95 lines
3.7 KiB
Markdown
95 lines
3.7 KiB
Markdown
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# Creating New Services
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1. Think about if the service can fit into one of the existing service models like: SaaS or WebApps, refere to the related documentation if that is the case.
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2. Create a new django app using `startapp` management command. For ilustrational purposes we will create a crontab services that will allow orchestra to manage user-based crontabs.
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```bash
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python3 manage.py startapp crontabs
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```
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3. Add the new *crontabs* app to the `INSTALLED_APPS` in your project's `settings.py`
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3. Create a `models.py` file with the data your service needs to keep in order to be managed by orchestra
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```python
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from django.db import models
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class CrontabSchedule(models.Model):
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account = models.ForeignKey('accounts.Account', verbose_name=_("account"))
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minute = models.CharField(_("minute"), max_length=64, default='*')
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hour = models.CharField(_("hour"), max_length=64, default='*')
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day_of_week = models.CharField(_("day of week"), max_length=64, default='*')
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day_of_month = models.CharField(_("day of month"), max_length=64, default='*')
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month_of_year = models.CharField(_("month of year"), max_length=64, default='*')
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class Meta:
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ordering = ('month_of_year', 'day_of_month', 'day_of_week', 'hour', 'minute')
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def __str__(self):
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rfield = lambda f: f and str(f).replace(' ', '') or '*'
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return "{0} {1} {2} {3} {4} (m/h/d/dM/MY)".format(
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rfield(self.minute), rfield(self.hour), rfield(self.day_of_week),
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rfield(self.day_of_month), rfield(self.month_of_year),
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)
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class Crontab(models.Model):
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account = models.ForeignKey('accounts.Account', verbose_name=_("account"))
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schedule = models.ForeignKey(CrontabSchedule, verbose_name=_("schedule"))
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description = models.CharField(_("description"), max_length=256, blank=True)
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command = models.TextField(_("content"))
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def __str__(self):
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return (self.description or self.command)[:32]
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```
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4. Create a `admin.py` to enable the admin interface, refere to [Django Admin documentation](https://docs.djangoproject.com/en/1.9/ref/contrib/admin/) for further customization.
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```python
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from django.contrib import admin
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from .models import CrontabSchedule, Crontab
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class CrontabScheduleAdmin(admin.ModelAdmin):
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pass
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class CrontabAdmin(admin.ModelAdmin):
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pass
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admin.site.register(CrontabSchedule, CrontabScheduleAdmin)
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admin.site.register(Crontab, CrontabAdmin)
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```
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5. Create a `api.py` to enable the REST API.
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6. Create a `backends.py` fiel with the needed backends for service orchestration and monitoring.
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```python
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import os
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import textwrap
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from django.utils.translation import ugettext_lazy as _
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from orchestra.contrib.orchestration import ServiceController, replace
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from orchestra.contrib.resources import ServiceMonitor
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class UNIXCronBackend(ServiceController):
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"""
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Basic UNIX cron support.
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"""
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verbose_name = _("UNIX cron")
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model = 'crons.CronTab'
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def prepare(self):
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super(UNIXCronBackend, self).prepare()
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self.accounts = set()
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def save(self, crontab):
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self.accounts.add(crontab.account)
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def delete(self, crontab):
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self.accounts.add(crontab.account)
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def commit(self):
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for account in self.accounts:
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crontab = None
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self.append("echo '' > %(crontab_path)s" % context)
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for crontab in account.crontabs.all():
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self.append("
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```
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7. Configure the routing
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