django-spanner on healthchecks.io

This example shows how to use django-spanner for Cloud Spanner as a backend database for https://healthchecks.io

Table of contents

• Install healthchecks

• Install django-spanner in the virtual-env

• Ensure you have a Cloud Spanner database already created

• Set credentials and project environment variables

• Update local_settings.py

• Run the server

• Apply the migrations

• Go view the results on Cloud Spanner UI

• Run the application

• References

Install healthchecks

Please follow the instructions to install healthchecks.io on Github. You’ll need to active the virtual-env as their install instructions request.

Install django-spanner in the virtual-env

Go to the directory in which you installed healthchecks and ensure your virtual-env is on. The prompt should look something like this:

(hc-venv) $

Install django-google-spanner from PyPI:

(h-venv) $ pip install django-google-spanner

Ensure you have a Cloud Spanner database already created

If you haven’t already, please follow the steps to install Cloud Spanner, or visit this codelab

Set credentials and project environment variables

You’ll need to download a service account JSON keyfile and point to it using an environment variable:

export GOOGLE_APPLICATION_CREDENTIALS=/path/to/keyfile.json
export GOOGLE_CLOUD_PROJECT=gcloud_project

Update local_settings.py

After we have a Cloud Spanner database created, we’ll need a few variables:

• ProjectID

• Instance name

• Database name aka DisplayName

NOTE: Healthchecks’s local_settings.py overrides the default settings mentioned in settings.py.

There are two ways to edit settings file:

1. You can edit the file hc/settings.py to:

   a) Add django_spanner as the first entry to INSTALLED_APPS:

   INSTALLED_APPS = [
       'django_spanner',  # Must be listed first.
       ...
   ]
   

   b) Edit DATABASES into the following:

   DATABASES = {
       'default': {
           'ENGINE': 'django_spanner',
           'PROJECT': PROJECT_ID,
           'INSTANCE': SPANNER_INSTANCE,
           'NAME': SPANNER_DATABASE_NAME,
       }
   }
   

2. You can edit the file hc/local_settings.py to:

   a) The INSTALLED_APPS MUST be copied from hc/settings.py to hc/local_settings.py and add django_spanner as the first entry to INSTALLED_APPS:

   INSTALLED_APPS = [
       'django_spanner',  # Must be listed first.
       ...
   ]
   

   b) Add or Edit DATABASES into the following:

   DATABASES = {
       'default': {
           'ENGINE': 'django_spanner',
           'PROJECT': PROJECT_ID,
           'INSTANCE': SPANNER_INSTANCE,
           'NAME': SPANNER_DATABASE_NAME,
       }
   }
   

and for example here is a filled in database where:

• PROJECT_ID: spanner-appdev

• INSTANCE: instance

• NAME: healthchecks_db

which when filled out, will look like this

DATABASES = {
    'default': {
        'ENGINE': 'django_spanner',
        'PROJECT': 'spanner-appdev',
        'INSTANCE': 'instance',
        'NAME': 'healthchecks_db',
    }
}

Run the server

With those steps out of the way, and having successfully setup both healthchecks and properly installed django-spanner, we are now ready to get started

(hc-venv) $ python3 manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).

You have 120 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): accounts, admin, api, auth, contenttypes, payments, sessions.
Run 'python manage.py migrate' to apply them.

April 06, 2020 - 01:45:23
Django version 3.0.3, using settings 'hc.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C

Apply the migrations

Please run:

(hc-venv) $ python3 manage.py migrate
Operations to perform:
  Apply all migrations: accounts, admin, api, auth, contenttypes, payments, sessions
Running migrations:

and that’ll take a while running, but when done, it will look like the following

(hc-venv) $ python3 manage.py migrate
Operations to perform:
  Apply all migrations: accounts, admin, api, auth, contenttypes, payments, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying accounts.0001_initial... OK
  Applying accounts.0002_profile_ping_log_limit... OK
  Applying accounts.0003_profile_token... OK
  Applying accounts.0004_profile_api_key... OK
  Applying accounts.0005_auto_20160509_0801... OK
  Applying accounts.0006_profile_current_team... OK
  Applying accounts.0007_profile_check_limit... OK
  Applying accounts.0008_profile_bill_to... OK
  Applying accounts.0009_auto_20170714_1734... OK
  Applying accounts.0010_profile_team_limit... OK
  Applying accounts.0011_profile_sort... OK
  Applying accounts.0012_auto_20171014_1002... OK
  Applying accounts.0013_remove_profile_team_access_allowed... OK
  Applying accounts.0014_auto_20171227_1530... OK
  Applying accounts.0015_auto_20181029_1858... OK
  Applying accounts.0016_remove_profile_bill_to... OK
  Applying accounts.0017_auto_20190112_1426... OK
  Applying accounts.0018_auto_20190112_1426... OK
  Applying accounts.0019_project_badge_key... OK
  Applying accounts.0020_auto_20190112_1950... OK
  Applying accounts.0021_auto_20190112_2005... OK
  Applying accounts.0022_auto_20190114_0857... OK
  Applying accounts.0023_auto_20190117_1419... OK
  Applying accounts.0024_auto_20190119_1540... OK
  Applying accounts.0025_remove_member_team... OK
  Applying accounts.0026_auto_20190204_2042... OK
  Applying accounts.0027_profile_deletion_notice_date... OK
  Applying accounts.0028_auto_20191119_1346... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... OK
  Applying api.0001_initial... OK
  Applying api.0002_auto_20150616_0732... OK
  Applying api.0003_auto_20150616_1249... OK
  Applying api.0004_auto_20150616_1319... OK
  Applying api.0005_auto_20150630_2021... OK
  Applying api.0006_check_grace... OK
  Applying api.0007_ping... OK
  Applying api.0008_auto_20150801_1213... OK
  Applying api.0009_auto_20150801_1250... OK
  Applying api.0010_channel... OK
  Applying api.0011_notification... OK
  Applying api.0012_auto_20150930_1922... OK
  Applying api.0013_auto_20151001_2029... OK
  Applying api.0014_auto_20151019_2039... OK
  Applying api.0015_auto_20151022_1008... OK
  Applying api.0016_auto_20151030_1107... OK
  Applying api.0017_auto_20151117_1032... OK
  Applying api.0018_remove_ping_body... OK
  Applying api.0019_check_tags... OK
  Applying api.0020_check_n_pings... OK
  Applying api.0021_ping_n... OK
  Applying api.0022_auto_20160130_2042... OK
  Applying api.0023_auto_20160131_1919... OK
  Applying api.0024_auto_20160203_2227... OK
  Applying api.0025_auto_20160216_1214... OK
  Applying api.0026_auto_20160415_1824... OK
  Applying api.0027_auto_20161213_1059... OK
  Applying api.0028_auto_20170305_1907... OK
  Applying api.0029_auto_20170507_1251... OK
  Applying api.0030_check_last_ping_body... OK
  Applying api.0031_auto_20170509_1320... OK
  Applying api.0032_auto_20170608_1158... OK
  Applying api.0033_auto_20170714_1715... OK
  Applying api.0034_auto_20171227_1530... OK
  Applying api.0035_auto_20171229_2008... OK
  Applying api.0036_auto_20180116_2243... OK
  Applying api.0037_auto_20180127_1215... OK
  Applying api.0038_auto_20180318_1306... OK
  Applying api.0039_remove_check_last_ping_body... OK
  Applying api.0040_auto_20180517_1336... OK
  Applying api.0041_check_desc... OK
  Applying api.0042_auto_20181029_1522... OK
  Applying api.0043_channel_name... OK
  Applying api.0044_auto_20181120_2004... OK
  Applying api.0045_flip... OK
  Applying api.0046_auto_20181218_1245... OK
  Applying api.0047_auto_20181225_2315... OK
  Applying api.0048_auto_20190102_0737... OK
  Applying api.0049_auto_20190102_0743... OK
  Applying api.0050_ping_kind... OK
  Applying api.0051_auto_20190104_0908... OK
  Applying api.0052_auto_20190104_1122... OK
  Applying api.0053_check_subject... OK
  Applying api.0054_auto_20190112_1427... OK
  Applying api.0055_auto_20190112_1427... OK
  Applying api.0056_auto_20190114_0857... OK
  Applying api.0057_auto_20190118_1319... OK
  Applying api.0058_auto_20190312_1716... OK
  Applying api.0059_auto_20190314_1744... OK
  Applying api.0060_tokenbucket... OK
  Applying api.0061_webhook_values... OK
  Applying api.0062_auto_20190720_1350... OK
  Applying api.0063_auto_20190903_0901... OK
  Applying api.0064_auto_20191119_1346... OK
  Applying api.0065_auto_20191127_1240... OK
  Applying api.0066_channel_last_error... OK
  Applying api.0067_last_error_values... OK
  Applying api.0068_auto_20200117_1023... OK
  Applying api.0069_auto_20200117_1227... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying auth.0009_alter_user_last_name_max_length... OK
  Applying auth.0010_alter_group_name_max_length... OK
  Applying auth.0011_update_proxy_permissions... OK
  Applying payments.0001_initial... OK
  Applying payments.0002_subscription_plan_id... OK
  Applying payments.0003_subscription_address_id... OK
  Applying payments.0004_subscription_send_invoices... OK
  Applying payments.0005_subscription_plan_name... OK
  Applying payments.0006_subscription_invoice_email... OK
  Applying sessions.0001_initial... OK

Go view the results on Cloud Spanner UI

To double check that the respective tables and migrations were performed, please go visit the page with your database on Cloud Spanner’s UI. For example it should look like this

Run the application

And now you should be able to run the application and then visit the link to it by

(hc-venv) $ python3 manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
April 06, 2020 - 20:49:25
Django version 2.2.1, using settings 'hc.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
[06/Apr/2020 20:49:35] "GET / HTTP/1.1" 200 29334
[06/Apr/2020 20:49:35] "GET /static/img/logo-full%402x.png HTTP/1.1" 200 8395
[06/Apr/2020 20:49:35] "GET /static/img/cron%402x.png HTTP/1.1" 200 31324
[06/Apr/2020 20:49:35] "GET /static/img/my_checks%402x.png HTTP/1.1" 200 29642
[06/Apr/2020 20:49:35] "GET /static/img/period_grace%402x.png HTTP/1.1" 200 23388
[06/Apr/2020 20:49:35] "GET /static/img/badges%402x.png HTTP/1.1" 200 28904
[06/Apr/2020 20:49:35] "GET /static/img/check_details%402x.png HTTP/1.1" 200 50342
[06/Apr/2020 20:49:35] "GET /static/img/favicon.ico HTTP/1.1" 200 5430
[06/Apr/2020 20:49:47] "POST /accounts/signup/ HTTP/1.1" 200 81
[06/Apr/2020 20:50:02] "POST /accounts/signup/ HTTP/1.1" 200 73

References

Resource|URL —|— Healthchecks app|https://healthchecks.io/ Healthchecks source code|https://github.com/healthchecks/healthchecks/ Cloud Spanner homepage|https://cloud.google.com/spanner/ django-spanner project’s source code|https://github.com/googleapis/python-spanner-django/