docs/development/tools/ffx/getting-started.md - fuchsia - Git at Google

 # Getting started with ffx

 This doc will guide you through some of the features of `ffx`. For an overview
 of the design and components of `ffx`, see [the ffx overview](/docs/development/tools/ffx/overview.md).

 ## Contacting the ffx team

 If you discover possible bugs or have questions or suggestions,
 [file a bug](https://issues.fuchsia.dev/issues/new?component=1378294&template=1838957).

 ## Prerequisites

 To follow the examples in this doc, you'll need a Fuchsia device running. If you
 don't have a physical device connected, you can use an emulator.

 To start an emulator with networking enabled but without graphical user
 interface support, run `ffx emu start --headless`.

 For more information on configuring the emulator
 see, [Start the Fuchsia emulator](/docs/get-started/set_up_femu.md).

 Your device must be running a `core`
 [product configuration](/docs/development/build/build_system/boards_and_products.md)
 or a product configuration that extends `core` (such as `workstation_eng`).

 Optionally, you can run `ffx log`, which will provide some additional information
 about the interactions between `ffx` and your Fuchsia target device.

 ## Introduction

 After following all the prerequisites, run the following in a terminal:

 ```posix-terminal
 fx ffx help
 ```

 This will list all of the available `ffx` subcommands. You'll see something
 like:

 ```none
 Usage: ffx [-c <config>] [-e <env>] [-t <target>] [<command>] [<args>]

 Fuchsia's developer tool

 Options:
   -c, --config      override default configuration
   -e, --env         override default environment settings
   -t, --target      apply operations across single or multiple targets
   --help            display usage information

 Commands:
   component         Discover and manage components
   config            View and switch default and user configurations
   daemon            Interact with/control the ffx daemon
   diagnostic        Run diagnostic tests on Fuchsia targets
   docs              View suite of docs for ffx and for Fuchsia
   doctor            Run common checks for the ffx tool and host environment
   emulator          Start and manage Fuchsia emulators
   overnet           Interact with the Overnet mesh
   package           Create and publish Fuchsia packages
   sdk               Modify or query the installed SDKs
   target            Interact with a target device or emulator
   vendor            Run partner plugins
   version           Print out ffx tool and daemon versions
 ```

 You can use `fx ffx help <subcommand>` or `fx ffx <subcommand> --help` to see
 more about any subcommand.

 ## Interacting with target devices

 In a terminal, run the following:

 ```posix-terminal
 fx ffx target list
 ```

 You'll see a list of devices that `ffx` has discovered. For example, with a
 single emulator running, output looks like:

 ```none
 NAME                    SERIAL       TYPE       STATE      ADDRS/IP                       RCS
 fuchsia-emulator  <unknown>    Unknown    Product    [fe80::5054:ff:fe63:5e7a%4]    N
 ```

 `RCS`: Indicates whether there is a reachable instance of the Remote Control
 Service (RCS) running on the device.

 In order to get `ffx` to automatically connect to a device, you must either have
 set the target's nodename to be the default target, or attempt to interact with the
 device.

 To set the target to be the default, run:

 ```posix-terminal
 fx ffx target default set $NODENAME
 ```

 If the default target has been set prior to starting the daemon, waiting a few seconds
 should yield a change to the `RCS` status to show `Y`.

 If the default target has been set after starting the daemon, attempting to interact
 with the target should be sufficient to kick off a connection, like the following

 ```posix-terminal
 fx ffx component list
 ```

 Note: If the default target has been set, and you are unable to run that command
 against the target, [reach out](#contacting_the_ffx_team) to the `ffx` team.

 Then the next time you list targets you should see that an `RCS` connection
 is active.

 ```none
 $ fx ffx target list
 NAME                    SERIAL       TYPE       STATE      ADDRS/IP                       RCS
 fuchsia-emulator  <unknown>    Unknown    Product    [fe80::5054:ff:fe63:5e7a%4]    Y
 ```

 If a target has been set as default there will be a `*` next to it.

 If you had `ffx log` running, you should also see something like the following in
 the logs:

 ```none
 [00009.776170][28540][28542][remote-control, remote_control_bin] INFO: published remote control service to overnet
 ```

 NOTE: if the `RCS` column remains `N` for an extended amount of time and you have
 already set this target's nodename to `target.default` _before_ initially starting
 ffx, [reach out](#contacting_the_ffx_team) to the `ffx` team.

 ### On Default Targets

 Above we covered setting the default target using the command

 ```posix-terminal
 fx ffx target default set
 ```

 It is also possible to set the default target on a per-command basis using the
 `--target` flag like so.

 ```posix-terminal
 fx ffx --target $NODENAME component list
 ```

 ### Interacting with multiple devices

 TODO: fill this out.

 ### Controlling the state of target devices

 You can use the `target off` and `target reboot` subcommands to power-off or
 reboot a device, respectively.

 ## Configuration

 See documentation for the [config command](/docs/development/tools/ffx/commands/config.md).

 ## Interacting with Components

 ### Monikers

 Many `ffx` commands that use components take monikers as a parameter. You can read more about
 monikers and their syntax in [component moniker documentation](/docs/reference/components/moniker.md).

 ### Finding components

 The `component list` command will output monikers of all components that currently exist
 in the component topology.

 ```none
 $ fx ffx component list
 /
 /bootstrap
 /bootstrap/archivist
 /bootstrap/base_resolver
 /bootstrap/console
 /bootstrap/console-launcher
 /bootstrap/cr50_agent
 /bootstrap/device_name_provider
 /bootstrap/driver_index
 /bootstrap/driver_manager
 /bootstrap/flashmap
 /bootstrap/fshost
 /bootstrap/fshost/blobfs
 /bootstrap/fshost/blobfs/decompressor
 ...
 ```

 You can use the `component select capability` command to search for components that use/expose
 a capability with a given name.

 The following command will display all components that use/expose the `diagnostics` capability:

 ```none
 $ fx ffx component capability diagnostics
 Exposed:
   /bootstrap/archivist
   /bootstrap/base_resolver
   /bootstrap/driver_manager
   /bootstrap/fshost
   /bootstrap/fshost/blobfs
   /bootstrap/fshost/blobfs/decompressor
   /bootstrap/fshost/minfs
   /bootstrap/pkg-cache
   /bootstrap/power_manager
   ...
 ```

 ### Inspecting a component

 You can use the `component show` command to get detailed information about a specific
 component.

 `component show` allows partial matching on URL, moniker and component instance ID.

 The following command will display information about the `/core/network/dhcpd` component:

 ```none
 $ fx ffx component show dhcpd
                Moniker:  /core/network/dhcpd
                    URL:  #meta/dhcpv4_server.cm
            Instance ID:  20b2c7aba6793929c252d4e933b8a1537f7bfe8e208ad228c50a896a18b2c4b5
                   Type:  CML Component
        Component State:  Resolved
  Incoming Capabilities:  /svc/fuchsia.net.name.Lookup
                          /svc/fuchsia.posix.socket.packet.Provider
                          /svc/fuchsia.posix.socket.Provider
                          /svc/fuchsia.stash.SecureStore
                          /svc/fuchsia.logger.LogSink
   Exposed Capabilities:  fuchsia.net.dhcp.Server
            Merkle root:  521109a2059e15acc93bf77cd20546d106dfb625f2d1a1105bb71a5e5ea6b3ca
        Execution State:  Running
           Start reason:  '/core/network/netcfg' requested capability 'fuchsia.net.dhcp.Server'
          Running since:  2022-09-15 16:07:48.469094140 UTC
                 Job ID:  28641
             Process ID:  28690
  Outgoing Capabilities:  fuchsia.net.dhcp.Server
 ```

 ### Verifying capability routes

 You can use the `component doctor` command to verify that all capabilities
 exposed and used by a component are successfully routed.

 For example:

 ```none
 $ fx ffx component doctor /bootstrap/archivist
 Querying component manager for /bootstrap/archivist
 URL: fuchsia-boot:///#meta/archivist.cm
 Instance ID: None

       Used Capability                      Error
  [✓]  fuchsia.boot.ReadOnlyLog             N/A
  [✓]  fuchsia.boot.WriteOnlyLog            N/A
  [✓]  fuchsia.component.DetectBinder       N/A
  [✓]  fuchsia.component.KcounterBinder     N/A
  [✓]  fuchsia.component.PersistenceBinder  N/A
  [✓]  fuchsia.component.SamplerBinder      N/A
  [✓]  fuchsia.sys.internal.ComponentEvent  N/A
       Provider
  [✓]  fuchsia.sys.internal.LogConnector    N/A
  [✓]  config-data                          N/A

       Exposed Capability                   Error
  [✓]  fuchsia.diagnostics.FeedbackArchive  N/A
       Accessor
  [✓]  fuchsia.diagnostics.LegacyMetricsAr  N/A
       chiveAccessor
  [✓]  fuchsia.diagnostics.LoWPANArchiveAc  N/A
       cessor
  [✓]  diagnostics                          N/A
  [✓]  fuchsia.diagnostics.ArchiveAccessor  N/A
  [✓]  fuchsia.diagnostics.LogSettings      N/A
  [✓]  fuchsia.logger.Log                   N/A
  [✓]  fuchsia.logger.LogSink               N/A
 ```

 ```none
 $ fx ffx component doctor /core/feedback
 Querying component manager for /core/feedback
 URL: fuchsia-pkg://fuchsia.com/forensics#meta/feedback.cm
 Instance ID: eb345fb7dcaa4260ee0c65bb73ef0ec5341b15a4f603f358d6631c4be6bf7080

       Used Capability                      Error
  [✓]  fuchsia.boot.ReadOnlyLog             N/A
  [✓]  fuchsia.boot.WriteOnlyLog            N/A
  [✓]  fuchsia.diagnostics.FeedbackArchive  N/A
       Accessor
  [✓]  fuchsia.hardware.power.statecontrol  N/A
       .RebootMethodsWatcherRegister
  [✓]  fuchsia.hwinfo.Board                 N/A
  [✓]  fuchsia.hwinfo.Product               N/A
  [✓]  fuchsia.metrics.MetricEventLoggerFa  N/A
       ctory
  [✓]  fuchsia.net.http.Loader              N/A
  [✓]  fuchsia.process.Launcher             N/A
  [✓]  fuchsia.sysinfo.SysInfo              N/A
  [✓]  fuchsia.ui.activity.Provider         N/A
  [✗]  fuchsia.feedback.DeviceIdProvider    `/core/feedback` tried to use `fuchsia.feedback.DeviceIdProvider` from its parent,
                                            but the parent does not offer that capability. Note, use clauses in CML default to
                                            using from parent.
  ...
 ```

 ### Running a component

 The `component run` command can create and launch components in a given isolated collection.

 Note: `fx serve` must be running in order to run a package that is not
 [in base or cached](/docs/development/build/build_system/boards_and_products.md#dependency_sets).

 Here's an example of running the Rust `hello-world` component in the `/core/ffx-laboratory`
 collection. First, you'll need the hello-world package in your universe:

 ```none
 $ fx set <product>.<board> --with //examples/hello_world/rust:hello-world-rust && fx build
 ...
 ```

 Then use the `component run` command to create and launch a component instance from the URL
 `fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm` with the moniker
 `/core/ffx-laboratory:hello-world-rust`:

 ```none
 $ fx ffx component run /core/ffx-laboratory:hello-world-rust fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
 URL: fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
 Moniker: /core/ffx-laboratory:hello-world-rust
 Creating component instance...
 ...
 $ fx ffx component show hello-world-rust
                Moniker: /core/ffx-laboratory:hello-world-rust
                    URL: fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
                   Type: v2 dynamic component
        Execution State: Running
                 Job ID: 50775
             Process ID: 50819
 ...
 ```

 ## Resolving connectivity issues

 If you're experiencing problems communicating with a target device using `ffx`,
 you can use the `doctor` command to diagnose and attempt to resolve them. If you
 file a bug that involves a target device, we'll typically ask for the output
 from `ffx doctor` to provide information about where the problem is.

 `doctor` will attempt to communicate with the ffx daemon, killing
 and restarting it if needed. If this is successful, it will attempt to SSH into
 a target device and start the Remote Control Service.

 If you try running `ffx doctor` under normal circumstances, you should see:

 ```none
 $ fx ffx doctor
 Checking for a running daemon...none running.
 Attempting to kill any zombie daemons...killed at least one daemon.
 Starting a new daemon instance...success
 Attempting to connect to the daemon. This may take a couple seconds...success
 Attempting to communicate with the daemon...success
 Attempting to list targets...success
 Attempting to get an RCS connection...success
 Attempting to communicate with RCS...success


 SUCCESS. You should be able to run ffx commands now.
 ```

 If `doctor` fails, it will try to suggest a resolution to the problem. You can [file a bug](https://issues.fuchsia.dev/issues/new?component=1378294&template=1838957) for the ffx team if you
 persistently have problems. For example, if `doctor` is unable to start the RCS,
 you would see the following:

 ```none
 $ fx ffx doctor
 Checking for a running daemon...found
 Attempting to connect to the daemon. This may take a couple seconds...success
 Attempting to communicate with the daemon...success
 Attempting to list targets...success
 Attempting to get an RCS connection...success
 Attempting to communicate with RCS...FAILED. Timed out.


 Attempt 2 of 3
 Attempting to list targets...success
 Attempting to get an RCS connection...success
 Attempting to communicate with RCS...FAILED. Timed out.


 Attempt 3 of 3
 Attempting to list targets...success
 Attempting to get an RCS connection...success
 Attempting to communicate with RCS...FAILED. Timed out.


 Connecting to RCS failed after maximum attempts. To resolve this issue, try
 rebooting your device. If this persists, please file a bug at the link below
 and include 1) all output
 above and 2) device syslog if available.Bug link: ...
 ```

 ## Testing with ffx

 The `ffx` command is useful when writing integration tests which need to interact
 with the Fuchsia environment. However, since `ffx` is primarily designed for
 developers, it inspects the current environment for configuration and also starts
 a daemon in the background to coordinate communication with Fuchsia devices. This
 makes it more complex to write automated tests that use `ffx` since the configuration
 and daemon should be isolated in order to avoid side effects, or interference from
 the global environment.

 To achieve this isolation, test authors need to use [isolate directories][isolate-dir]
 when running tests which use `ffx`.

 ## Next steps

 - Please provide feedback on this doc by [reaching out to the ffx team](#contacting_the_ffx_team)!
 - Learn how to [extend `ffx`](/docs/development/tools/ffx/development/plugins.md).


 <!-- Reference links -->

 [isolate-dir]: development/integration_testing/README.md
	# Getting started with ffx

	This doc will guide you through some of the features of `ffx`. For an overview
	of the design and components of `ffx`, see [the ffx overview](/docs/development/tools/ffx/overview.md).

	## Contacting the ffx team

	If you discover possible bugs or have questions or suggestions,
	[file a bug](https://issues.fuchsia.dev/issues/new?component=1378294&template=1838957).

	## Prerequisites

	To follow the examples in this doc, you'll need a Fuchsia device running. If you
	don't have a physical device connected, you can use an emulator.

	To start an emulator with networking enabled but without graphical user
	interface support, run `ffx emu start --headless`.

	For more information on configuring the emulator
	see, [Start the Fuchsia emulator](/docs/get-started/set_up_femu.md).

	Your device must be running a `core`
	[product configuration](/docs/development/build/build_system/boards_and_products.md)
	or a product configuration that extends `core` (such as `workstation_eng`).

	Optionally, you can run `ffx log`, which will provide some additional information
	about the interactions between `ffx` and your Fuchsia target device.

	## Introduction

	After following all the prerequisites, run the following in a terminal:

	```posix-terminal
	fx ffx help
	```

	This will list all of the available `ffx` subcommands. You'll see something
	like:

	```none
	Usage: ffx [-c <config>] [-e <env>] [-t <target>] [<command>] [<args>]

	Fuchsia's developer tool

	Options:
	-c, --config override default configuration
	-e, --env override default environment settings
	-t, --target apply operations across single or multiple targets
	--help display usage information

	Commands:
	component Discover and manage components
	config View and switch default and user configurations
	daemon Interact with/control the ffx daemon
	diagnostic Run diagnostic tests on Fuchsia targets
	docs View suite of docs for ffx and for Fuchsia
	doctor Run common checks for the ffx tool and host environment
	emulator Start and manage Fuchsia emulators
	overnet Interact with the Overnet mesh
	package Create and publish Fuchsia packages
	sdk Modify or query the installed SDKs
	target Interact with a target device or emulator
	vendor Run partner plugins
	version Print out ffx tool and daemon versions
	```

	You can use `fx ffx help <subcommand>` or `fx ffx <subcommand> --help` to see
	more about any subcommand.

	## Interacting with target devices

	In a terminal, run the following:

	```posix-terminal
	fx ffx target list
	```

	You'll see a list of devices that `ffx` has discovered. For example, with a
	single emulator running, output looks like:

	```none
	NAME SERIAL TYPE STATE ADDRS/IP RCS
	fuchsia-emulator <unknown> Unknown Product [fe80::5054:ff:fe63:5e7a%4] N
	```

	`RCS`: Indicates whether there is a reachable instance of the Remote Control
	Service (RCS) running on the device.

	In order to get `ffx` to automatically connect to a device, you must either have
	set the target's nodename to be the default target, or attempt to interact with the
	device.

	To set the target to be the default, run:

	```posix-terminal
	fx ffx target default set $NODENAME
	```

	If the default target has been set prior to starting the daemon, waiting a few seconds
	should yield a change to the `RCS` status to show `Y`.

	If the default target has been set after starting the daemon, attempting to interact
	with the target should be sufficient to kick off a connection, like the following

	```posix-terminal
	fx ffx component list
	```

	Note: If the default target has been set, and you are unable to run that command
	against the target, [reach out](#contacting_the_ffx_team) to the `ffx` team.

	Then the next time you list targets you should see that an `RCS` connection
	is active.

	```none
	$ fx ffx target list
	NAME SERIAL TYPE STATE ADDRS/IP RCS
	fuchsia-emulator <unknown> Unknown Product [fe80::5054:ff:fe63:5e7a%4] Y
	```

	If a target has been set as default there will be a `*` next to it.

	If you had `ffx log` running, you should also see something like the following in
	the logs:

	```none
	[00009.776170][28540][28542][remote-control, remote_control_bin] INFO: published remote control service to overnet
	```

	NOTE: if the `RCS` column remains `N` for an extended amount of time and you have
	already set this target's nodename to `target.default` _before_ initially starting
	ffx, [reach out](#contacting_the_ffx_team) to the `ffx` team.

	### On Default Targets

	Above we covered setting the default target using the command

	```posix-terminal
	fx ffx target default set
	```

	It is also possible to set the default target on a per-command basis using the
	`--target` flag like so.

	```posix-terminal
	fx ffx --target $NODENAME component list
	```

	### Interacting with multiple devices

	TODO: fill this out.

	### Controlling the state of target devices

	You can use the `target off` and `target reboot` subcommands to power-off or
	reboot a device, respectively.

	## Configuration

	See documentation for the [config command](/docs/development/tools/ffx/commands/config.md).

	## Interacting with Components

	### Monikers

	Many `ffx` commands that use components take monikers as a parameter. You can read more about
	monikers and their syntax in [component moniker documentation](/docs/reference/components/moniker.md).

	### Finding components

	The `component list` command will output monikers of all components that currently exist
	in the component topology.

	```none
	$ fx ffx component list
	/
	/bootstrap
	/bootstrap/archivist
	/bootstrap/base_resolver
	/bootstrap/console
	/bootstrap/console-launcher
	/bootstrap/cr50_agent
	/bootstrap/device_name_provider
	/bootstrap/driver_index
	/bootstrap/driver_manager
	/bootstrap/flashmap
	/bootstrap/fshost
	/bootstrap/fshost/blobfs
	/bootstrap/fshost/blobfs/decompressor
	...
	```

	You can use the `component select capability` command to search for components that use/expose
	a capability with a given name.

	The following command will display all components that use/expose the `diagnostics` capability:

	```none
	$ fx ffx component capability diagnostics
	Exposed:
	/bootstrap/archivist
	/bootstrap/base_resolver
	/bootstrap/driver_manager
	/bootstrap/fshost
	/bootstrap/fshost/blobfs
	/bootstrap/fshost/blobfs/decompressor
	/bootstrap/fshost/minfs
	/bootstrap/pkg-cache
	/bootstrap/power_manager
	...
	```

	### Inspecting a component

	You can use the `component show` command to get detailed information about a specific
	component.

	`component show` allows partial matching on URL, moniker and component instance ID.

	The following command will display information about the `/core/network/dhcpd` component:

	```none
	$ fx ffx component show dhcpd
	Moniker: /core/network/dhcpd
	URL: #meta/dhcpv4_server.cm
	Instance ID: 20b2c7aba6793929c252d4e933b8a1537f7bfe8e208ad228c50a896a18b2c4b5
	Type: CML Component
	Component State: Resolved
	Incoming Capabilities: /svc/fuchsia.net.name.Lookup
	/svc/fuchsia.posix.socket.packet.Provider
	/svc/fuchsia.posix.socket.Provider
	/svc/fuchsia.stash.SecureStore
	/svc/fuchsia.logger.LogSink
	Exposed Capabilities: fuchsia.net.dhcp.Server
	Merkle root: 521109a2059e15acc93bf77cd20546d106dfb625f2d1a1105bb71a5e5ea6b3ca
	Execution State: Running
	Start reason: '/core/network/netcfg' requested capability 'fuchsia.net.dhcp.Server'
	Running since: 2022-09-15 16:07:48.469094140 UTC
	Job ID: 28641
	Process ID: 28690
	Outgoing Capabilities: fuchsia.net.dhcp.Server
	```

	### Verifying capability routes

	You can use the `component doctor` command to verify that all capabilities
	exposed and used by a component are successfully routed.

	For example:

	```none
	$ fx ffx component doctor /bootstrap/archivist
	Querying component manager for /bootstrap/archivist
	URL: fuchsia-boot:///#meta/archivist.cm
	Instance ID: None

	Used Capability Error
	[✓] fuchsia.boot.ReadOnlyLog N/A
	[✓] fuchsia.boot.WriteOnlyLog N/A
	[✓] fuchsia.component.DetectBinder N/A
	[✓] fuchsia.component.KcounterBinder N/A
	[✓] fuchsia.component.PersistenceBinder N/A
	[✓] fuchsia.component.SamplerBinder N/A
	[✓] fuchsia.sys.internal.ComponentEvent N/A
	Provider
	[✓] fuchsia.sys.internal.LogConnector N/A
	[✓] config-data N/A

	Exposed Capability Error
	[✓] fuchsia.diagnostics.FeedbackArchive N/A
	Accessor
	[✓] fuchsia.diagnostics.LegacyMetricsAr N/A
	chiveAccessor
	[✓] fuchsia.diagnostics.LoWPANArchiveAc N/A
	cessor
	[✓] diagnostics N/A
	[✓] fuchsia.diagnostics.ArchiveAccessor N/A
	[✓] fuchsia.diagnostics.LogSettings N/A
	[✓] fuchsia.logger.Log N/A
	[✓] fuchsia.logger.LogSink N/A
	```

	```none
	$ fx ffx component doctor /core/feedback
	Querying component manager for /core/feedback
	URL: fuchsia-pkg://fuchsia.com/forensics#meta/feedback.cm
	Instance ID: eb345fb7dcaa4260ee0c65bb73ef0ec5341b15a4f603f358d6631c4be6bf7080

	Used Capability Error
	[✓] fuchsia.boot.ReadOnlyLog N/A
	[✓] fuchsia.boot.WriteOnlyLog N/A
	[✓] fuchsia.diagnostics.FeedbackArchive N/A
	Accessor
	[✓] fuchsia.hardware.power.statecontrol N/A
	.RebootMethodsWatcherRegister
	[✓] fuchsia.hwinfo.Board N/A
	[✓] fuchsia.hwinfo.Product N/A
	[✓] fuchsia.metrics.MetricEventLoggerFa N/A
	ctory
	[✓] fuchsia.net.http.Loader N/A
	[✓] fuchsia.process.Launcher N/A
	[✓] fuchsia.sysinfo.SysInfo N/A
	[✓] fuchsia.ui.activity.Provider N/A
	[✗] fuchsia.feedback.DeviceIdProvider `/core/feedback` tried to use `fuchsia.feedback.DeviceIdProvider` from its parent,
	but the parent does not offer that capability. Note, use clauses in CML default to
	using from parent.
	...
	```

	### Running a component

	The `component run` command can create and launch components in a given isolated collection.

	Note: `fx serve` must be running in order to run a package that is not
	[in base or cached](/docs/development/build/build_system/boards_and_products.md#dependency_sets).

	Here's an example of running the Rust `hello-world` component in the `/core/ffx-laboratory`
	collection. First, you'll need the hello-world package in your universe:

	```none
	$ fx set <product>.<board> --with //examples/hello_world/rust:hello-world-rust && fx build
	...
	```

	Then use the `component run` command to create and launch a component instance from the URL
	`fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm` with the moniker
	`/core/ffx-laboratory:hello-world-rust`:

	```none
	$ fx ffx component run /core/ffx-laboratory:hello-world-rust fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
	URL: fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
	Moniker: /core/ffx-laboratory:hello-world-rust
	Creating component instance...
	...
	$ fx ffx component show hello-world-rust
	Moniker: /core/ffx-laboratory:hello-world-rust
	URL: fuchsia-pkg://fuchsia.com/hello-world-rust#meta/hello-world-rust.cm
	Type: v2 dynamic component
	Execution State: Running
	Job ID: 50775
	Process ID: 50819
	...
	```

	## Resolving connectivity issues

	If you're experiencing problems communicating with a target device using `ffx`,
	you can use the `doctor` command to diagnose and attempt to resolve them. If you
	file a bug that involves a target device, we'll typically ask for the output
	from `ffx doctor` to provide information about where the problem is.

	`doctor` will attempt to communicate with the ffx daemon, killing
	and restarting it if needed. If this is successful, it will attempt to SSH into
	a target device and start the Remote Control Service.

	If you try running `ffx doctor` under normal circumstances, you should see:

	```none
	$ fx ffx doctor
	Checking for a running daemon...none running.
	Attempting to kill any zombie daemons...killed at least one daemon.
	Starting a new daemon instance...success
	Attempting to connect to the daemon. This may take a couple seconds...success
	Attempting to communicate with the daemon...success
	Attempting to list targets...success
	Attempting to get an RCS connection...success
	Attempting to communicate with RCS...success


	SUCCESS. You should be able to run ffx commands now.
	```

	If `doctor` fails, it will try to suggest a resolution to the problem. You can [file a bug](https://issues.fuchsia.dev/issues/new?component=1378294&template=1838957) for the ffx team if you
	persistently have problems. For example, if `doctor` is unable to start the RCS,
	you would see the following:

	```none
	$ fx ffx doctor
	Checking for a running daemon...found
	Attempting to connect to the daemon. This may take a couple seconds...success
	Attempting to communicate with the daemon...success
	Attempting to list targets...success
	Attempting to get an RCS connection...success
	Attempting to communicate with RCS...FAILED. Timed out.


	Attempt 2 of 3
	Attempting to list targets...success
	Attempting to get an RCS connection...success
	Attempting to communicate with RCS...FAILED. Timed out.


	Attempt 3 of 3
	Attempting to list targets...success
	Attempting to get an RCS connection...success
	Attempting to communicate with RCS...FAILED. Timed out.


	Connecting to RCS failed after maximum attempts. To resolve this issue, try
	rebooting your device. If this persists, please file a bug at the link below
	and include 1) all output
	above and 2) device syslog if available.Bug link: ...
	```

	## Testing with ffx

	The `ffx` command is useful when writing integration tests which need to interact
	with the Fuchsia environment. However, since `ffx` is primarily designed for
	developers, it inspects the current environment for configuration and also starts
	a daemon in the background to coordinate communication with Fuchsia devices. This
	makes it more complex to write automated tests that use `ffx` since the configuration
	and daemon should be isolated in order to avoid side effects, or interference from
	the global environment.

	To achieve this isolation, test authors need to use [isolate directories][isolate-dir]
	when running tests which use `ffx`.

	## Next steps

	- Please provide feedback on this doc by [reaching out to the ffx team](#contacting_the_ffx_team)!
	- Learn how to [extend `ffx`](/docs/development/tools/ffx/development/plugins.md).


	<!-- Reference links -->

	[isolate-dir]: development/integration_testing/README.md