django-timeseries 1.0.0

# TimeSeries

[](https://travis-ci.org/anthonyalmarza/timeseries)

`timeseries` is a set django application tools designed to facilitate the
collation and maintenance of timeseries data.

## Requirements

Django versions 1.8+ are supported for projects running on PostgreSQL.

## Installation

`pip install django-timeseries`

## Usage

```python
from datetime import timedelta
from django.db import models
from timeseries.utils import TimeSeriesModel, TimeSeriesManager


class Ad(models.Model):

objects = TimeSeriesManager()


class RawAdData(TimeSeriesModel):

TIMESERIES_INTERVAL = timedelta(days=1) # update daily N.B integers in seconds also work

NOT_AVAILABLE = -1

ad = models.ForeignKey(Ad, related_name='rawdata')

views = models.BigIntegerField(default=NOT_AVAILABLE)
clicks = models.BigIntegerField(default=NOT_AVAILABLE)


class MonthlyAdReport(TimeSeriesModel):

TIMESERIES_INTERVAL = timedelta(days=28)

ad = models.ForeignKey(Ad, related_name='monthlyreports')

avg_view_growth = models.FloatField()
avg_click_growth = models.FloatField()


def ad_data_collector(queryset):
"""
should return an iterable that yields dictionaries of data
needed to successfully create a RawAdData instance
"""
return ...


def report_data_collector(queryset):
"""
should return an iterable that yields dictionaries of data
needed to successfully create a MonthlyAdReport instance
"""
return ...


# in a shell
>>> Ad.objects.update_timeseries('rawdata', ad_data_collector)
# this return the results of a bulk_create call from the RawAdData manager
# for ads that hadn't been updated in the last day

>>> Ad.objects.update_timeseries('monthlyreports', report_data_collector)
# this return the results of a bulk_create call from the MonthlyAdReport
# manager for ads that hadn't had a report generated in the last 28 days

>>> ad = Ad.objects.prefetch_latest('rawdata', 'monthlyreports').first()
>>> print ad.latest_rawaddata, ad.latest_monthlyreports

```


## TimeSeries QuerySet Methods

`timeseries.utils.TimeSeriesQuerySet`

Adds 4 main methods to the Django QuerySet API that can be used to
update and maintain timeseries data. These methods include:

* prefetch_latest
* filter_outdated
* last_updated
* update_timeseries


### `update_timeseries`

Inputs: `related_name`, `collector`, optional `force`

Returns: list of instatiated related models.

Updates the queryset's related model table
(as given by related_name) using a provider "collector" callable.

"collector" must take a queryset of the referenced models as its
only argument. It must also return an iterable of dictionaries
that can be used to construct and save instances of the related
model.

N.B. Only instances that have outdated data will be updated unless
explicitly forced using the "force" keyword argument.


### `filter_outdated`

Inputs: `*related_names`

Returns: queryset

Returns a queryset that will yield the model instances that have
"outdated" data associated to reverse related model as given by
the specified related_name.

### `last_updated`

Inputs: `*related_names`

Returns: queryset

Annotates the created timestamp of the latest related instance as
given by the reverse relation's related_name.

Usage:

```python
ad = Ad.objects.last_updated('rawdata').first()
# assuming there's data related to ad
print ad.rawdata_last_updated
# this will print the timestamp of when the associated data was
# last updated
```

### `prefetch_latest`

Inputs: `*related_names`

Returns: queryset

Exposes the latest associated reverse relation.

Usage:

```python
ad = Ad.objects.prefetch_latest('rawdata', 'monthlyreports').first()
print ad.latest_rawaddata, ad.latest_monthlyreports
# this will print the reprs of the latest associated data
# instances
```


## Other Utilities

### `LatestQ`

`timeseries.utils`

Inputs: `related_name`, `**kwargs`

Returns: django.db.models.Q instance

Constructs a django.db.models.Q instance that allows queries to be
executed against the latest associated reverse relation.

N.B. this method is designed to be used in conjunction with
timeseries.utils.TimeSeriesQuerySet.last_updated.

Usage:

```python
Ad.objects.last_updated('rawdata').filter(
LatestQ('rawdata', views__gt=1000)
)
```