Packages

A package is the unit of installation on a Fuchsia system.

Anatomy

To be added...

Working with packages

The majority of these instructions rely on the pm tool which is available in //tools.

This document describes the various steps to build and install a package:

Build a package
Publish a package
Install a package
Run a component from an installed package

For more details about each step, see pm's help messages.

Build a package

To build a package:

Create the package ID file:
Note: $PACKAGE_DIR is a staging directory where the package is built.
```
pm -o $PACKAGE_DIR -n $PACKAGE_NAME init
```
This generates the package ID file implicitly as $PACKAGE_DIR/meta/package. Set $PACKAGE_ID_FILE accordingly for use in subsequent steps:
```
export PACKAGE_ID_FILE=${PACKAGE_DIR}/meta/package
```
$PACKAGE_ID_FILE will contain the following data:
```
{
  "name": "<package name>",
  "version": "<package version>"
}
```
Create the manifest file, $MANIFEST_FILE, that provides the path to the package ID file. Each line of a manifest file maps a single file that is contained in the package and is in the form of destination=source where:
- destination is the path to the file in the final package
- source is the path to the file on the host machine
The manifest file must include at least one line for the package ID file like this:
```
meta/package=<package ID file>
```
Generate the package metadata archive:
```
pm -o $PACKAGE_DIR -m $MANIFEST_FILE build
```
This creates the metadata archive at $PACKAGE_DIR/meta.far.
Create the package archive $PACKAGE_ARCHIVE:
```
pm -o $PACKAGE_DIR -m $MANIFEST_FILE archive
```
This command creates the package archive implicitly as $PACKAGE_DIR/$PACKAGE_NAME-0.far. Set $PACKAGE_ARCHIVE accordingly for use in subsequent steps:
```
export PACKAGE_ARCHIVE=${PACKAGE_DIR}/${PACKAGE_NAME}-0.far
```
If the contents of the package change, you need to re-run the pm -o $PACKAGE_DIR -m $MANIFEST_FILE archive command.

You have successfully built a package. You are now ready to publish the package.

Publish a package

To publish a package:

Initialize a directory, $REPO, that serves as a packages repository:
```
pm newrepo -repo $REPO
```
This creates a directory structure named $REPO that is ready for publishing packages.
Publish packages to the repository $REPO:
```
pm publish -a -r $REPO -f $PACKAGE_ARCHIVE
```
pm publish parses $PACKAGE_ARCHIVE and publishes the package in the provided $REPO directory. If you run this command multiple times with different package archives, pm publish publishes the packages to the same repository. New versions of a same package can be published using the same command.

You have successfully published a package. You are now ready to install a package.

Install a package

To install a package:

Start the package server:
```
pm serve -repo $REPO
```
By default, this starts an amber server on the host machine at port 8083.
(On the target device) Add the new repository as an update source with amberctl:
```
amberctl add_repo_cfg -n $REPO -f http://$HOST_ADDRESS:8083/config.json
```
If the component is not already on the system, amberctl installs the package. If the package already exists, amberctl installs any package updates.

You have successfully installed or updated the package. You are now ready to run a component from the installed package.

Run a component from an installed package

To run a component published in a package:

(On the target device) Run:

Note: $COMPONENT_URI is in this form fuchsia-pkg://${REPO}/${PACKAGE_NAME}#meta/<component name>.cmx.

run $COMPONENT_URI

You have successfully run a component from the installed package.