3. PDC Client¶
PDC Client is a shell CLI that make it easier to access data from PDC servers.
3.1. Installation¶
You can obtain the client from the same repository where PDC server is.
3.2. Configuration¶
The client can read server connection details from a configuration file. The
configuration file should be located in /etc/pdc/client_config.json or in
~/.config/pdc/client_config.json. If both files are present, the system one
is loaded first and the user configuration is applied on top of it (to add
other options or overwrite existing ones).
The configuration file should contain a JSON object, which maps server name to JSON object with details. The name is an arbitrary string used at client run time to identify which server you want to connect to.
The details of a single server must contain at least one key: host which
specifies the URL to the API root (e.g. http:://localhost:8000/rest_api/v1/
for local instance).
Other possible keys are:
token- If specified, this token will be used for authentication. The client will not try to obtain any token from the server.
insecure- If set to
true, server certificate will not be validated. develop- When set to
true, the client will not use any authentication at all, not requesting a token nor sending any token with the requests. This is only useful for working with servers which don’t require authentication.
3.2.1. Example system configuration¶
This config defines connection to development server running on localhost and a production server.
{
"local": {
"host": "http://localhost:8000/rest_api/v1/",
"develop": true,
"insecure": false
},
"prod": {
"host": "https://pdc.example.com/rest_api/v1/",
}
}
3.3. Usage¶
The client package contains two separate clients. Both contain extensive
built-in help. Just run the executable with -h or --help argument.
3.3.1. pdc_client¶
This is a very simple client. Essentially this is just a little more convenient
than using curl manually. Each invocation of this client obtains a token
and then performs a single request.
This client is not meant for direct usage, but just as a helper for integrating with PDC from languages where it might be easier than performing the network requests manually.
3.3.2. pdc¶
This is much more user friendly user interface. A single invocation can perform multiple requests depending on what subcommand you used.
3.4. Python API¶
When writing a client code interfacing with PDC server, you might find
PDCClient handy. It provides access to the configuration defined above and
automates obtaining authorization token.
To use this module, you will need to install its dependencies. These include
When working with paginated responses, there is a utility function to simplify that. From client code it is iterating single object. Behind the scenes it will download the first page, once all results from that page are exhausted, it will get another page until everything is processed.
3.5. Known Issues¶
3.5.1. Kerberos¶
Under enterprise network, Reverse DNS mismatches may cause problems authenticating with Kerberos.
If you can successfully run kinit but not authenticate yourself to PDC
servers, check /etc/krb5.conf and make sure that rdns is set to false
in libdefaults section.
[libdefaults]
rdns = false
3.6. For Developers¶
3.6.1. Instalation details¶
yum repository
If you have installed PDC Server by some yum repository, PDC Client is in the same repository that you used.
So to install PDC Client, just need to
$ sudo yum install pdc-client -y
build from source
If you have got the code and setup your development environment (see Setup development environment), then you could build from source and install the client and it’s dependency package python-pdc
$ git checkout `{release-tag}` $ make rpm $ sudo yum install dist/noarch/python-pdc*.noarch.rpm dist/noarch/pdc-client*.noarch.rpm