[sonic-installer] Create Envvars File for Incoming Image (#1011)

Create environment files for SONiC immutable attribute. The file
will reside in the incoming image dir under sonic-config dir.
Incoming image will then move the file to /etc/sonic. The file
will be used to avoid calls into cfggen for those attributes.

signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>

setup.py

@@ -112,6 +112,7 @@
     ],
     data_files=[
         ('/etc/bash_completion.d', glob.glob('data/etc/bash_completion.d/*')),
+        ('/usr/share/sonic/templates', ['sonic_installer/templates/sonic-environment.j2']),
     ],
     entry_points={
         'console_scripts': [

sonic_installer/common.py

@@ -8,6 +8,8 @@
 
 import click
 
+from .exception import SonicRuntimeException
+
 HOST_PATH = '/host'
 IMAGE_PREFIX = 'SONiC-OS-'
 IMAGE_DIR_PREFIX = 'image-'
@@ -23,3 +25,15 @@ def run_command(command):
 
     if proc.returncode != 0:
         sys.exit(proc.returncode)
+
+# Run bash command and return output, raise if it fails
+def run_command_or_raise(argv):
+    click.echo(click.style("Command: ", fg='cyan') + click.style(' '.join(argv), fg='green'))
+
+    proc = subprocess.Popen(argv, stdout=subprocess.PIPE)
+    out, _ = proc.communicate()
+
+    if proc.returncode != 0:
+        raise SonicRuntimeException("Failed to run command '{0}'".format(argv))
+
+    return out.rstrip("\n")

sonic_installer/exception.py

@@ -0,0 +1,8 @@
+"""
+Module sonic_installer exceptions
+"""
+
+class SonicRuntimeException(Exception):
+    """SONiC Runtime Excpetion class used to report SONiC related errors
+    """
+    pass

sonic_installer/main.py

@@ -16,7 +16,8 @@
 from swsssdk import SonicV2Connector
 
 from .bootloader import get_bootloader
-from .common import run_command
+from .common import run_command, run_command_or_raise
+from .exception import SonicRuntimeException
 
 
 # Global Config object
@@ -208,6 +209,54 @@ def print_deprecation_warning(deprecated_cmd_or_subcmd, new_cmd_or_subcmd):
                 fg="red", err=True)
     click.secho("Please use '{}' instead".format(new_cmd_or_subcmd), fg="red", err=True)
 
+def update_sonic_environment(click, binary_image_version):
+    """Prepare sonic environment variable using incoming image template file. If incoming image template does not exist
+       use current image template file.
+    """
+    def mount_next_image_fs(squashfs_path, mount_point):
+        run_command_or_raise(["mkdir", "-p", mount_point])
+        run_command_or_raise(["mount", "-t", "squashfs", squashfs_path, mount_point])
+
+    def umount_next_image_fs(mount_point):
+        run_command_or_raise(["umount", "-rf", mount_point])
+        run_command_or_raise(["rm", "-rf", mount_point])
+
+    SONIC_ENV_TEMPLATE_FILE = os.path.join("usr", "share", "sonic", "templates", "sonic-environment.j2")
+    SONIC_VERSION_YML_FILE = os.path.join("etc", "sonic", "sonic_version.yml")
+
+    sonic_version = re.sub("SONiC-OS-", '', binary_image_version)
+    new_image_dir = os.path.join('/', "host", "image-{0}".format(sonic_version))
+    new_image_squashfs_path = os.path.join(new_image_dir, "fs.squashfs")
+    new_image_mount = os.path.join('/', "tmp", "image-{0}-fs".format(sonic_version))
+    env_dir = os.path.join(new_image_dir, "sonic-config")
+    env_file = os.path.join(env_dir, "sonic-environment")
+
+    try:
+        mount_next_image_fs(new_image_squashfs_path, new_image_mount)
+
+        next_sonic_env_template_file = os.path.join(new_image_mount, SONIC_ENV_TEMPLATE_FILE)
+        next_sonic_version_yml_file = os.path.join(new_image_mount, SONIC_VERSION_YML_FILE)
+
+        sonic_env = run_command_or_raise([
+                "sonic-cfggen",
+                "-d",
+                "-y",
+                next_sonic_version_yml_file,
+                "-t",
+                next_sonic_env_template_file,
+        ])
+        os.mkdir(env_dir, 0o755)
+        with open(env_file, "w+") as ef:
+            print >>ef, sonic_env
+        os.chmod(env_file, 0o644)
+    except SonicRuntimeException as ex:
+        click.secho("Warning: SONiC environment variables are not supported for this image: {0}".format(str(ex)),
+                    fg="red", err=True)
+        if os.path.exists(env_file):
+            os.remove(env_file)
+            os.rmdir(env_dir)
+    finally:
+        umount_next_image_fs(new_image_mount)
 
 # Main entrypoint
 @click.group(cls=AliasedGroup)
@@ -274,6 +323,8 @@ def install(url, force, skip_migration=False):
         else:
             run_command('config-setup backup')
 
+        update_sonic_environment(click, binary_image_version)
+
     # Finally, sync filesystem
     run_command("sync;sync;sync")
     run_command("sleep 3")  # wait 3 seconds after sync

sonic_installer/templates/sonic-environment.j2

@@ -0,0 +1,5 @@
+SONIC_VERSION={{ build_version }}
+PLATFORM={{ DEVICE_METADATA.localhost.platform }}
+HWSKU={{ DEVICE_METADATA.localhost.hwsku }}
+DEVICE_TYPE={{ DEVICE_METADATA.localhost.type }}
+ASIC_TYPE={{ asic_type }}