Add SplitArtifacts=appstream-metainfo

GNOME Software parses .metainfo.xml files to provide nice
metadata for artifacts it downloads/updates. Follow the spec
and add parameter for it, filling the content from os-release.

https://www.freedesktop.org/software/appstream/docs/sect-Metadata-OS.html

Author: bluca

mkosi/__init__.py

@@ -26,6 +26,7 @@
 from contextlib import AbstractContextManager
 from pathlib import Path
 from typing import Any, Optional, Union, cast
+from urllib.parse import urlparse
 
 from mkosi.archive import can_extract_tar, extract_tar, make_cpio, make_tar
 from mkosi.bootloader import (
@@ -343,12 +344,14 @@ def check_root_populated(context: Context) -> None:
         )
 
 
-def configure_os_release(context: Context) -> None:
-    """Write IMAGE_ID and IMAGE_VERSION to /usr/lib/os-release in the image."""
+def configure_os_release_and_appstream(context: Context) -> None:
+    """Write os-release and appstream metainfo in the image."""
 
     if context.config.overlay or context.config.output_format.is_extension_image():
         return
 
+    osrelease_content = {}
+
     for candidate in ["usr/lib/os-release", "usr/lib/initrd-release", "etc/os-release"]:
         osrelease = context.root / candidate
 
@@ -385,9 +388,68 @@ def configure_os_release(context: Context) -> None:
 
             newosrelease.rename(osrelease)
 
+        osrelease_content = read_env_file(osrelease)
+
         if ArtifactOutput.os_release in context.config.split_artifacts:
             shutil.copy(osrelease, context.staging / context.config.output_split_os_release)
 
+    # https://www.freedesktop.org/software/appstream/docs/sect-Metadata-OS.html
+    osid = context.config.appstream_id or osrelease_content.get("ID", "linux")
+    name = context.config.appstream_name or osrelease_content.get("NAME") or context.config.image_id or osid
+    if context.config.appstream_description:
+        description = context.config.appstream_description
+    else:
+        description = f"{osrelease_content.get('PRETTY_NAME', 'Image')} built with mkosi"
+    icon = context.config.appstream_icon or "https://brand.systemd.io/assets/svg/systemd-logomark.svg"
+    home_url = context.config.appstream_url or osrelease_content.get("HOME_URL")
+    if home_url:
+        url = urlparse(home_url)
+        if not url.netloc:
+            home_url = None
+    if context.config.appstream_id:
+        id = context.config.appstream_id
+    elif home_url:
+        url = urlparse(home_url)
+        netloc = url.netloc.split(".")
+        netloc.reverse()
+        if "www" in netloc:
+            netloc.remove("www")
+        id = ".".join(netloc)
+        id += f".{osid}"
+    else:
+        id = osid
+    timestamp = (
+        datetime.datetime.fromtimestamp(context.config.source_date_epoch, tz=datetime.timezone.utc)
+        if context.config.source_date_epoch is not None
+        else datetime.datetime.now(tz=datetime.timezone.utc)
+    ).isoformat()
+
+    metainfo = '<?xml version="1.0" encoding="UTF-8"?>\n'
+    metainfo += '<component type="operating-system">\n'
+    metainfo += f"  <id>{id}</id>\n"
+    metainfo += f"  <name>{name}</name>\n"
+    metainfo += f"  <summary>{osid} image built with mkosi</summary>\n"
+    metainfo += f"  <description><p>{description}</p></description>\n"
+    if home_url:
+        metainfo += f'  <url type="homepage">{home_url}</url>\n'
+    if icon:
+        metainfo += f'  <icon type="remote">{icon}</icon>\n'
+    metainfo += "  <metadata_license>FSFAP</metadata_license>\n"
+    metainfo += "  <releases>\n"
+    metainfo += (
+        f'     <release version="{context.config.image_version}" date="{timestamp}" type="development">\n'
+    )
+    metainfo += "       <description></description>\n"
+    metainfo += "     </release>\n"
+    metainfo += "  </releases>\n"
+    metainfo += "</component>\n"
+
+    metainto_out = context.root / f"usr/share/metainfo/{id}.metainfo.xml"
+    metainto_out.parent.mkdir(parents=True, exist_ok=True)
+    metainto_out.write_text(metainfo)
+    if ArtifactOutput.appstream_metainfo in context.config.split_artifacts:
+        (context.staging / context.config.output_split_appstream_metainfo).write_text(metainfo)
+
 
 def configure_extension_release(context: Context) -> None:
     if context.config.output_format not in (OutputFormat.sysext, OutputFormat.confext):
@@ -3921,7 +3983,7 @@ def build_image(context: Context) -> None:
         fixup_vmlinuz_location(context)
 
         configure_autologin(context)
-        configure_os_release(context)
+        configure_os_release_and_appstream(context)
         configure_extension_release(context)
         configure_initrd(context)
         configure_ssh(context)

mkosi/config.py

@@ -575,6 +575,7 @@ class ArtifactOutput(StrEnum):
     pcrs = enum.auto()
     roothash = enum.auto()
     os_release = enum.auto()
+    appstream_metainfo = enum.auto()
 
     @staticmethod
     def compat_no() -> list["ArtifactOutput"]:
@@ -1986,6 +1987,13 @@ class Config:
     machine: Optional[str]
     forward_journal: Optional[Path]
 
+    appstream_id: Optional[str]
+    appstream_name: Optional[str]
+    appstream_summary: Optional[str]
+    appstream_description: Optional[str]
+    appstream_url: Optional[str]
+    appstream_icon: Optional[str]
+
     vmm: Vmm
     console: ConsoleMode
     cpus: int
@@ -2132,6 +2140,10 @@ def output_split_roothash(self) -> str:
     def output_split_os_release(self) -> str:
         return f"{self.output}.osrelease"
 
+    @property
+    def output_split_appstream_metainfo(self) -> str:
+        return f"{self.output}.metainfo.xml"
+
     @property
     def output_nspawn_settings(self) -> str:
         return f"{self.output}.nspawn"
@@ -2173,6 +2185,7 @@ def outputs(self) -> list[str]:
             self.output_split_pcrs,
             self.output_split_roothash,
             self.output_split_os_release,
+            self.output_split_appstream_metainfo,
             self.output_nspawn_settings,
             self.output_checksum,
             self.output_signature,
@@ -3977,6 +3990,42 @@ def parse_ini(path: Path, only_sections: Collection[str] = ()) -> Iterator[tuple
         default=ConfigFeature.auto,
         help="Run systemd-storagetm as part of the serve verb",
     ),
+    ConfigSetting(
+        dest="appstream_id",
+        section="Content",
+        parse=config_parse_string,
+        help="'id' field for Appstream metainfo file",
+    ),
+    ConfigSetting(
+        dest="appstream_name",
+        section="Content",
+        parse=config_parse_string,
+        help="'name' field for Appstream metainfo file",
+    ),
+    ConfigSetting(
+        dest="appstream_summary",
+        section="Content",
+        parse=config_parse_string,
+        help="'summary' field for Appstream metainfo file",
+    ),
+    ConfigSetting(
+        dest="appstream_description",
+        section="Content",
+        parse=config_parse_string,
+        help="'description' field for Appstream metainfo file",
+    ),
+    ConfigSetting(
+        dest="appstream_url",
+        section="Content",
+        parse=config_parse_string,
+        help="'url' homepage field for Appstream metainfo file",
+    ),
+    ConfigSetting(
+        dest="appstream_icon",
+        section="Content",
+        parse=config_parse_string,
+        help="'icon' URL field for Appstream metainfo file",
+    ),
 ]
 SETTINGS_LOOKUP_BY_NAME = {name: s for s in SETTINGS for name in [s.name, *s.compat_names]}
 SETTINGS_LOOKUP_BY_DEST = {s.dest: s for s in SETTINGS}
@@ -5033,6 +5082,12 @@ def summary(config: Config) -> str:
                         Make Initrd: {yes_no(config.make_initrd)}
                                 SSH: {yes_no(config.ssh)}
                     SELinux Relabel: {config.selinux_relabel}
+              Appstream Metainfo ID: {none_to_none(config.appstream_id)}
+            Appstream Metainfo Name: {none_to_none(config.appstream_name)}
+         Appstream Metainfo Summary: {none_to_none(config.appstream_summary)}
+     Appstream Metainfo Description: {none_to_none(config.appstream_description)}
+             Appstream Metainfo URL: {none_to_none(config.appstream_url)}
+                     Appstream Icon: {none_to_none(config.appstream_icon)}
 """
 
     if config.output_format.is_extension_or_portable_image() or config.output_format in (

mkosi/resources/man/mkosi.1.md

@@ -624,8 +624,8 @@ boolean argument: either `1`, `yes`, or `true` to enable, or `0`, `no`,
 `SplitArtifacts=`, `--split-artifacts=`
 :   The artifact types to split out of the final image. A comma-delimited
     list consisting of `uki`, `kernel`, `initrd`, `os-release`, `prcs`, `partitions`,
-    `roothash` and `tar`. When building a bootable image `kernel` and `initrd`
-    correspond to their artifact found in the image (or in the UKI),
+    `appstream-metainfo`, `roothash` and `tar`. When building a bootable image `kernel`
+    and `initrd` correspond to their artifact found in the image (or in the UKI),
     while `uki` copies out the entire UKI. If `pcrs` is specified, a JSON
     file containing the pre-calculated TPM2 digests is written out, according
     to the [UKI specification](https://uapi-group.org/specifications/specs/unified_kernel_image/#json-format-for-pcrsig),
@@ -1156,6 +1156,10 @@ boolean argument: either `1`, `yes`, or `true` to enable, or `0`, `no`,
    `mkosi.machine-id` exists in the local directory, the UUID to use is
    read from it. Otherwise, `uninitialized` will be written to `/etc/machine-id`.
 
+`AppstreamId=`, `--appstream-id=`, `AppstreamName=`, `--appstream-name=`, `AppstreamSummary=`, `--appstream-summary=`, `AppstreamDescription=`, `--appstream-description=`, `AppstreamUrl=`, `--appstream-url=`, `AppstreamIcon=`, `--appstream-icon=`
+:  Specifies content for the [appstream metainfo](https://www.freedesktop.org/software/appstream/docs/sect-Metadata-OS.html)
+   file. If not provided, the content will be derived from the os-release file.
+
 ### [Validation] Section
 
 `SecureBoot=`, `--secure-boot=`

mkosi/resources/mkosi-obs/mkosi.conf

@@ -14,7 +14,7 @@ LocalMirror=file:///.build.binaries/
 [Output]
 OutputDirectory=
 Checksum=yes
-SplitArtifacts=pcrs,roothash
+SplitArtifacts=pcrs,roothash,appstream-metainfo
 CompressOutput=zstd
 
 [Validation]

tests/test_json.py

@@ -98,6 +98,12 @@ def test_config() -> None:
     dump = textwrap.dedent(
         """\
         {
+            "AppstreamDescription": null,
+            "AppstreamIcon": null,
+            "AppstreamId": null,
+            "AppstreamName": null,
+            "AppstreamSummary": null,
+            "AppstreamUrl": null,
             "Architecture": "ia64",
             "Autologin": false,
             "BaseTrees": [
@@ -437,6 +443,12 @@ def test_config() -> None:
     )
 
     args = Config(
+        appstream_id=None,
+        appstream_name=None,
+        appstream_summary=None,
+        appstream_description=None,
+        appstream_url=None,
+        appstream_icon=None,
         architecture=Architecture.ia64,
         autologin=False,
         base_trees=[Path("/hello/world")],