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Diffstat (limited to 'docs/3_Developer_Guides/2_Creating_a_New_Service.md')
| -rw-r--r-- | docs/3_Developer_Guides/2_Creating_a_New_Service.md | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/docs/3_Developer_Guides/2_Creating_a_New_Service.md b/docs/3_Developer_Guides/2_Creating_a_New_Service.md index 7974d00..0fb2453 100644 --- a/docs/3_Developer_Guides/2_Creating_a_New_Service.md +++ b/docs/3_Developer_Guides/2_Creating_a_New_Service.md @@ -4,10 +4,12 @@ title: Creating a New Service Services are software running in the background and providing, as their name suggests, various services to other software: access to specific system hardware, connectivity -management, network servers... They can be split into 2 categories: -- system services: those usually run as a privileged user and make use of shared system +management, and network servers. Services can be split into 2 categories: + +- **System services:** those usually run as a privileged user and make use of shared system resources which they should have exclusive access to -- user services: such services run as part of an unprivileged user's session and can + +- **User services:** such services run as part of an unprivileged user's session and can only be called by said user # Basic requirements @@ -15,7 +17,9 @@ management, network servers... They can be split into 2 categories: The only mandatory requirement is that service packages provide a `.service` file so they can be properly managed by `systemd`. This file must be installed to a specific location, determined by the service type (system or user): + - `/usr/lib/systemd/system/` for system services + - `/usr/lib/systemd/user/` for user services Below is an example of a simple user service, running in a graphical session and @@ -36,7 +40,7 @@ WantedBy=agl-session.target ``` The `WantedBy=agl-session.target` indicates the service is part of the default AGL -user session, as mentioned in the [Application Framework](1_Application_Framework/1_Introduction/#user-session-management) +user session, as mentioned in the [Application Framework](../1_Application_Framework/1_Introduction/#user-session-management) documentation. The `Restart=on-failure` directive ensures the service will be automatically @@ -65,7 +69,9 @@ ExecStart=/path/to/executable In addition, they must provide a D-Bus service file named `NAME.service` and installed to one of the following locations: + - `/usr/share/dbus-1/system-services` for system services + - `/usr/share/dbus-1/services` for user services The contents of the D-Bus service file must be the following: @@ -95,19 +101,19 @@ executed on system or session startup. System services can take advantage of the Yocto `systemd` class which automates the process of enabling such services. -1. Ensure the recipe inherits from the `systemd` class: +1\. Ensure the recipe inherits from the `systemd` class: ``` inherit systemd ``` -2. Declare the system services that needs to be enabled on boot: +2\. Declare the system services that needs to be enabled on boot: ``` SYSTEMD_SERVICE:${PN} = "NAME.service" ``` -3. Ensure the `FILES` variable includes the systemd service directory the corresponding +3\. Ensure the `FILES` variable includes the systemd service directory the corresponding file will be installed to: ``` @@ -122,7 +128,7 @@ FILES:${PN} = "\ The `systemd` class doesn't provide an equivalent mechanism for user services. This must therefore be done manually as part of the package's install process. -1. Make the service a part of the user session: +1\. Make the service a part of the user session: ``` do_install:append() { @@ -134,7 +140,7 @@ do_install:append() { This ensures `agl-session.target` depends on `NAME.service`, the latter being therefore automatically started on session creation. -2. Ensure the `FILES` variable includes the systemd service directory the corresponding +2\. Ensure the `FILES` variable includes the systemd service directory the corresponding file will be installed to: ``` |