You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@ariatosca.apache.org by Steve Baillargeon <st...@ericsson.com> on 2017/10/19 17:39:20 UTC
Note template names
Hi
Node template names must be unique within a given service template.
What about the case when ST1 imports ST2 as follows.
ST1 has 2 node templates: template A derived from node type X and template B derived from node type Y.
ST2 has 1 node template: template A derived from node type Z .
Will this work?
Regards
Steve B
Re: Note template names
Posted by Thomas Nadeau <tn...@lucidvision.com>.
> On Oct 19, 2017, at 2:18 PM, Tal Liron <ta...@cloudify.co> wrote:
>
> Some good questions here. Let me try to break it down,
>
> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
> steve.baillargeon@ericsson.com> wrote:
>
>> Node template names must be unique within a given service template.
>>
>
> Yes. Actually, there is an "interesting" issue with this: in YAML, a dict
> could have multiple keys with the same name. What happens in that case is
> that subsequent keys (node template names in this case) override previous
> ones of the same name. So, you can syntactically have two node templates of
> the same name, but only one will count.
>
> We tried to find ways in ARIA to emit an error in this case, but actually
> it's very hard to do because it's a YAML spec issue that allows it.
It sounds like a warning in this case is the minimum “user friendly” thing to do.
Lots of compilers warn for “multiply (re)defined variable” etc…. In a large
set of templates, its unlikely for a human to realize this is happening.
—Tom
>
>
>> What about the case when ST1 imports ST2 as follows.
>> ST1 has 2 node templates: template A derived from node type X and template
>> B derived from node type Y.
>> ST2 has 1 node template: template A derived from node type Z .
>>
>
> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What we
> do in ARIA is merge the dicts, and again identical keys (node template
> names) will override without error. So, the final behavior will be
> undefined.
>
> However, I think that in this particular case ARIA can do something more,
> because we handle merging ourselves (it's not an issue of the YAML spec). I
> have opened a new JIRA about this:
> https://issues.apache.org/jira/browse/ARIA-390
Re: Note template names
Posted by Tal Liron <ta...@cloudify.co>.
Duplicate type names are also something we can warn about during import
merging. I included this in the aforementioned JIRA ticket.
On Tue, Oct 24, 2017 at 12:36 PM, Steve Baillargeon <
steve.baillargeon@ericsson.com> wrote:
> Hi Tal
> Thanks for the info.
>
> In summary, the last imported node template overrides the previous node
> template if they are using the same name.
> I feel this is the correct behavior and the only enhancement I see is an
> indication of such occurrence back to the "user".
> Another option is to add a system-wide configurable attribute to decide
> between 1) override and notify/log (default) versus 2) stop and send error
> message.
>
> What about node types.
> Say I want to override a normative node type with my own custom type using
> the same node type name (yes this is a strange case).
> Can I import a custom node type that will override a normative node type?
>
> -Steve
>
> -----Original Message-----
> From: Thomas Nadeau [mailto:tnadeau@lucidvision.com]
> Sent: Monday, October 23, 2017 1:38 PM
> To: dev@ariatosca.incubator.apache.org
> Subject: Re: Note template names
>
>
>
> > On Oct 23, 2017, at 1:12 PM, Tal Liron <ta...@cloudify.co> wrote:
> >
> > TOSCA says some things about how imports happen, but not that match. I
> > think we are aligned with the spec here.
>
> That is what I suspected, but best to check explicitly.
>
> > By the way, I'm quite proud of the implementation in ARIA: we handle
> > imports in a threadpool, so that if you are importing from many http
> > repositories at the same time, each download will happen simultaneously.
> > Performance is as optimal as it can be. (We are also caching the
> > results according to the conditional http request standard.)
>
> I had no reservations about that. 8)
>
> —Tom
>
>
> >
> > On Mon, Oct 23, 2017 at 12:06 PM, Thomas Nadeau
> > <tn...@gmail.com>
> > wrote:
> >
> >>
> >> Just for my own understanding, is the algorithm you describe
> >> used based on what TOSCA specifies,
> >> or is this our implementation detail? I ask because you can imagine
> >> process done
> >> one at a time, i.e.: per-file, but the processed results can of
> >> course, be different.
> >>
> >> —Tom
> >>
> >>
> >>
> >>> On Oct 23, 2017, at 12:46 PM, Tal Liron <ta...@cloudify.co> wrote:
> >>>
> >>> Yes, you can do that. Think of imports as being essentially like a
> >>> smart copy-paste from one YAML file to another. In the end, ARIA
> >>> treats it as just one big service template.
> >>>
> >>> In other words, the requirements-and-capabilities matching occurs
> >>> only after all imports were done and the final service template is
> valid.
> >>>
> >>> On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
> >>> steve.baillargeon@ericsson.com> wrote:
> >>>
> >>>> Thank you Tal
> >>>>
> >>>> Can ARIA handle the case when ST1 imports ST2 with a relationship
> >>>> (link) between source node template AA defined in ST1 and target
> >>>> node template
> >> BB
> >>>> defined in ST2?
> >>>> For instance, a SoftwareComponent node is defined in ST1 with a
> >>>> specific requirement to run on a Compute node that is defined in ST2.
> >>>>
> >>>> -Steve
> >>>>
> >>>> -----Original Message-----
> >>>> From: Tal Liron [mailto:tal@cloudify.co]
> >>>> Sent: Thursday, October 19, 2017 2:18 PM
> >>>> To: dev@ariatosca.incubator.apache.org
> >>>> Subject: Re: Note template names
> >>>>
> >>>> Some good questions here. Let me try to break it down,
> >>>>
> >>>> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
> >>>> steve.baillargeon@ericsson.com> wrote:
> >>>>
> >>>>> Node template names must be unique within a given service template.
> >>>>>
> >>>>
> >>>> Yes. Actually, there is an "interesting" issue with this: in YAML,
> >>>> a
> >> dict
> >>>> could have multiple keys with the same name. What happens in that
> >>>> case
> >> is
> >>>> that subsequent keys (node template names in this case) override
> >> previous
> >>>> ones of the same name. So, you can syntactically have two node
> >> templates of
> >>>> the same name, but only one will count.
> >>>>
> >>>> We tried to find ways in ARIA to emit an error in this case, but
> >> actually
> >>>> it's very hard to do because it's a YAML spec issue that allows it.
> >>>>
> >>>>
> >>>>> What about the case when ST1 imports ST2 as follows.
> >>>>> ST1 has 2 node templates: template A derived from node type X and
> >>>>> template B derived from node type Y.
> >>>>> ST2 has 1 node template: template A derived from node type Z .
> >>>>>
> >>>>
> >>>> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec.
> >>>> What we do in ARIA is merge the dicts, and again identical keys
> >>>> (node
> >> template
> >>>> names) will override without error. So, the final behavior will be
> >>>> undefined.
> >>>>
> >>>> However, I think that in this particular case ARIA can do something
> >> more,
> >>>> because we handle merging ourselves (it's not an issue of the YAML
> >> spec). I
> >>>> have opened a new JIRA about this:
> >>>> https://issues.apache.org/jira/browse/ARIA-390
> >>>>
> >>
> >>
>
>
RE: Note template names
Posted by Steve Baillargeon <st...@ericsson.com>.
Hi Tal
Thanks for the info.
In summary, the last imported node template overrides the previous node template if they are using the same name.
I feel this is the correct behavior and the only enhancement I see is an indication of such occurrence back to the "user".
Another option is to add a system-wide configurable attribute to decide between 1) override and notify/log (default) versus 2) stop and send error message.
What about node types.
Say I want to override a normative node type with my own custom type using the same node type name (yes this is a strange case).
Can I import a custom node type that will override a normative node type?
-Steve
-----Original Message-----
From: Thomas Nadeau [mailto:tnadeau@lucidvision.com]
Sent: Monday, October 23, 2017 1:38 PM
To: dev@ariatosca.incubator.apache.org
Subject: Re: Note template names
> On Oct 23, 2017, at 1:12 PM, Tal Liron <ta...@cloudify.co> wrote:
>
> TOSCA says some things about how imports happen, but not that match. I
> think we are aligned with the spec here.
That is what I suspected, but best to check explicitly.
> By the way, I'm quite proud of the implementation in ARIA: we handle
> imports in a threadpool, so that if you are importing from many http
> repositories at the same time, each download will happen simultaneously.
> Performance is as optimal as it can be. (We are also caching the
> results according to the conditional http request standard.)
I had no reservations about that. 8)
—Tom
>
> On Mon, Oct 23, 2017 at 12:06 PM, Thomas Nadeau
> <tn...@gmail.com>
> wrote:
>
>>
>> Just for my own understanding, is the algorithm you describe
>> used based on what TOSCA specifies,
>> or is this our implementation detail? I ask because you can imagine
>> process done
>> one at a time, i.e.: per-file, but the processed results can of
>> course, be different.
>>
>> —Tom
>>
>>
>>
>>> On Oct 23, 2017, at 12:46 PM, Tal Liron <ta...@cloudify.co> wrote:
>>>
>>> Yes, you can do that. Think of imports as being essentially like a
>>> smart copy-paste from one YAML file to another. In the end, ARIA
>>> treats it as just one big service template.
>>>
>>> In other words, the requirements-and-capabilities matching occurs
>>> only after all imports were done and the final service template is valid.
>>>
>>> On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
>>> steve.baillargeon@ericsson.com> wrote:
>>>
>>>> Thank you Tal
>>>>
>>>> Can ARIA handle the case when ST1 imports ST2 with a relationship
>>>> (link) between source node template AA defined in ST1 and target
>>>> node template
>> BB
>>>> defined in ST2?
>>>> For instance, a SoftwareComponent node is defined in ST1 with a
>>>> specific requirement to run on a Compute node that is defined in ST2.
>>>>
>>>> -Steve
>>>>
>>>> -----Original Message-----
>>>> From: Tal Liron [mailto:tal@cloudify.co]
>>>> Sent: Thursday, October 19, 2017 2:18 PM
>>>> To: dev@ariatosca.incubator.apache.org
>>>> Subject: Re: Note template names
>>>>
>>>> Some good questions here. Let me try to break it down,
>>>>
>>>> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
>>>> steve.baillargeon@ericsson.com> wrote:
>>>>
>>>>> Node template names must be unique within a given service template.
>>>>>
>>>>
>>>> Yes. Actually, there is an "interesting" issue with this: in YAML,
>>>> a
>> dict
>>>> could have multiple keys with the same name. What happens in that
>>>> case
>> is
>>>> that subsequent keys (node template names in this case) override
>> previous
>>>> ones of the same name. So, you can syntactically have two node
>> templates of
>>>> the same name, but only one will count.
>>>>
>>>> We tried to find ways in ARIA to emit an error in this case, but
>> actually
>>>> it's very hard to do because it's a YAML spec issue that allows it.
>>>>
>>>>
>>>>> What about the case when ST1 imports ST2 as follows.
>>>>> ST1 has 2 node templates: template A derived from node type X and
>>>>> template B derived from node type Y.
>>>>> ST2 has 1 node template: template A derived from node type Z .
>>>>>
>>>>
>>>> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec.
>>>> What we do in ARIA is merge the dicts, and again identical keys
>>>> (node
>> template
>>>> names) will override without error. So, the final behavior will be
>>>> undefined.
>>>>
>>>> However, I think that in this particular case ARIA can do something
>> more,
>>>> because we handle merging ourselves (it's not an issue of the YAML
>> spec). I
>>>> have opened a new JIRA about this:
>>>> https://issues.apache.org/jira/browse/ARIA-390
>>>>
>>
>>
Re: Note template names
Posted by Thomas Nadeau <tn...@lucidvision.com>.
> On Oct 23, 2017, at 1:12 PM, Tal Liron <ta...@cloudify.co> wrote:
>
> TOSCA says some things about how imports happen, but not that match. I
> think we are aligned with the spec here.
That is what I suspected, but best to check explicitly.
> By the way, I'm quite proud of the implementation in ARIA: we handle
> imports in a threadpool, so that if you are importing from many http
> repositories at the same time, each download will happen simultaneously.
> Performance is as optimal as it can be. (We are also caching the results
> according to the conditional http request standard.)
I had no reservations about that. 8)
—Tom
>
> On Mon, Oct 23, 2017 at 12:06 PM, Thomas Nadeau <tn...@gmail.com>
> wrote:
>
>>
>> Just for my own understanding, is the algorithm you describe used
>> based on what TOSCA specifies,
>> or is this our implementation detail? I ask because you can imagine
>> process done
>> one at a time, i.e.: per-file, but the processed results can of course, be
>> different.
>>
>> —Tom
>>
>>
>>
>>> On Oct 23, 2017, at 12:46 PM, Tal Liron <ta...@cloudify.co> wrote:
>>>
>>> Yes, you can do that. Think of imports as being essentially like a smart
>>> copy-paste from one YAML file to another. In the end, ARIA treats it as
>>> just one big service template.
>>>
>>> In other words, the requirements-and-capabilities matching occurs only
>>> after all imports were done and the final service template is valid.
>>>
>>> On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
>>> steve.baillargeon@ericsson.com> wrote:
>>>
>>>> Thank you Tal
>>>>
>>>> Can ARIA handle the case when ST1 imports ST2 with a relationship (link)
>>>> between source node template AA defined in ST1 and target node template
>> BB
>>>> defined in ST2?
>>>> For instance, a SoftwareComponent node is defined in ST1 with a specific
>>>> requirement to run on a Compute node that is defined in ST2.
>>>>
>>>> -Steve
>>>>
>>>> -----Original Message-----
>>>> From: Tal Liron [mailto:tal@cloudify.co]
>>>> Sent: Thursday, October 19, 2017 2:18 PM
>>>> To: dev@ariatosca.incubator.apache.org
>>>> Subject: Re: Note template names
>>>>
>>>> Some good questions here. Let me try to break it down,
>>>>
>>>> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
>>>> steve.baillargeon@ericsson.com> wrote:
>>>>
>>>>> Node template names must be unique within a given service template.
>>>>>
>>>>
>>>> Yes. Actually, there is an "interesting" issue with this: in YAML, a
>> dict
>>>> could have multiple keys with the same name. What happens in that case
>> is
>>>> that subsequent keys (node template names in this case) override
>> previous
>>>> ones of the same name. So, you can syntactically have two node
>> templates of
>>>> the same name, but only one will count.
>>>>
>>>> We tried to find ways in ARIA to emit an error in this case, but
>> actually
>>>> it's very hard to do because it's a YAML spec issue that allows it.
>>>>
>>>>
>>>>> What about the case when ST1 imports ST2 as follows.
>>>>> ST1 has 2 node templates: template A derived from node type X and
>>>>> template B derived from node type Y.
>>>>> ST2 has 1 node template: template A derived from node type Z .
>>>>>
>>>>
>>>> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What
>>>> we do in ARIA is merge the dicts, and again identical keys (node
>> template
>>>> names) will override without error. So, the final behavior will be
>>>> undefined.
>>>>
>>>> However, I think that in this particular case ARIA can do something
>> more,
>>>> because we handle merging ourselves (it's not an issue of the YAML
>> spec). I
>>>> have opened a new JIRA about this:
>>>> https://issues.apache.org/jira/browse/ARIA-390
>>>>
>>
>>
Re: Note template names
Posted by Tal Liron <ta...@cloudify.co>.
TOSCA says some things about how imports happen, but not that match. I
think we are aligned with the spec here.
By the way, I'm quite proud of the implementation in ARIA: we handle
imports in a threadpool, so that if you are importing from many http
repositories at the same time, each download will happen simultaneously.
Performance is as optimal as it can be. (We are also caching the results
according to the conditional http request standard.)
On Mon, Oct 23, 2017 at 12:06 PM, Thomas Nadeau <tn...@gmail.com>
wrote:
>
> Just for my own understanding, is the algorithm you describe used
> based on what TOSCA specifies,
> or is this our implementation detail? I ask because you can imagine
> process done
> one at a time, i.e.: per-file, but the processed results can of course, be
> different.
>
> —Tom
>
>
>
> > On Oct 23, 2017, at 12:46 PM, Tal Liron <ta...@cloudify.co> wrote:
> >
> > Yes, you can do that. Think of imports as being essentially like a smart
> > copy-paste from one YAML file to another. In the end, ARIA treats it as
> > just one big service template.
> >
> > In other words, the requirements-and-capabilities matching occurs only
> > after all imports were done and the final service template is valid.
> >
> > On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
> > steve.baillargeon@ericsson.com> wrote:
> >
> >> Thank you Tal
> >>
> >> Can ARIA handle the case when ST1 imports ST2 with a relationship (link)
> >> between source node template AA defined in ST1 and target node template
> BB
> >> defined in ST2?
> >> For instance, a SoftwareComponent node is defined in ST1 with a specific
> >> requirement to run on a Compute node that is defined in ST2.
> >>
> >> -Steve
> >>
> >> -----Original Message-----
> >> From: Tal Liron [mailto:tal@cloudify.co]
> >> Sent: Thursday, October 19, 2017 2:18 PM
> >> To: dev@ariatosca.incubator.apache.org
> >> Subject: Re: Note template names
> >>
> >> Some good questions here. Let me try to break it down,
> >>
> >> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
> >> steve.baillargeon@ericsson.com> wrote:
> >>
> >>> Node template names must be unique within a given service template.
> >>>
> >>
> >> Yes. Actually, there is an "interesting" issue with this: in YAML, a
> dict
> >> could have multiple keys with the same name. What happens in that case
> is
> >> that subsequent keys (node template names in this case) override
> previous
> >> ones of the same name. So, you can syntactically have two node
> templates of
> >> the same name, but only one will count.
> >>
> >> We tried to find ways in ARIA to emit an error in this case, but
> actually
> >> it's very hard to do because it's a YAML spec issue that allows it.
> >>
> >>
> >>> What about the case when ST1 imports ST2 as follows.
> >>> ST1 has 2 node templates: template A derived from node type X and
> >>> template B derived from node type Y.
> >>> ST2 has 1 node template: template A derived from node type Z .
> >>>
> >>
> >> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What
> >> we do in ARIA is merge the dicts, and again identical keys (node
> template
> >> names) will override without error. So, the final behavior will be
> >> undefined.
> >>
> >> However, I think that in this particular case ARIA can do something
> more,
> >> because we handle merging ourselves (it's not an issue of the YAML
> spec). I
> >> have opened a new JIRA about this:
> >> https://issues.apache.org/jira/browse/ARIA-390
> >>
>
>
Re: Note template names
Posted by Thomas Nadeau <tn...@gmail.com>.
Just for my own understanding, is the algorithm you describe used based on what TOSCA specifies,
or is this our implementation detail? I ask because you can imagine process done
one at a time, i.e.: per-file, but the processed results can of course, be different.
—Tom
> On Oct 23, 2017, at 12:46 PM, Tal Liron <ta...@cloudify.co> wrote:
>
> Yes, you can do that. Think of imports as being essentially like a smart
> copy-paste from one YAML file to another. In the end, ARIA treats it as
> just one big service template.
>
> In other words, the requirements-and-capabilities matching occurs only
> after all imports were done and the final service template is valid.
>
> On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
> steve.baillargeon@ericsson.com> wrote:
>
>> Thank you Tal
>>
>> Can ARIA handle the case when ST1 imports ST2 with a relationship (link)
>> between source node template AA defined in ST1 and target node template BB
>> defined in ST2?
>> For instance, a SoftwareComponent node is defined in ST1 with a specific
>> requirement to run on a Compute node that is defined in ST2.
>>
>> -Steve
>>
>> -----Original Message-----
>> From: Tal Liron [mailto:tal@cloudify.co]
>> Sent: Thursday, October 19, 2017 2:18 PM
>> To: dev@ariatosca.incubator.apache.org
>> Subject: Re: Note template names
>>
>> Some good questions here. Let me try to break it down,
>>
>> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
>> steve.baillargeon@ericsson.com> wrote:
>>
>>> Node template names must be unique within a given service template.
>>>
>>
>> Yes. Actually, there is an "interesting" issue with this: in YAML, a dict
>> could have multiple keys with the same name. What happens in that case is
>> that subsequent keys (node template names in this case) override previous
>> ones of the same name. So, you can syntactically have two node templates of
>> the same name, but only one will count.
>>
>> We tried to find ways in ARIA to emit an error in this case, but actually
>> it's very hard to do because it's a YAML spec issue that allows it.
>>
>>
>>> What about the case when ST1 imports ST2 as follows.
>>> ST1 has 2 node templates: template A derived from node type X and
>>> template B derived from node type Y.
>>> ST2 has 1 node template: template A derived from node type Z .
>>>
>>
>> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What
>> we do in ARIA is merge the dicts, and again identical keys (node template
>> names) will override without error. So, the final behavior will be
>> undefined.
>>
>> However, I think that in this particular case ARIA can do something more,
>> because we handle merging ourselves (it's not an issue of the YAML spec). I
>> have opened a new JIRA about this:
>> https://issues.apache.org/jira/browse/ARIA-390
>>
Re: Note template names
Posted by Tal Liron <ta...@cloudify.co>.
Yes, you can do that. Think of imports as being essentially like a smart
copy-paste from one YAML file to another. In the end, ARIA treats it as
just one big service template.
In other words, the requirements-and-capabilities matching occurs only
after all imports were done and the final service template is valid.
On Mon, Oct 23, 2017 at 10:45 AM, Steve Baillargeon <
steve.baillargeon@ericsson.com> wrote:
> Thank you Tal
>
> Can ARIA handle the case when ST1 imports ST2 with a relationship (link)
> between source node template AA defined in ST1 and target node template BB
> defined in ST2?
> For instance, a SoftwareComponent node is defined in ST1 with a specific
> requirement to run on a Compute node that is defined in ST2.
>
> -Steve
>
> -----Original Message-----
> From: Tal Liron [mailto:tal@cloudify.co]
> Sent: Thursday, October 19, 2017 2:18 PM
> To: dev@ariatosca.incubator.apache.org
> Subject: Re: Note template names
>
> Some good questions here. Let me try to break it down,
>
> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
> steve.baillargeon@ericsson.com> wrote:
>
> > Node template names must be unique within a given service template.
> >
>
> Yes. Actually, there is an "interesting" issue with this: in YAML, a dict
> could have multiple keys with the same name. What happens in that case is
> that subsequent keys (node template names in this case) override previous
> ones of the same name. So, you can syntactically have two node templates of
> the same name, but only one will count.
>
> We tried to find ways in ARIA to emit an error in this case, but actually
> it's very hard to do because it's a YAML spec issue that allows it.
>
>
> > What about the case when ST1 imports ST2 as follows.
> > ST1 has 2 node templates: template A derived from node type X and
> > template B derived from node type Y.
> > ST2 has 1 node template: template A derived from node type Z .
> >
>
> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What
> we do in ARIA is merge the dicts, and again identical keys (node template
> names) will override without error. So, the final behavior will be
> undefined.
>
> However, I think that in this particular case ARIA can do something more,
> because we handle merging ourselves (it's not an issue of the YAML spec). I
> have opened a new JIRA about this:
> https://issues.apache.org/jira/browse/ARIA-390
>
RE: Note template names
Posted by Steve Baillargeon <st...@ericsson.com>.
Thank you Tal
Can ARIA handle the case when ST1 imports ST2 with a relationship (link) between source node template AA defined in ST1 and target node template BB defined in ST2?
For instance, a SoftwareComponent node is defined in ST1 with a specific requirement to run on a Compute node that is defined in ST2.
-Steve
-----Original Message-----
From: Tal Liron [mailto:tal@cloudify.co]
Sent: Thursday, October 19, 2017 2:18 PM
To: dev@ariatosca.incubator.apache.org
Subject: Re: Note template names
Some good questions here. Let me try to break it down,
On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon < steve.baillargeon@ericsson.com> wrote:
> Node template names must be unique within a given service template.
>
Yes. Actually, there is an "interesting" issue with this: in YAML, a dict could have multiple keys with the same name. What happens in that case is that subsequent keys (node template names in this case) override previous ones of the same name. So, you can syntactically have two node templates of the same name, but only one will count.
We tried to find ways in ARIA to emit an error in this case, but actually it's very hard to do because it's a YAML spec issue that allows it.
> What about the case when ST1 imports ST2 as follows.
> ST1 has 2 node templates: template A derived from node type X and
> template B derived from node type Y.
> ST2 has 1 node template: template A derived from node type Z .
>
Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What we do in ARIA is merge the dicts, and again identical keys (node template
names) will override without error. So, the final behavior will be undefined.
However, I think that in this particular case ARIA can do something more, because we handle merging ourselves (it's not an issue of the YAML spec). I have opened a new JIRA about this:
https://issues.apache.org/jira/browse/ARIA-390
Re: Note template names
Posted by Tal Liron <ta...@cloudify.co>.
Some good questions here. Let me try to break it down,
On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
steve.baillargeon@ericsson.com> wrote:
> Node template names must be unique within a given service template.
>
Yes. Actually, there is an "interesting" issue with this: in YAML, a dict
could have multiple keys with the same name. What happens in that case is
that subsequent keys (node template names in this case) override previous
ones of the same name. So, you can syntactically have two node templates of
the same name, but only one will count.
We tried to find ways in ARIA to emit an error in this case, but actually
it's very hard to do because it's a YAML spec issue that allows it.
> What about the case when ST1 imports ST2 as follows.
> ST1 has 2 node templates: template A derived from node type X and template
> B derived from node type Y.
> ST2 has 1 node template: template A derived from node type Z .
>
Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What we
do in ARIA is merge the dicts, and again identical keys (node template
names) will override without error. So, the final behavior will be
undefined.
However, I think that in this particular case ARIA can do something more,
because we handle merging ourselves (it's not an issue of the YAML spec). I
have opened a new JIRA about this:
https://issues.apache.org/jira/browse/ARIA-390