[rudder-dev] Relay API

[Nicolas Charles]

Le 18/11/2016 à 18:20, Benoit Peccatte a écrit :
> Le 18/11/2016 à 10:17, Nicolas Charles a écrit :
>> Hello Benoit,
>>
>> Thank you for the details, I simply have one question, inline
>>
>> Le 04/11/2016 à 17:38, Benoit Peccatte a écrit :
>>>
>>> Hello,
>>>
>>> One of Rudder 4.1 new features will be relay APIs. This is the first 
>>> attempt to describe it.
>>>
>>> There are currently 2 API entries we want to add: remote-run and 
>>> share-files.
>>> They will both be under /rudder/relay-api itself under 
>>> https://<server>:<port>/ like the current api is.
>>> /rudder is the common root for all rudder service
>>> /relay-api is different from existing api to avoid conflicts with 
>>> them when it will be installed on the server
>>>
>>>
>>> 1. Remote-run:
>>>
>>> The goal is to make a given relay call "rudder remote run" on one of 
>>> its attached node
>>> The API will be under /rudder/relay-api/remote-run
>>> GET remote-run/node/<node-uuid>
>>> GET remote-run/all
>>> GET remote-run/nodes
>>>
>>> Parameters:
>>> - output = keep / discard : to keep the output of the remote-run 
>>> call or discard its content
>>> - async = yes / no : yes to ignore the return code of the call and 
>>> return immediately, no to wait until the end of the call and get the 
>>> return code
>>> - classes = XXX : list of cfengine classes to set during the remote 
>>> call
>>> - nodes = uuid,... : list of uuid to call in the "/nodes" case
>>>
>>> Behavior:
>>> - Loop on all nodes
>>> - Find its hostname from its uuid in a matching file created by 
>>> promise generation on the server
>>> - The call is descending, so we don't care about host that do not exist
>>> - The call is descending, so we will only accept calls from the 
>>> policy server
>>> - Call rudder remote
>>> - prefix the remote output lines with <uuid>: to make sure the 
>>> caller can parse output during async call on multiple nodes
>>> - surround the output with json format lines and include return 
>>> code, duration and stderr (-> we should escape the output for use 
>>> within a json string)
>>>
>> Will it won't be able to traverse several relays, or am I not 
>> understanding correctly how it works? most notably, for one node 
>> only, what is the logic to reach the proper relay and sub-relays for 
>> the node ?
>
> It can since the call knows if the result comes from an API call or 
> from a command line call. It will not add anything to the result of an 
> API call.
> Side note, the json formatting if applied should be applied before 
> adding the prefix. I personally think that we should not have json at 
> all here since it will be a nightmare to manage it properly.

Hum, I'm not sure we are talking about the same thing.
Let's say you have a Root Server, two Relays A and B, and 2 subrelays A1 
and A2 under A, and a Node N under A1

How does the API knows, when you call from the Root server and ask to 
reach N:
- how to reach effectively N
- that A should relay the call to A1
- that A1 should send back the answer to A
- that A should send back the answer to the Root Server

Thank you !

Nicolas