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The Configuration module |
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======================== |
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Kamaki CLI offers a configuration module named *config*. It features: |
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* The global dict *DEFAULTS* with all the configuration settings and default |
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values for running a kamaki CLI |
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* The class *Config* is a ConfigParser extension adjusted to offer |
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kamaki-specific functionalities (e.g., cloud management) |
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Instances of *kamaki.cli.config.Config* always store data at a local file, |
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the path of which, is usually given by user as a constructor parameter. If the |
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path of the configuration file is not specified explicitly, the value at |
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*kamaki.cli.config.CONFIG_PATH* is used instead. |
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Types of configuration options |
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------------------------------ |
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|
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There are at least two sections of configuration options i.e., the *global* |
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and the *cloud*. The *global* section is not special, but is used as the |
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default kamaki section by convention. The *Config* class is semantically |
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aware of the *cloud* types and handles them in a special way. Other |
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configuration types can also be created and managed in the same fashion as the |
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*global* ones. |
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|
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Kamaki preset global options, as they appear in the configuration file:: |
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|
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[global] |
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default_cloud= |
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colors=off |
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log_file=${HOME}/.kamaki.log |
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log_token=off |
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log_data=off |
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log_pid=off |
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max_threads=7 |
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history_file=${HOME}/.kamaki.history |
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user_cli=astakos |
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file_cli=pithos |
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server_cli=cyclades |
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flavor_cli=cyclades |
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network_cli=cyclades |
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ip_cli=cyclades |
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image_cli=image |
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config_cli=config |
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history_cli=history |
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|
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A cloud configuration is required to make kamaki run. The |
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`setup guide <../setup.html>`_ can help when setting one or more cloud |
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configurations. |
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|
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Suppose that a cloud service is available with *https://main.example.com* as |
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the authentication URL and *s0m3-t0k3n* as the user token. In this example, the |
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user has already configured kamaki to refer to the service by the name "main":: |
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|
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[cloud "main"] |
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url=https://main.example.com |
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token=s0m3-t0k3n |
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|
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Suppose that a different cloud service is also available with |
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*https://alternative.example.com* as the authentication URL and |
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*s0m3-0th3r-t0k3n* as the user token. Again, the user configured kamaki to |
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refer to this service as "alternative":: |
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|
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[cloud "alternative"] |
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url=https://alternative.example.com |
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token=s0m3-0th3r-t0k3n |
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If the user picks one of these clouds to be the default, the configuration file |
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will contain the following:: |
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|
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|
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[global] |
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default_cloud=main |
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... <omitted for clarity> |
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|
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[cloud "main"] |
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url=https://main.example.com |
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token=s0m3-t0k3n |
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|
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[cloud "alternative"] |
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url=https://alternative.example.com |
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token=s0m3-0th3r-t0k3n |
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|
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The Config class |
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---------------- |
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|
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The *kamaki.cli.config.Config* class (extends *RawConfigParser* which extends |
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`ConfigParser <http://docs.python.org/release/2.7/library/configparser.html>`_ |
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) offers the methods of the RawConfigParser class (e.g., *get*, *set*), as well |
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as some default settings for kamaki and some additional functionality for |
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managing cloud configurations. |
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.. code-block:: python |
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|
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# Initialize two Config instances. Only the first will contain kamaki |
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# default values |
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from kamaki.cli.config import Config |
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my_config = Config('/some/local/file.cnf') |
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config_without_default_values = Config(with_defaults=False) |
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.. note:: If no file path is given, the Config instance is initialized |
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.. note:: The *with_defaults* flag can be used to omit all default settings |
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from a kamaki Config instance e.g., in case of an external application that |
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does not need any of the kamaki globals. |
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|
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Here are the general purpose accessors offered by Config: |
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|
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* get(section, option): get the *value* of an *option* in the specified |
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*section* e.g., |
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.. code-block:: python__ |
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|
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# Example: get the default cloud (global.default_cloud option) |
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thread_limit = my_config.get('global', 'default_cloud') |
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* set(section, option, value): set the *value* for an *option* in the specified |
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*section* e.g., |
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.. code-block:: python |
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|
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# Example: set the default_cloud to "main" |
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my_config.set('global', 'default_cloud', 'main') |
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|
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* remove_option(section, option): remove an option from a section e.g., |
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.. code-block:: python |
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# Example: remove the default_cloud option - Config will resort to the |
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# default value for this option |
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my_config.remove_option('global', 'default_cloud') |
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Global options |
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-------------- |
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|
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The global options are used to specify the kamaki CLI and client behavior. A |
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detailed catalog can be found at the |
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`setup section <../setup.html#available-options>`_ . |
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In the Config context, the global options are just the options under the |
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*global* section. |
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Cloud options |
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------------- |
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|
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Cloud options are used to configure one or more cloud services. |
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The following methods are cloud-specific: |
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* get_cloud(cloud, option): Get the value of a cloud option e.g., |
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.. code-block:: python |
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# Get the Auth URL and token for the cloud "main" |
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auth_url = my_config.get_cloud('main', 'url') |
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auth_token = my_config.get_cloud('main', 'token') |
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|
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* set_cloud(cloud, option, value): Set the value of a cloud option e.g., |
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.. code-block:: python |
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# Example: set a new authenticate URL and token for cloud "main" |
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my_config.set_cloud('main', 'url', 'https://new.example.com') |
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my_config.set_cloud('main', 'token', 'n3e-t0k3n-f0r-m41n') |
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|
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* remove_from_cloud(cloud, option): Remove an option from the specified cloud |
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e.g., |
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.. code-block:: python |
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# Example: remove the token of the main cloud, for safety reasons |
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my_config.remove_from_cloud('main', 'url') |
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.. warning:: A get/set/remove_option with a "cloud" section is not valid. There |
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is a way of using the general purpose accessors for cloud configuration, |
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and it is presented bellow, but programmers are discouraged from using it:: |
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|
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my_config.get('cloud.main', 'url') |
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my_config.set('cloud.main', 'url', 'https://new.example.com') |
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my_config.remove_option('cloud.main', 'url') |
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Examples |
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-------- |
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Get the default cloud values from a configuration file |
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"""""""""""""""""""""""""""""""""""""""""""""""""""""" |
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.. code-block:: python |
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from kamaki.cli.config import Config |
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CONFIG_FILE_PATH = '/home/user/my.cnf' |
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cnf = Config(CONFIG_FILE_PATH) |
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try: |
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CLOUD_NAME = cnf.get('global', 'default_cloud') |
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AUTH_URL = cnf.get_cloud(CLOUD_NAME, 'url') |
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AUTH_TOKEN = cnf.get_cloud(CLOUD_NAME, 'token') |
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except KeyError: |
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print 'Error: no valid configuration of a default cloud' |
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Set a new cloud, name it "new_cloud" and set it as default |
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"""""""""""""""""""""""""""""""""""""""""""""""""""""""""" |
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.. code-block:: python |
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from kamaki.cli.config import Config |
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CONFIG_FILE_PATH = '/home/user/my.cnf' |
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CLOUD_NAME = 'new_cloud' |
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AUTH_URL = 'https://new.cloud.example.com' |
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AUTH_TOKEN = 'n3w-cl0ud-t0k3n' |
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cnf = Config(CONFIG_FILE_PATH) |
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cnf.set_cloud(CLOUD_NAME, 'url', AUTH_URL) |
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cnf.set_cloud(CLOUD_NAME, 'token', AUTH_TOKEN) |
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cnf.set('global', 'default_cloud', CLOUD_NAME) |
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# Push the changes to the configuration file |
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cnf.write() |
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List all clouds with their URLs, let the user pick one |
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"""""""""""""""""""""""""""""""""""""""""""""""""""""" |
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.. code-block:: python |
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from kamaki.cli.config import Config |
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cnf = Config() |
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for name, cloud in cnf.items('cloud'): |
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print 'Cloud', name, cloud['url'] |
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choice = raw_input('Type your cloud name, pls: ') |
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if choice in cnf.keys('cloud'): |
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cnf.set('global', 'default_cloud', choice) |
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else: |
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print 'No such cloud configured' |