Open Stack

On 05/12/13 17:00 +0000, Steven Hardy wrote:
>On Thu, Dec 05, 2013 at 04:11:37PM +0000, ELISHA, Moshe (Moshe) wrote:
>> Hey,
>>
>> I really liked the v2 Heat API (as proposed in Create a new v2 Heat API<https://blueprints.launchpad.net/heat/+spec/v2api>) and I think it makes a lot of sense.
>>
>> One of the proposed changes is to "Remove template_url from the request POST", so the template will be passed using the "template" parameter in the request body.
>>
>> Could someone please elaborate how exactly Heat Orchestration Templates written in YAML will be embedded in the body?
>
>In exactly the same way they are now, try creating a stack using a HOT yaml
>template, with --debug enabled via python heatclient and you'll see what I
>mean:
>
>wget https://raw.github.com/openstack/heat-templates/master/hot/F18/WordPress_Native.yaml
>
>heat --debug stack-create -P "key_name=userkey" -f ./WordPress_Native.yaml wp1
>
>This works fine now, so there's nothing to do to support this.

Given the talks about Heater/appstore/glance-templates it would be
good to be able to pass a references to one of those systems so
the user doesn't have to upload to glance, then send a copy to heat.

so just pass a template_id like how nova.boot() takes an image_id.

-Angus

>
>> As I understand the YAML template should be inserted as string otherwise JSON parsers will not be able to parse the JSON body.
>> If indeed the template is inserted as string, as far as I know, JSON does not support multiline strings and the available workarounds are not so pretty and require escaping.
>> The escaping issue gets more complicated when "UserData" is used in the YAML.
>
>It's just a string, we do the parsing inside the heat-engine, with either
>json or yaml parser, depending on the content of the string.
>
>> Will the "template_url" be removed and if so how will the "template" contain the YAML template?
>
>Well, this is a good opportunity to discuss it, since removing it was only
>one persons idea (mine ;) and we haven't discussed it much in the team.
>
>My argument for removing it, is:
>
>- We already resolve URLs for environment files in python-heatclient, and
>  pass them in the "files" parameter, so lets to the same for the template.
>
>- In real world deployments, assuming the heat-api has access to
>  whatever URL you pass may not be reasonable (or secure, ideally we don't
>  want the heat hitting random user-provided URLs)
>
>- We are tying up service resources doing a chunked download of a template,
>  when this overhead can be in the client, then we just have to check the
>  string length provided in the request in the API. When you consider many
>  concurrent requests to heat containing template_url, this will probably
>  result in a significant performance advantage.
>
>The python CLI/API could be unmodified, if someone passes template_url, we just
>download it in the client and pass the result in the POST to the heat API.
>
>So essentially it shouldn't impact users at all, it's just moving the
>processing of template_url from heat-api to python-heatclient.
>
>If anyone has some counter-arguments, lets discuss! :)
>
>Steve
>
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