Netemul Runner is a set of components that allow creating hermetic test environments for integration tests.
Besides creating sandboxed and hermetic environments, Netemul provides a set of services that allow for quick and easy network emulation that can be used to manage virtual networks between sandboxed environments. The hermetic environments with the virtual networks between them can be used to emulate multiple fuchsia devices talking to each other over networks and, thus, allows for self-contained integration tests.
Two components are provided netemul_runner
and netemul_sandbox
:
netemul_runner
can be used as a runner, as defined by the component framework, and provides the FIDL service fuchsia.sys.Runner. It expects the program.data
field of your test component's cmx
manifest to point to another cmx
file within the same component package.
netemul_sandbox
is responsible for creating sandboxed environments that can be configured to run integration tests. netemul_sandbox
has two modes of operation: enclosing process or service provider, and it is selected based on its command-line arguments.
In enclosing process mode, netemul_sandbox
receives a component as a fuchsia package url as a command-line argument and proceeds to create a hermetic environment and then launch the provided component within it. The exit code of the netemul_sandbox
process will mimic the component‘s. When using enclosing process, clients will typically setup a layout for the test using the netemul (facet)[#facet] in the component-under-test’s cmx manifest.
In service provider mode, netemul_sandbox
will expose the fuchsia.netemul.sandbox.Sandbox protocol that allows users to create netemul's managed environments or run full sandboxes from components.
In sum, users have two options to use netemul for a given component under test:
netemul_runner
, which will use netemul_sandbox
in enclosing process mode and spawn the component under test within a netemul environment. See Runner sample setup for an example of how to run a component like this.netemul_sandbox
as a service provider injected into the component under test's environment by using the standard fuchsia.test
facet. The component under test can then simply use the provided fuchsia.netemul.sandbox.Sandbox service to spawn and control hermetic environments and emulated networks.To have a test run on the sandbox, you'll typically use the following pattern:
test_package
.cmx
files:[my_component].cmx
, where my_component is the component you want to run inside the hermetic environment. It should be indistinguishable from a regular component manifest. You can run multiple different components inside a netemul environment by simply using their package url. For this example, though, we'll only have the one [my_component].cmx
.[my_test].cmx
, in turn will contain a fuchsia.netemul
facet that defines what environments to create and which tests to run and, also, will tell the component launcher to use netemul
to run it:{ "program": { "binary": "bin/app" }, "runner": "fuchsia-pkg://fuchsia.com/netemul_runner", "facets" : { "fuchsia.netemul" : { "environment" : { "test" : [{"url" : "fuchsia-pkg://fuchsia.com/my_component#meta/my_component.cmx"}] } } } }
netemul_sandbox
's tests use the pattern thoroughly and can be a good source of examples.
Note 1: the bin/app
entry is just there to match the manifest schema, it is not used nor points to anything of importance.
Note 2: Make sure to match the build file pattern used here for tests that are defined solely by a cmx manifest, otherwise you risk your test being enumerated by the integration test framework.
If your component under test doesn‘t need to (or shouldn’t) be inside a netemul environment, you can use the fuchsia.netemul.sandbox.Sandbox service by injecting it into your test component‘s environment. Your component’s cmx manifest will look like:
{ "facets": { "fuchsia.test": { "injected-services": { "fuchsia.netemul.sandbox.Sandbox": "fuchsia-pkg://fuchsia.com/netemul_sandbox#meta/netemul_sandbox.cmx" } } }, "program": { "binary": "test/my_test" }, "sandbox": { "services": [ "fuchsia.netemul.sandbox.Sandbox" ] } }
The fuchsia.test
facet when run by run_test_component
(the standard way of running tests) will spawn an instance of the sandbox service for use by the component under test.
A rust example of how to use the sandbox service can be found here.
The sandboxed environments created by netemul_sandbox
will always contain the following FIDL services that can be used to manipulate and configure the environment. Just don't forget to add them to your .cmx
's sandbox parameters to have access.
netemul_sandbox
creates a single NetworkContext instance (see fuchsia.netemul.network) and makes it available to all environments that are created under it. That is to say, NetworkContext intentionally breaks hermeticity. This service is the core motivator behind Netemul Runner, as it is able to create virtual networks that can be used to connect different hermetic test environments.
A valid pattern is to have a root environment configure the network setup and then spawn children to use it or, alternatively, the virtual networks can be setup using the configuration facet.
Every environment in the sandbox will be exposed to the service fuchsia.netemul.environment.ManagedEnvironment. You can use the provided service to launch other child environments (which may or may not inherit settings). Every managed environment is completely hermetic from a services perspective, apart from basic configuration that may be inherited. If you wish to have service inheritance in your spawned children environments, refer to fuchsia.sys.Environment. In other words, managed environments never inherit their parent‘s services in the same sense as fuchsia.sys.Environment does, that is, inheriting the same instance of a service. Rather, managed environments may optionally inherit their parent’s service configuration, that is, the configuration of which services to launch in the environment.
The ManagedEnvironment service also provides a special fuchsia.sys.Launcher instance that provides extended functionality, such as forwarding VirtualDevice instances in a /vdev
path and mounting a memfs under /vdata
for components that request dev and isolated-persistent-storage, respectively.
VirtualDevice instances are a vfs
hook for NetworkContext's Endpoints. That allows for clients to expose specific Endpoints on the vfs
under the created root folder /vdev
. This feature is used to test components that perform vfs
scanning to retrieve devices with minimal intrusion. This is used to go around the limitation that /dev
is never hermetic to sandboxed environments.
The ManagedEnvironment also provides hermetic fuchsia.logger.LogSink and fuchsia.logger.Log services so that environments can run components that use syslog. Users have the ability to enable and customize log printing from syslog -- they can also completely disable syslog outputs. See LoggerOptions for more information. If enabled, log prints will be tagged with the environment name and printed to stdout.
Along the same lines as NetworkContext, netemul_sandbox
creates a single Syncmanager instance (see fuchsia.netemul.sync) that is shared between all created environments. Clients can (and are encouraged to) use the Bus service or the other provided primitives to synchronize multiple test agents that are spawned across different environments.
For example (see easy_nestack_cfg test for working code), a test that creates a TCP server on one environment and a client on another is encouraged to use the Bus service to have the server communicate with the client out-of-band first and ensure it's actually ready to listen for incoming connections.
netemul_sandbox
will look for the facet fuchsia.netemul on the .cmx
file your provide to it. The facet can be used to build and configure the testing environment before your code gets called, thus decreasing the amount of boilerplate setup for every test.
Below is the documentation of the objects accepted. The root object is of type Config
Field | Type | Description |
---|---|---|
default_url | String | Global default URL, will be used by any instance of LaunchArgs |
disabled | Boolean | if true, no tests or environments will be created and sandbox will exit cleanly. defaults to false |
timeout | Number | Optional global timeout for all tests to complete, in seconds. |
capture | String or Boolean | Capture network traffic on emulated networks. See below for possible values. Defaults to "NO" |
environment | Environment | root environment configuration |
networks | Array of Network | collection of networks to setup |
capture
values:
"ALWAYS"
will always generate network dumps once sandbox exits."ON_ERROR"
will only generate dumps if the suite failed for any reason. Same as true
."NO"
disables capturing. Same as false
.Network dumps are captured as pcap
files and printed hex-encoded to STDOUT
at the end of the test run. You can save the dump in hex format and then convert it to binary with xxd -r -p [hexdata]
.
Field | Type | Description |
---|---|---|
name | String | environment's name, for debugging |
services | Dictionary of LaunchArgs | Collection of services. Dictionary keys are the service's name and value contains launch information. |
children | Array of Environment | Collection of child environments to spawn. |
devices | Array of String | Collection of endpoint names to attach to environment as VirtualDevices. Endpoints will be available under /vdev/class/ethernet/[endpoint_name] for every component launched by the cmx facet or with this environment's ManagedLauncher. |
test | Array of LaunchArgs | Collection of test processes. A test process will have its exit code monitored. If any test fails, the sandbox exits immediately and copies the return code. Otherwise, the sandbox will only exit when ALL tests have exited successfully |
apps | Array of LaunchArgs | Collection of applications to run. An application is spawned into the environment asynchronously and the sandbox doesn't care about its exit status. |
setup | Array of LaunchArgs | Collection of setup processes to run. Setup processes will run sequentially and synchronously (sandbox waits for it to exit successfully) before the tests are executed. Any setup process that fails will cause the sandbox to exit with a failure status. |
inherit_services | Boolean | Whether to inherit the parent environment's service configuration. Defaults to true. |
logger_options | LoggerOptions | Options for environment specific logger. |
Note: Launch args can always just be specified as a String value. In that case, it's as if only the url field had been specified.
Field | Type | Description |
---|---|---|
url | String | Fuchsia package URL to launch. Only valid package URLs will be accepted. If empty or not present, will default to the value of Config's default_url . |
arguments | Array of String | Command-line arguments to pass to process. |
Field | Type | Description |
---|---|---|
name | String | Required network name identifier. Must be unique. |
endpoints | Array of Endpoint | Collection of endpoints to be created and attached to the network. |
Field | Type | Description |
---|---|---|
name | String | Required endpoint name identifier. Must be unique in even across networks. |
mac | String | MAC address of virtual endpoint. If not set will be generated randomly using the endpoint's name as seed. |
mtu | Number | Endpoint's MTU. Defaults to 1500. |
up | Boolean | Toggle endpoint to link up as part of setup process. Defaults to true. |
Field | Type | Description |
---|---|---|
enabled | Boolean | Enable the logger (default: true) |
klogs_enabled | Boolean | Enable printing kernel logs (default: false) |
filters | LoggerFilterOptions | Options for log filterering |
Field | Type | Description |
---|---|---|
verbosity | Integer | Log verbosity level (default: 0) |
tags | Array of Strings | Tags required to show log (empty array means no filters on tags) (default: []) |
netemul_sandbox
provides helpers that can be launched in sandboxed environments to perform common operations.
The netstack_cfg
helper is a CLI-like tool that uses the NetworkContext service to retrieve emulated endpoints and attach them to netstack instances in an emulated environment. You can launch it by using its package url: fuchsia-pkg://fuchsia.com/netemul_sandbox#meta/helper_netstack_cfg.cmx
. It receives the command line arguments shown below and is typically used as a “setup” process in an environment's facet definition.
netstack_cfg Configure netstack from emulated environments. USAGE: netstack_cfg [FLAGS] [OPTIONS] -e <endpoint> FLAGS: -h, --help Prints help information --skip-up-check netstack_cfg will by default wait until it sees the interface be reported as "Up", skip-up- check will override that behavior. -V, --version Prints version information OPTIONS: -e <endpoint> Endpoint name to retrieve from network.EndpointManager -i <ip> Static ip address to assign (don't forget /prefix termination). Omit to use DHCP.
The mock_device_settings
helper is a mock implementation of the FIDL protocol fuchsia.devicesettings.DeviceSettingsManager
. You can launch it by using its package url: fuchsia-pkg://fuchsia.com/netemul_sandbox#meta/mock_device_settings.cmx
. It receives the command line arguments shown below and is intended to be used as a “services” entry in environment's facet definition. You must specify the values for every key that your tests may want to access as a command-line option.
Serves DeviceSettingsManager with a memory-backed database USAGE: mock_device_settings [OPTIONS] FLAGS: -h, --help Prints help information -V, --version Prints version information OPTIONS: -i <int_key>... Starts with a pre-set integer key, format [k]=[v] e.g. Audio=100 -s <string_key>... Starts with a pre-set string key, format [k]=[v] e.g. DeviceName=my-device-name