healthchecks/hc/api/transports.py

from django.conf import settings
from django.template.loader import render_to_string
from django.utils import timezone
import json
import requests
from six.moves.urllib.parse import quote

from hc.lib import emails


def tmpl(template_name, **ctx):
    template_path = "integrations/%s" % template_name
    return render_to_string(template_path, ctx).strip()


class Transport(object):
    def __init__(self, channel):
        self.channel = channel

    def notify(self, check):
        """ Send notification about current status of the check.

        This method returns None on success, and error message
        on error.

        """

        raise NotImplementedError()

    def test(self):
        """ Send test message.

        This method returns None on success, and error message
        on error.

        """

        raise NotImplementedError()

    def checks(self):
        return self.channel.user.check_set.order_by("created")


class Email(Transport):
    def notify(self, check):
        if not self.channel.email_verified:
            return "Email not verified"

        ctx = {
            "check": check,
            "checks": self.checks(),
            "now": timezone.now(),
            "unsub_link": self.channel.get_unsub_link()
        }
        emails.alert(self.channel.value, ctx)


class HttpTransport(Transport):

    def request(self, method, url, **kwargs):
        try:
            options = dict(kwargs)
            if "headers" not in options:
                options["headers"] = {}

            options["timeout"] = 5
            options["headers"]["User-Agent"] = "healthchecks.io"

            r = requests.request(method, url, **options)
            if r.status_code not in (200, 201, 204):
                return "Received status code %d" % r.status_code
        except requests.exceptions.Timeout:
            # Well, we tried
            return "Connection timed out"
        except requests.exceptions.ConnectionError:
            return "Connection failed"

    def get(self, url):
        return self.request("get", url)

    def post(self, url, **kwargs):
        return self.request("post", url, **kwargs)


class Webhook(HttpTransport):
    def prepare(self, template, check, urlencode=False):
        """ Replace variables with actual values.

        There should be no bad translations if users use $ symbol in
        check's name or tags, because $ gets urlencoded to %24

        """

        def safe(s):
            return quote(s) if urlencode else s

        result = template
        if "$CODE" in result:
            result = result.replace("$CODE", str(check.code))

        if "$STATUS" in result:
            result = result.replace("$STATUS", check.status)

        if "$NOW" in result:
            s = timezone.now().replace(microsecond=0).isoformat()
            result = result.replace("$NOW", safe(s))

        if "$NAME" in result:
            result = result.replace("$NAME", safe(check.name))

        if "$TAG" in result:
            for i, tag in enumerate(check.tags_list()):
                placeholder = "$TAG%d" % (i + 1)
                result = result.replace(placeholder, safe(tag))

        return result

    def notify(self, check):
        url = self.channel.value_down
        if check.status == "up":
            url = self.channel.value_up

        if not url:
            # If the URL is empty then we do nothing
            return "no-op"

        url = self.prepare(url, check, urlencode=True)
        if self.channel.post_data:
            payload = self.prepare(self.channel.post_data, check)
            return self.post(url, data=payload)
        else:
            return self.get(url)


class Slack(HttpTransport):
    def notify(self, check):
        text = tmpl("slack_message.json", check=check)
        payload = json.loads(text)
        return self.post(self.channel.slack_webhook_url, json=payload)


class HipChat(HttpTransport):
    def notify(self, check):
        text = tmpl("hipchat_message.html", check=check)
        payload = {
            "message": text,
            "color": "green" if check.status == "up" else "red",
        }
        return self.post(self.channel.value, json=payload)


class OpsGenie(HttpTransport):

    def notify(self, check):
        payload = {
            "apiKey": self.channel.value,
            "alias": str(check.code),
            "source": "healthchecks.io"
        }

        if check.status == "down":
            payload["tags"] = ",".join(check.tags_list())
            payload["message"] = tmpl("opsgenie_message.html", check=check)
            payload["note"] = tmpl("opsgenie_note.html", check=check)

        url = "https://api.opsgenie.com/v1/json/alert"
        if check.status == "up":
            url += "/close"

        return self.post(url, json=payload)


class PagerDuty(HttpTransport):
    URL = "https://events.pagerduty.com/generic/2010-04-15/create_event.json"

    def notify(self, check):
        description = tmpl("pd_description.html", check=check)
        payload = {
            "service_key": self.channel.value,
            "incident_key": str(check.code),
            "event_type": "trigger" if check.status == "down" else "resolve",
            "description": description,
            "client": "healthchecks.io",
            "client_url": settings.SITE_ROOT
        }

        return self.post(self.URL, json=payload)


class Pushbullet(HttpTransport):
    def notify(self, check):
        text = tmpl("pushbullet_message.html", check=check)
        url = "https://api.pushbullet.com/v2/pushes"
        headers = {
            "Access-Token": self.channel.value,
            "Conent-Type": "application/json"
        }
        payload = {
            "type": "note",
            "title": "healthchecks.io",
            "body": text
        }

        return self.post(url, json=payload, headers=headers)


class Pushover(HttpTransport):
    URL = "https://api.pushover.net/1/messages.json"

    def notify(self, check):
        others = self.checks().filter(status="down").exclude(code=check.code)
        ctx = {
            "check": check,
            "down_checks": others,
        }
        text = tmpl("pushover_message.html", **ctx)
        title = tmpl("pushover_title.html", **ctx)
        user_key, prio = self.channel.value.split("|")
        payload = {
            "token": settings.PUSHOVER_API_TOKEN,
            "user": user_key,
            "message": text,
            "title": title,
            "html": 1,
            "priority": int(prio),
        }

        # Emergency notification
        if prio == "2":
            payload["retry"] = settings.PUSHOVER_EMERGENCY_RETRY_DELAY
            payload["expire"] = settings.PUSHOVER_EMERGENCY_EXPIRATION

        return self.post(self.URL, data=payload)


class VictorOps(HttpTransport):
    def notify(self, check):
        description = tmpl("victorops_description.html", check=check)
        payload = {
            "entity_id": str(check.code),
            "message_type": "CRITICAL" if check.status == "down" else "RECOVERY",
            "entity_display_name": check.name_then_code(),
            "state_message": description,
            "monitoring_tool": "healthchecks.io",
        }

        return self.post(self.channel.value, json=payload)


class Discord(HttpTransport):
    def notify(self, check):
        text = tmpl("slack_message.json", check=check)
        payload = json.loads(text)
        url = self.channel.discord_webhook_url + "/slack"
        return self.post(url, json=payload)