Source code for promgen.templatetags.promgen

# Copyright (c) 2017 LINE Corporation
# These sources are released under the terms of the MIT license: see LICENSE

import collections
import difflib
import json
from datetime import datetime
from urllib.parse import urlencode

import yaml
from django import template
from django.urls import reverse
from django.utils.html import format_html
from django.utils.safestring import mark_safe
from django.utils.translation import gettext as _
from pytz import timezone

from promgen import util

register = template.Library()

EXCLUSION_MACRO = "<exclude>"




[docs]
@register.filter()
def klass(value):
    return value.__class__.__name__






[docs]
@register.filter()
def rule_dict(rule):
    return {
        "alert": rule.name,
        "expr": rulemacro(rule),
        "for": rule.duration,
        "labels": rule.labels,
        "annotations": rule.annotations,
    }






[docs]
@register.filter()
def rulemacro(rule, clause=None):
    """
    Macro rule expansion

    Assuming a list of rules with children and parents, expand our macro to exclude child rules

    Can optionally pass expression to render in the context of the passed rule

    .. code-block:: none

        foo{<exclude>} / bar{<exclude>} > 5 # Parent Rule
        foo{project="A", <exclude>} / bar{project="A", <exclude>} > 3 # Child Rule
        foo{project="B"} / bar{project="B"} > 4 # Child Rule

        foo{project~="A|B"} / bar{project~="A|B"} > 5
        foo{project="A", } / bar{project="A"} > 3
        foo{project="B"} / bar{project="B"} > 4
    """

    if not clause:
        clause = rule.clause

    labels = collections.defaultdict(list)
    for r in rule.overrides.all():
        labels[r.content_type.model].append(r.content_object.name)

    filters = {k: "|".join(labels[k]) for k in sorted(labels)}
    macro = ",".join(sorted(f'{k}!~"{v}"' for k, v in filters.items()))
    return clause.replace(EXCLUSION_MACRO, macro)






[docs]
@register.simple_tag
def diff_json(a, b):
    if isinstance(a, str):
        a = json.loads(a)
    if isinstance(b, str):
        b = json.loads(b)
    a = json.dumps(a, indent=4, sort_keys=True).splitlines(keepends=True)
    b = json.dumps(b, indent=4, sort_keys=True).splitlines(keepends=True)
    diff = "".join(difflib.unified_diff(a, b))
    if diff:
        return diff
    return "No Changes"






[docs]
@register.filter()
def pretty_json(data):
    if isinstance(data, str):
        data = json.loads(data)
    return json.dumps(data, indent=4, sort_keys=True)






[docs]
@register.filter()
def pretty_yaml(data):
    return yaml.safe_dump(data)






[docs]
@register.filter()
def strftime(timestamp, fmt):
    tz = util.setting("timezone", "UTC")
    if isinstance(timestamp, int) or isinstance(timestamp, float):
        return timezone(tz).localize(datetime.fromtimestamp(timestamp)).strftime(fmt)
    return timestamp










[docs]
@register.simple_tag(takes_context=True)
def qs_replace(context, k, v):
    """
    Query string handler for paginators

    Assuming we have a query string like ?page=1&search=foo, there are several cases
    in which we want to replace only the page key, while leaving the rest alone.
    This tag allows us to replace individual values (like the current page) while
    carrying over other values (like a search string)

    Example:
    {% qs_replace 'page' page_obj.next_page_number %}
    """
    dict_ = context["request"].GET.copy()
    if v:
        dict_[k] = v
    else:
        dict_.pop(k, None)
    return dict_.urlencode()






[docs]
@register.simple_tag
def urlqs(view, **kwargs):
    """
    Query string aware version of url template

    Instead of using {% url 'view' %}
    Use {% urlqs 'view' param=value %}

    This is useful for linking to pages that use filters.
    This only works for views that do not need additional parameters
    """
    return reverse(view) + "?" + urlencode(kwargs)