[build_debian] Include checksum of ASIC config files in SONiC filesystem (#3384)

[build_debian] Generate checksum of ASIC config files

* Adds script to generate checksums for ASIC config files
* Adds step to build_debian that copies ASIC config checksum into SONiC filesystem

Signed-off-by: Danny Allen daall@microsoft.com

build_debian.sh

@@ -463,6 +463,14 @@ build_number: ${BUILD_NUMBER:-0}
 built_by: $USER@$BUILD_HOSTNAME
 EOF
 
+## Copy ASIC config checksum
+python files/build_scripts/generate_asic_config_checksum.py
+if [[ ! -f './asic_config_checksum' ]]; then
+    echo 'asic_config_checksum not found'
+    exit 1
+fi
+sudo cp ./asic_config_checksum $FILESYSTEM_ROOT/etc/sonic/asic_config_checksum
+
 if [ -f sonic_debian_extension.sh ]; then
     ./sonic_debian_extension.sh $FILESYSTEM_ROOT $PLATFORM_DIR
 fi

files/build_scripts/generate_asic_config_checksum.py

@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+
+import syslog
+import os
+import hashlib
+
+SYSLOG_IDENTIFIER = 'asic_config_checksum'
+
+CHUNK_SIZE = 8192
+
+CONFIG_FILES = {
+    os.path.abspath('./src/sonic-swss/swssconfig/sample/'): ['netbouncer.json', '00-copp.config.json']
+}
+
+OUTPUT_FILE = os.path.abspath('./asic_config_checksum')
+
+def log_info(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_INFO, msg)
+    syslog.closelog()
+
+def log_error(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_ERR, msg)
+    syslog.closelog()
+
+def get_config_files(config_file_map):
+    '''
+    Generates a list of absolute paths to ASIC config files.
+    '''
+    config_files = []
+    for path, files in config_file_map.items():
+        for config_file in files:
+            config_files.append(os.path.join(path, config_file))
+    return config_files
+
+def generate_checksum(checksum_files):
+    '''
+    Generates a checksum for a given list of files. Returns None if an error
+    occurs while reading the files.
+    
+    NOTE: The checksum is performed in the order provided. This function does 
+    NOT do any re-ordering of the files before creating the checksum.
+    '''
+    checksum = hashlib.sha1()
+    for checksum_file in checksum_files:
+        try:
+            with open(checksum_file, 'r') as f:
+                for chunk in iter(lambda: f.read(CHUNK_SIZE), b""):
+                    checksum.update(chunk)
+        except IOError as e:
+            log_error('Error processing ASIC config file ' + checksum_file + ':' + e.strerror)
+            return None
+
+    return checksum.hexdigest()
+
+def main():
+    config_files = sorted(get_config_files(CONFIG_FILES))
+    checksum = generate_checksum(config_files)
+    if checksum == None:
+        exit(1)
+
+    with open(OUTPUT_FILE, 'w') as output:
+        output.write(checksum + '\n')
+
+if __name__ == '__main__':
+    main()