oops_dictconfig 0.0.6

Create an oops Config from a definition encoded as a dict

python-oops-dictconfig
======================

Create an `oops.Config` object from a definition encoded as a dictionary.

Dependencies
------------

* python-oops (http://pypi.python.org/pypi/oops)

Also the following dependencies are required depending on the configs
you will use:

* python-oops-datedir-repo (http://pypi.python.org/pypi/oops_datedir_repo)
* python-oops-amqp (http://pypi.python.org/pypi/oops_datedir_repo)

For testing all of the above are needed, along with:

* python-testtools

Use
---

To use run::

from oops_dictconfig import config_from_dict

oops_config = config_from_dict(dict_config)

where `dict_config` is a `dict` describing the `oops.Config` that is
wanted.

The empty dict is valid, and will get you an `oops.Config` with
no publishers, however, you will usually want at least one publisher.

To do that have a `publishers` key in `dict_config` whose value is a list
of dicts. Each of those dicts will add a publisher to the `oops.Config`.

There is one mandatory key for all publisher types:

* type: the type of publisher, currently `"datedir"` and `"amqp"` are
supported.

All publishers support the following (deprecated) optional key. Instead of
using this, you should see the section on fallback publishers:

* new_only: if this is `True` then the publisher will be wrapped in
`oops.publish_only_new`, meaning that the oops will only
be sent to this publisher if no previous publisher in the
chain published it.

Each publisher type also has further options detailed below.

datedir
```````

There is one further mandatory key for the datedir publisher:

* error_dir: the path on filesystem where the oops should be written.
It doesn't need to already exist.

The following optional keys are also supported:

* inherit_id: If True, use the oops ID (if present) supplied in
the report, rather than always assigning a new one.
* stash_path: If True, the filename that the OOPS was written to
is stored in the OOPS report under the key 'datedir_repo_filepath'.
It is not stored in the OOPS written to disk, only the in-memory
model.

amqp
````

There are several other mandatory keys for the amqp publisher:

* host: the hostname of the AMQP broker to connect to. If a port
is needed then specify it after the hostname, separated by
a colon. Examples: `example.com`, `1.2.3.4:5022`.

* user: the username to use when connecting to the AMQP broker.

* password: the password to use when connecting to the AMQP broker.

* vhost: the vhost to send messages on the AMQP broker.

* exchange_name: The name of the exchange to publish to.

* routing_key: The routing key for messages.

There is one other optional key for the amqp publisher:

* inherit_id If True any 'True' 'id' in an OOPS report is
preserved. Handy if an id that has already been shown
to a user is being published (but uniqueness cannot be
guaranteed).

Fallback publishers
-------------------

Sometimes it is desirable to have a chain of publishers, where the next in
the chain is used if the current attempt reported failure. For example, you
can have an amqp publisher with a datedir fallback, so that if the amqp
broker is not reachable the oops are saved to a datedir, where they can
be forwarded later.

To do this create a publisher definition with a 'fallback_chain' key,
whose value is a list of publishers to chain, e.g.

{
'fallback_chain': [
{'type': 'amqp',
...
},
{'type': 'datedir',
...
}
]
}

Note that these chains can't be nested, so 'fallback_chain' can only appear
at the top level of the publishers list.

Examples
--------

The following would create a DateDirRepo as the only publisher::

{
'publishers': [
{
'type': 'datedir',
'error_dir': '/var/log/oopses/',
},
],
}

The following is a simple config for an AMQP publisher::

{
'publishers': [
{
'type': 'amqp',
'host': 'amqp.example.com:5302',
'user': 'oopsuser',
'password': 'oopspassword',
'vhost': 'oopses',
'exchange_name': 'oopses',
'routing_key': 'oopses',
},
],
}

The following is an example that publishes to AMQP with a fallback
to DateDirRepo if AMQP is not availble::

{
'publishers': [
{
'fallback_chain': [
{
'type': 'amqp',
'host': 'amqp.example.com:5302',
'user': 'oopsuser',
'password': 'oopspassword',
'vhost': 'oopses',
'exchange_name': 'oopses',
'routing_key': 'oopses',
},
{
'type': 'datedir',
'error_dir': '/var/log/oopses/',
},
],
},
],
}


Template
--------

You can set the template for oopses by adding a 'template' key to
the dict. This should itself be a dict mapping keys to default values.
The template will then be used by the config when creating oopses.

The most common use of this is to set the publisher for oopses
coming from that config::

{
'template': {
'publisher': 'myapp',
},
}


configglue
----------

If you are using configglue to manage your configuration an Option
subclass is supplied that can be used in your schema as appropriate::

from configglue import schema
from oops_dictconfig.configglue import OopsOption

class MySchema(schema.Schema):

oopses = OopsOption()


Once that is defined you can produce the config described above
using your configglue config file::

oopses = oopses_config

[oopses_config]
publishers = fallback_chain

[fallback_chain]
fallback_chain = amqp_publisher
datedir_publisher

[amqp_publisher]
type = amqp
host = amqp.example.com:6832
user = oopsuser
password = oopspassword
vhost = oopses
exchange_name = oopses
routing_key = oopses

[datedir_publisher]
type = datedir
error_dir = /var/log/oopses


Running Tests
-------------

Install `testrepository` and `python-subunit` and run::

testr init
testr run

or run::

python -m testtools.run oops_dictconfig.tests.test_suite


..

Copyright (c) 2012, Canonical Ltd

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, version 3 only.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
GNU Lesser General Public License version 3 (see the file LICENSE).