KEP-24: Enhanced Operator Parameters #1356

nfnt · 2020-02-21T13:20:39Z

What this PR does / why we need it:
This KEP aims to improve the use-cases that can be covered by parameters. By supporting additional types, templates can access lists and dictionaries. Furthermore, validation can be implemented for known types.

As needed by #1349, #988, #951
Related: #1221; this KEP would allow to iterate over the items of a dict to create YAML, but having a toYAML template function would still be beneficial

This KEP aims to improve the use-cases that can be covered by parameters. By supporting additional types, templates can access lists and dictionaries. Furthermore, validation can be implemented for known types. Signed-off-by: Jan Schlicht <jan@d2iq.com>

Signed-off-by: Jan Schlicht <jan@d2iq.com>

keps/0024-parameter-enhancement.md

porridge · 2020-02-21T13:36:16Z

keps/0024-parameter-enhancement.md

+
+### Provide Parameter Validation
+
+Adding types for lists and dictionaries provides access to the items of these structures in templates. Adding types like integers won't provide benefits for templating, but would allow for input value validation. KUDO could, e.g., validate that an integer isn't too large, that a list doesn't have too many entries, or that a string isn't too long. Adding parameter validation is independent from adding parameter types.


Another thing useful to a user would be to verify that more complex objects passed as parameters have correct structure, even before it's merged with the rest of the (potentially huge) template (at which point it might be a little overwhelming to figure out what an error message means).

keps/0024-parameter-enhancement.md

Signed-off-by: Jan Schlicht <jan@d2iq.com>

porridge · 2020-02-25T10:08:58Z

keps/0024-parameter-enhancement.md

@@ -0,0 +1,146 @@
+---
+kep-number: 24


This should be draft-YYYYMMDD according to the KEP process doc. 🤔

Oh wait, not necessarily 🤦‍♂️

Signed-off-by: Jan Schlicht <jan@d2iq.com>

akirillov

Thanks, @nfnt. I have a generic question regarding the passing of enhanced parameters at the moment of installation of an operator. Looking at the examples in #1349 with complex NODE_TOPOLOGY parameter, or at nodeSelector/podAnnotations from #1221, how users are supposed to pass these parameters via -p flags of KUDO CLI?

Supporting some sort of value files with defaults override can be a possible solution. Is this KEP addressing complex values specification by users?

Signed-off-by: Jan Schlicht <jan@d2iq.com>

nfnt · 2020-02-26T10:23:23Z

@akirillov That's a good question! @porridge asked that one as well. I added some notes that it's necessary to better support these parameter values. See also #1364 which is a KEP about adding support for loading parameter values from a file.

Signed-off-by: Jan Schlicht <jan@d2iq.com>

porridge · 2020-02-27T06:32:07Z

Supporting some sort of value files with defaults override can be a possible solution. Is this KEP addressing complex values specification by users?

@akirillov as mentioned by @nfnt #1364 addresses passing complex values.
The other side of the coin - actually being able to conveniently use those complex values - is covered by the KEP in #1363 .

zmalik · 2020-02-27T12:39:13Z

keps/0024-parameter-enhancement.md

+
+### Support Optional Parameter Types
+
+By adding an optional `type` field to the list of parameters, parameter types can be specified. If this field isn't present, it defaults to the `string` type. Other types like `list`, `dict` or `integer` are possible. KUDO's renderer uses the type information to convert the string value to the respective type. For example, for the `dict` type, the input value would be YAML that is unmarshalled to a `map[string]interface{}`. Go's template engine allows to access and iterate list and dictionary items.


➕to defaults to string type for a strong retro-compatibility

What about the types of elements of list and dict? We will always use them as string? In that case, should we mention it here

I don't think types of elements of list and dict should be guaranteed to be strings.
Keeping them arbitrary is necessary to be able to support #1221 (and #951).

Then we should allow users to specify the structure of those elements to be a custom struct or Integer or String. Or at least specify how it would work.
cc: @nfnt

Elements of list and dicts can have other types than string. Because they will be provided as YAML and YAML supports multiple types.

zmalik

LGTM

porridge

This is awesome, I added a few inline suggestions.

keps/0024-parameter-enhancement.md

Co-Authored-By: Marcin Owsiany <mowsiany@D2iQ.com>

Signed-off-by: Jan Schlicht <jan@d2iq.com>

This KEP aims to improve the use-cases that can be covered by parameters. By supporting additional types, templates can access lists and dictionaries. Furthermore, validation can be implemented for known types. Co-Authored-By: Marcin Owsiany <mowsiany@D2iQ.com> Signed-off-by: Jan Schlicht <jan@d2iq.com> Signed-off-by: Thomas Runyon <runyontr@gmail.com>

nfnt added kind/kep Kudo Enhancement kep/24 Map and array parameter types labels Feb 21, 2020

nfnt requested review from alenkacz, gerred, kensipe and zen-dog as code owners February 21, 2020 13:20

nfnt self-assigned this Feb 21, 2020

nfnt requested review from akirillov, porridge and zmalik February 21, 2020 13:20

Clarify non-goal

403237e

Signed-off-by: Jan Schlicht <jan@d2iq.com>

porridge reviewed Feb 21, 2020

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Clarified some sentences

741e9bf

Signed-off-by: Jan Schlicht <jan@d2iq.com>

nfnt mentioned this pull request Feb 25, 2020

Support arbitrary YAML as parameter values #1351

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porridge reviewed Feb 25, 2020

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Remove pipe

e63cb23

Signed-off-by: Jan Schlicht <jan@d2iq.com>

akirillov reviewed Feb 25, 2020

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Notes about parameter value input

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Signed-off-by: Jan Schlicht <jan@d2iq.com>

Update ToC

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Signed-off-by: Jan Schlicht <jan@d2iq.com>

zmalik reviewed Feb 27, 2020

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zmalik approved these changes Feb 27, 2020

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porridge approved these changes Feb 28, 2020

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Jan Schlicht and others added 2 commits February 28, 2020 11:38

Apply suggestions from code review

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Co-Authored-By: Marcin Owsiany <mowsiany@D2iQ.com>

Use strings for default values

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Signed-off-by: Jan Schlicht <jan@d2iq.com>

nfnt merged commit 3b159d5 into master Mar 2, 2020

nfnt deleted the nfnt/kep-24-parameter-enhancements branch March 2, 2020 09:08

porridge mentioned this pull request Mar 3, 2020

Support typed parameter values #1376

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KEP-24: Enhanced Operator Parameters #1356

KEP-24: Enhanced Operator Parameters #1356

nfnt commented Feb 21, 2020 •

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		### Provide Parameter Validation

		Adding types for lists and dictionaries provides access to the items of these structures in templates. Adding types like integers won't provide benefits for templating, but would allow for input value validation. KUDO could, e.g., validate that an integer isn't too large, that a list doesn't have too many entries, or that a string isn't too long. Adding parameter validation is independent from adding parameter types.


		### Support Optional Parameter Types

		By adding an optional `type` field to the list of parameters, parameter types can be specified. If this field isn't present, it defaults to the `string` type. Other types like `list`, `dict` or `integer` are possible. KUDO's renderer uses the type information to convert the string value to the respective type. For example, for the `dict` type, the input value would be YAML that is unmarshalled to a `map[string]interface{}`. Go's template engine allows to access and iterate list and dictionary items.

		@@ -0,0 +1,146 @@
		---
		kep-number: 24

KEP-24: Enhanced Operator Parameters #1356

KEP-24: Enhanced Operator Parameters #1356

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nfnt commented Feb 21, 2020 •

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