stages/yum: only write known options to repo file

This is similar to the previous commit for the dnf stage.

Don't pass through arbitrary options. This means that pipeline repo
objects don't have the same options as yum repo files anymore:

1. Hard code repo name to repo id. The name has no influence on the
resulting image and should thus not appear in a pipeline.

2. Set gpgcheck=1 when gpgkey is given. It defaults to false, which
means that all sample and test pipelines didn't verify packages. It
would have failed anyway, because the container doesn't have the key
referenced in /etc. Change all gpgkeys to refer to the key id and import
them manually.

3. Don't allow lists for baseurl and gpgkey. We can add that if we need
it at some point.

Also be less verbose.

samples/base-from-yum.json

@@ -10,9 +10,8 @@
           "basearch": "x86_64",
           "repos": {
             "fedora": {
-              "name": "Fedora",
               "baseurl": "https://archives.fedoraproject.org/pub/archive/fedora/linux/releases/$releasever/Everything/$basearch/os/",
-              "gpgkey": "file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$releasever-$basearch"
+              "gpgkey": "860E 19B0 AFA8 00A1 7518 81A6 F55E 7430 F528 2EE4"
             }
           },
           "packages": [

samples/build-from-yum.json

@@ -8,9 +8,8 @@
         "basearch": "x86_64",
         "repos": {
           "fedora": {
-            "name": "Fedora",
             "baseurl": "https://archives.fedoraproject.org/pub/archive/fedora/linux/releases/$releasever/Everything/$basearch/os/",
-            "gpgkey": "file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$releasever-$basearch"
+            "gpgkey": "860E 19B0 AFA8 00A1 7518 81A6 F55E 7430 F528 2EE4"
           }
         },
         "packages": [

stages/org.osbuild.yum

@@ -5,6 +5,28 @@ import subprocess
 import sys
 
 
+def write_repofile(f, repoid, repo):
+    f.write(f"[{repoid}]\n")
+
+    def write_option(key, value):
+        f.write(f"{key}={value}\n")
+
+    # silence dnf warning about missing name
+    write_option("name", repoid)
+
+    for key in ("metalink", "mirrorlist", "baseurl"):
+        value = repo.get(key)
+        if value:
+            write_option(key, value)
+
+    if "gpgkey" in repo:
+        keyfile = f"/tmp/{repoid}.asc"
+        subprocess.run(["gpg2", "--recv-keys", repo["gpgkey"]], check=True)
+        subprocess.run(["gpg2", "--armor", "--output", keyfile, "--export", repo["gpgkey"]], check=True)
+        write_option("gpgcheck", 1)
+        write_option("gpgkey", f"file://{keyfile}")
+
+
 def main(tree, options):
     repos = options["repos"]
     packages = options["packages"]
@@ -14,20 +36,7 @@ def main(tree, options):
 
     with open("/tmp/yum.conf", "w") as conf:
         for repoid, repo in repos.items():
-            conf.write(f"[{repoid}]\n")
-            for key, value in repo.items():
-                if isinstance(value, str):
-                    s = value
-                elif isinstance(value, list):
-                    s = " ".join(value)
-                elif isinstance(value, bool):
-                    s = "1" if value else "0"
-                elif isinstance(value, int):
-                    s = str(value)
-                else:
-                    print(f"unkown type for `{key}`: {value} ({type(value)})")
-                    return 1
-                conf.write(f"{key}={s}\n")
+            write_repofile(conf, repoid, repo)
 
     script = f"""
         set -e
@@ -43,7 +52,7 @@ def main(tree, options):
         return err.returncode
 
     cmd = [
-        "yum", "-y", "-v",
+        "yum", "--assumeyes",
         f"--installroot={tree}",
         "--setopt=\"reposdir=\"",
         f"--releasever={releasever}",