pxrecipe: Add the osrelease step that writes IMAGE_ID (recipe name) and IMAGE_VERSION (build tag) to /etc/os-release.

docs/docs/administration/images.md

@@ -24,6 +24,7 @@ The following parameters can be used to define a recipe:
 | package   | A string or list of strings of package names to install |
 | file      | Copy a file from the management node into the image. A string specifies a common source and destination. A mapping with `src` and `dst` can specify different paths |
 | command   | Run a command inside the image                          |
+| osrelease | Write `IMAGE_ID` (recipe name) and `IMAGE_VERSION` (build tag) to `/etc/os-release`. Accepts a boolean to enable `IMAGE_ID` and `IMAGE_VERSION`, or a dictionary of additional os-release fields. `IMAGE_ID` and `IMAGE_VERSION` is always added. |
 
 
 ### Artifact Types
@@ -57,6 +58,7 @@ steps:
       src: /root/hosts.mycluster
       dst: /etc/hosts
   - command: systemd-firstboot --timezone=America/New_York --locale=en_US.UTF-8 --locale-messages=en_US.UTF-8
+  - osrelease: true
 
 artifacts:
   - squashfs:

lib/phoenix/recipe.py

@@ -148,6 +148,8 @@ def load_recipe(self, name):
                             self.steps.append(StepPackage(step['package']))
                         elif steptype == 'file':
                             self.steps.append(StepFile(step['file']))
+                        elif steptype == 'osrelease':
+                            self.steps.append(StepOsRelease(step['osrelease']))
                         else:
                             self.steps.append(step)
             elif key == "artifacts":
@@ -443,6 +445,49 @@ def run(self, recipe):
             logging.error("Could not copy file  %s to %s", self.src, self.dst)
             raise RuntimeError
 
+class StepOsRelease(Step):
+    name = 'OsRelease'
+
+    def __init__(self, params):
+        # Optional mapping of additional os-release fields to set. IMAGE_ID
+        # and IMAGE_VERSION are always set from the recipe name and tag.
+        self.extra = dict()
+        if type(params) is dict:
+            self.extra = dict(params)
+
+    def __str__(self):
+        result = "IMAGE_ID=<name> IMAGE_VERSION=<tag>"
+        if self.extra:
+            result += " " + " ".join("%s=%s" % (k, v) for k, v in self.extra.items())
+        return result
+
+    def run(self, recipe):
+        osrelease = Path(recipe.root) / 'etc' / 'os-release'
+        fields = dict(self.extra)
+        fields['IMAGE_ID'] = recipe.name
+        fields['IMAGE_VERSION'] = recipe.tag
+        logging.info("Setting %s in %s",
+                     " ".join("%s=%s" % (k, v) for k, v in fields.items()),
+                     osrelease)
+
+        lines = []
+        if osrelease.is_file():
+            lines = osrelease.read_text().splitlines()
+
+        # Drop any pre-existing lines for the fields we are about to set
+        lines = [l for l in lines
+                 if not any(l.startswith("%s=" % key) for key in fields)]
+
+        for key, value in fields.items():
+            lines.append('%s="%s"' % (key, value))
+
+        try:
+            osrelease.parent.mkdir(parents=True, exist_ok=True)
+            osrelease.write_text('\n'.join(lines) + '\n')
+        except OSError as e:
+            logging.error("Could not write %s: %s", osrelease, e)
+            raise RuntimeError
+
 class Artifact(object):
     pass