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authorVinod Ahuja <vahuja@unomaha.edu>2022-09-12 17:22:20 -0500
committerJan-Simon Moeller <jsmoeller@linuxfoundation.org>2022-09-22 10:25:01 +0000
commit0a3b4ca17dd1eeab7f15cdfb590656377c996501 (patch)
tree62b18710e7c91241df6d75a78cd8ccca8bd57717 /docs/3_Developer_Guides/2_Creating_a_New_Service.md
parent33a52a1334bf135529b9308a5a2de06377eafea7 (diff)
Improving Developer 3_Developer_Guides
Worked on creating new services and applications. 1. Removed Fixme file 2. Formatted some text and numbering 3. Fixed some broken links. Bug-AGL: [SPEC-4470] Signed-off-by: Vinod Ahuja <vahuja@unomaha.edu> Change-Id: If3f9a171faff8466bd6d141f9537cd98468fadbb Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/documentation/+/27993 Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org> Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
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.md24
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:
```