Guide to Configuring the Modular Framework
Note: The Modular framework is being deprecated in favor of the Session Framework.
Requirements
To configure the modular framework, you will need to create a JSON file defining
the required configurations for basemgr and sessionmgr as detailed below.
The configuration file should be packaged via the build rule modular_config,
which will validate your file against a schema. You must then include the
modular_config() target in the product's base packages.
The file may contain (non-standard JSON) C-style comments
(/* block */ and // inline).
Reading configuration
The configuration provided to basemgr is available through
the [component inspection][docs-inspect] of the basemgr and
sessionmgr components.
Use [ffx inspect][ffx-inspect] to query the configuration
of a running basemgr:
Use [ffx inspect][ffx-inspect] to query the configuration
of a running sessionmgr:
Example
{
/* This is a block comment.
Comments are ignored. */
// This is an inline comment. Comments are ignored.
"basemgr": {
"enable_cobalt": false,
"use_session_shell_for_story_shell_factory": true,
"session_shells": [
{
"url": "fuchsia-pkg://fuchsia.com/dev_session_shell#meta/dev_session_shell.cmx",
}
]
},
"sessionmgr": {
"startup_agents": [
"fuchsia-pkg://fuchsia.com/startup_agent#meta/startup_agent.cmx"
],
"session_agents": [
"fuchsia-pkg://fuchsia.com/session_agent#meta/session_agent.cmx"
],
"component_args": [
{
"uri": "fuchsia-pkg://fuchsia.com/startup_agent#meta/startup_agent.cmx",
"args": [ "--foo", "--bar=true" ]
}
],
"agent_service_index": [
{
"service_name": "fuchsia.modular.SomeServiceName",
"agent_url": "fuchsia-pkg://fuchsia.com/some_agent#meta/some_agent.cmx"
}
],
"restart_session_on_agent_crash": [
"fuchsia-pkg://fuchsia.com/some_agent#meta/some_agent.cmx"
]
}
}
Basemgr fields
session_shellsarray (optional)- List of exactly one session shell containing the following
fields (is an Array type for backwards compatibility):
url: string (required)- The fuchsia component url for which session shell to use.
- default: A single session shell with the following properties:
url:fuchsia-pkg://fuchsia.com/dev_story_shell#meta/dev_session_shell.cmx
story_shell_url: string (optional)- The fuchsia component url for which story shell to use.
- default:
fuchsia-pkg://fuchsia.com/dev_story_shell#meta/dev_story_shell.cmx enable_cobalt: boolean (optional)- When set to false, Cobalt statistics are disabled.
- default:
true use_session_shell_for_story_shell_factory: boolean (optional)- Create story shells through StoryShellFactory exposed by the session shell
instead of creating separate story shell components. When set,
story_shell_urland any story shell args are ignored. - default:
false
Sessionmgr fields
enable_cobalt: boolean (optional)- When set to false, Cobalt statistics are disabled. This is used for testing.
- default:
true startup_agents: string[] (optional)- A list of fuchsia component urls that specify which agents to launch at startup.
session_agents: string[] (optional)- A list of fuchsia component urls that specify which agents to launch at startup with PuppetMaster and FocusProvider services.
component_args: array (optional)- A list of key/value pairs to construct a map from component URI to
arguments list for that component. Presence in this list results in the
given arguments passed to the component as its argv at launch.
uri: The component's uri.args: A list of arguments to be passed to the component specified byuri. Arguments must be prefixed with --.
agent_service_index: array (optional)- A list of key/value pairs mapping from service name to the serving component's
URL. Agents and the session shell are both valid components to specify
here. Service names must be unique: only one component can provide any
given service. These services are provided to modules, the session shell,
and agents, in their namespace (i.e. at the path
"/svc/fully.qualified.ServiceName").
service_name: The name of a service offered byagent_url.agent_url: A fuchsia component url that specifies which agent/shell will provide the named service.
restart_session_on_agent_crash: array (optional)-
A list of agent URLs that will cause the session to be restarted when they terminate unexpectedly. If an agent is not in this list, sessionmgr will restart it individually, preserving the session.
The session shell is automatically added to this list. -
disable_agent_restart_on_crash: boolean (optional) - When set to true, disables any automatic restarts of agents listed insession_agentsif they crash. - default:false
docs-inspect[ffx-inspect]: https://fuchsia.dev/reference/tools/sdk/ffx.md#inspect