workstation.qemu-x64 --alias fuchsia.com
With the local package server running, you can explore the list of packages that are available in the repository:
ffx repository package list -r workstation.qemu-x64
This command prints additional details about each package in the repository, including the individual components.
Packages are resolved and loaded on demand by a Fuchsia device. Take a look at this in action with the bouncing_ball example package.
From the device shell prompt, you can confirm whether a known package is currently on the device:
fssh pkgctl pkg-status fuchsia-pkg://fuchsia.com/bouncing_ball
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:
ffx log --filter pkg-resolver
This shows all the instances where a package was loaded from the package server.
From the device shell prompt, attempt to resolve the package:
fssh pkgctl resolve fuchsia-pkg://fuchsia.com/bouncing_ball
Notice the new lines added to the log output for pkg-resolver:
[128.297][core/pkg-resolver][pkg-resolver][I] Fetching blobs for fuchsia-pkg://workstation.qemu-x64/bouncing_ball: [ 9575f44e2e3eaa25d4e97864abc9e308ee83d2abfda836e3fd4454999b2166a9, ] [128.386][core/pkg-resolver][pkg-resolver][I] resolved fuchsia-pkg://fuchsia.com/bouncing_ball as fuchsia-pkg://workstation.qemu-x64/bouncing_ball to bb0515ee231c3b07da82234d015508f8799ed26b828e8dae16b3e9c59bd87cf2 with TUF
From the device shell prompt, check the package status again on the device:
fssh pkgctl pkg-status fuchsia-pkg://fuchsia.com/bouncing_ball
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!
Now that the bouncing_ball 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.
From the device shell prompt, use the pkgctl get-hash command to determine the package hash for bouncing_ball:
fssh pkgctl get-hash fuchsia-pkg://fuchsia.com/bouncing_ball
ef65e2ed...
Provide the full package hash to the pkgctl open command to view the package contents:
fssh pkgctl open ef65e2ed...
opening ef65e2ed... package contents: /bin/bouncing_ball /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/libsyslog.so /lib/libunwind.so.1 /meta/bouncing_ball.cmx /meta/contents /meta/package /meta/fuchsia.abi/abi-revision
This lists the package metadata and each of the content BLOBs in the package. You can see bin/ entries for executables, lib/ entries for shared library dependencies, additional metadata and resources.
Congratulations! You now have a better understanding of what makes Fuchsia unique and the goals driving this new platform's design.
In the next module, you‘ll learn more about building Fuchsia’s fundamental unit of software:
Fuchsia components