Update Prometheus alerting rules after upgrading to 0.17.0

update-alerting-rules.py

#!/usr/bin/python

import re
import os
import sys

for root, dirs, files in os.walk('.'):
    if root.find('.git') != -1 or not files:
        continue

    for kv_file in files:
        annotation_regex = 'SUMMARY|DESCRIPTION|RUNBOOK'
        with open("{}/{}".format(root, kv_file), 'r') as fh:
            file_contents = []
            annotations = []
            for line in fh:
                if re.search(annotation_regex, line):
                    key, value = line.split(' ', 1)
                    key = key.lower()
                    line = "{} = {},\n".format(key, value.strip('\n'))
                    annotations.append("    {}".format(line))
                else:
                    line = line.replace('WITH', 'LABELS')
                    file_contents.append(line)

            if annotations:
                annotations.insert(0, 'ANNOTATIONS {\n')
                annotations.append('}\n')
                file_contents = file_contents + annotations
                try:
                    with open("{}/{}.new".format(root, kv_file), 'w') as new_fh:
                        new_fh.write(''.join(file_contents))
                    new_file = "{}/{}.new".format(root, kv_file)
                    original_file = "{}/{}".format(root, kv_file)
                    os.rename(new_file, original_file)
                except IOError as exc:
                    print >> sys.stderr, exc
                    sys.exit(1)

sys.exit(0)

Here is my try:

#!/usr/bin/python3

import re
import os
import sys

for root, dirs, files in os.walk('.'):
    if root.find('.git') != -1 or not files:
        continue

    for kv_file in files:
        if kv_file.endswith('.__prom_new__'):
            continue
        annotation_regex = re.compile(r'(\s*)(SUMMARY|DESCRIPTION|RUNBOOK)\s+(.+)\n$')
        in_name = "{}/{}".format(root, kv_file)
        out_name = "{}/{}.__prom_new__".format(root, kv_file)
        with open(in_name, 'r') as input:
            with open(out_name, 'w') as output:
                in_annotations = False
                indent = ''
                for line in input:
                    m = annotation_regex.match(line)
                    if m:
                        indent = m.group(1)
                        line = "  {}{} = {},\n".format(indent, m.group(2).lower(), m.group(3))
                        if not in_annotations:
                            output.write(indent + 'ANNOTATIONS {\n')
                            in_annotations = True
                        output.write(line)
                    else:
                        if in_annotations:
                            output.write(indent + '}\n')
                            in_annotations = False
                        line = line.replace('WITH', 'LABELS')
                        output.write(line)
                if in_annotations:
                    output.write(indent + '}\n')
                    in_annotations = False
        try:
            os.rename(out_name, in_name)
        except IOError as exc:
            print(exc, file=sys.stderr)
            sys.exit(1)
sys.exit(0)

I should point out that the above is still very rough with loads of potential for improvement.

For one, it requires that SUMMARY, DESCRIPTION, and RUNBOOK are all-caps. (But as a bonus of that, it will work with mixed files that contain both old and new syntax.)

@beorn7 thanks for your contribution.