1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213
|
.. _developer:
Developer Guide
===============
.. module:: pypuppetdb
This part of the documentation covers all the interfaces of PyPuppetDB.
It will cover how the API is set up and how to configure which version of
the API to use.
Lazy objects
------------
.. note::
Reading in the response from PuppetDB is currently greedy, it will read in
the complete response no matter the size. This will change once streaming
and pagination support are added to PuppetDB's endpoints.
In order for pypuppetdb to be able to deal with big datasets those functions
that are expected to return more than a single item are implemented as
generators.
This is usually the case for functions with a plural name like
:func:`~pypuppetdb.api.QueryAPI.nodes` or :func:`~pypuppetdb.api.QueryAPI.facts`.
Because of this we'll only query PuppetDB once you start iterating over the
generator object. Until that time not a single request is fired at PuppetDB.
Most singular functions are implemented by calling their plural counterpart
and then iterating over the generator, immediately exhausting the generator
and returning a single/the first object.
API and BaseAPI classes
-----------------------
The starting point for the library is the :func:`connect` method used to set up a
connection with PuppetDB.
.. autofunction:: connect
This method returns the ``API`` class instance.
That class is built using mixins from the endpoint-specific classes, such as
``PqlAPI`` (see the next section for more info about them).
All the endpoint-specific classes inherit from the abstract ``BaseAPI`` class
which contains the logic shared by all the endpoints, such as:
* connecting to the PuppetDB (in the constructor),
* disconnecting from the PuppetDB (``disconnect()``),
* ``_query()`` and ``_make_request()`` that prepare and make HTTP(S) requests
to PuppetDB,
Endpoint classes
----------------
The supported PuppetDB endpoint types are implemented in classes with
corresponding names:
* pdb/query/v4 - ``PqlAPI``
* pdb/query/v4/* - ``QueryAPI``
* pdb/cmd/v1 - ``CommandAPI``
* status/v1/** - ``StatusAPI``
* pdb/meta/v1* - ``MetadataAPI``
* metrics/* - ``MetricsAPI``
PqlAPI
^^^^^^
.. autoclass:: pypuppetdb.api.PqlAPI
:members:
:private-members:
QueryAPI
^^^^^^^^
.. autoclass:: pypuppetdb.api.QueryAPI
:members:
:private-members:
CommandAPI
^^^^^^^^^^
.. autoclass:: pypuppetdb.api.CommandAPI
:members:
:private-members:
StatusAPI
^^^^^^^^^
.. autoclass:: pypuppetdb.api.StatusAPI
:members:
:private-members:
MetadataAPI
^^^^^^^^^^^
.. autoclass:: pypuppetdb.api.MetadataAPI
:members:
:private-members:
MetricsAPI
^^^^^^^^^^
.. autoclass:: pypuppetdb.api.MetricsAPI
:members:
:private-members:
Types
-----
In order to facilitate working with the API most methods like
:meth:`~pypuppetdb.api.QueryAPI.nodes` don't return the decoded
JSON response but return an object representation of the querried
endpoints data.
.. autoclass:: pypuppetdb.types.Node
:members:
.. autoclass:: pypuppetdb.types.Fact
.. autoclass:: pypuppetdb.types.Resource
.. autoclass:: pypuppetdb.types.Event
.. autoclass:: pypuppetdb.types.Report
:members:
.. autoclass:: pypuppetdb.types.Catalog
:members:
.. autoclass:: pypuppetdb.types.Edge
.. autoclass:: pypuppetdb.types.Inventory
Errors
------
Unfortunately things can go haywire. PuppetDB might not be reachable
or complain about our query, requests might have to wait too long to
receive a response or the body is just too big to handle.
In that case, we'll throw an exception at you.
.. autoexception:: pypuppetdb.errors.APIError
.. autoexception:: pypuppetdb.errors.ImproperlyConfiguredError
:show-inheritance:
.. autoexception:: pypuppetdb.errors.DoesNotComputeError
:show-inheritance:
.. autoexception:: pypuppetdb.errors.EmptyResponseError
:show-inheritance:
Query Builder
-------------
With the increasing complexities of some queries it can be very difficult
to maintain query strings as string objects. The 0.3.0 release introduces
a new feature called the Query Builder which removes the need of string
object concatenation into an Object-Oriented fashion.
In order to create the following query:
``'["and", ["=", "facts_environment", "production"], ["=", "catalog_environment", "production"]]'``
Users can use the following code block to create the same thing:
.. code-block:: python
>>> from pypuppetdb.QueryBuilder import *
>>> op = AndOperator()
>>> op.add(EqualOperator("facts_environment", "production"))
>>> op.add(EqualOperator("catalog_environment", "production"))
The ``op`` object can then be directly input to the query parameter of any
PuppetDB call.
.. code-block:: python
>>> pypuppetdb.nodes(query=op)
.. autoclass:: pypuppetdb.QueryBuilder.BinaryOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.EqualsOperator
.. autoclass:: pypuppetdb.QueryBuilder.GreaterOperator
.. autoclass:: pypuppetdb.QueryBuilder.LessOperator
.. autoclass:: pypuppetdb.QueryBuilder.GreaterEqualOperator
.. autoclass:: pypuppetdb.QueryBuilder.LessEqualOperator
.. autoclass:: pypuppetdb.QueryBuilder.RegexOperator
.. autoclass:: pypuppetdb.QueryBuilder.RegexArrayOperator
.. autoclass:: pypuppetdb.QueryBuilder.NullOperator
.. autoclass:: pypuppetdb.QueryBuilder.BooleanOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.AndOperator
.. autoclass:: pypuppetdb.QueryBuilder.OrOperator
.. autoclass:: pypuppetdb.QueryBuilder.NotOperator
.. autoclass:: pypuppetdb.QueryBuilder.ExtractOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.FunctionOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.SubqueryOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.InOperator
:members:
.. autoclass:: pypuppetdb.QueryBuilder.FromOperator
:members:
Utilities
---------
A few functions that are used across this library have been put
into their own :mod:`utils` module.
.. autoclass:: pypuppetdb.utils.UTC
.. autofunction:: pypuppetdb.utils.json_to_datetime
|