Drone not parsing template data correctly

Ideas
1

Hello,

I’m using template.

I’m currently writing inline JSON that I parse with “std.parseJson” in Jsonnet. This seems unnecessary.

kind: template
load: test.jsonnet
data:
  builds: >
    [
      {
        "name": "build1"
      },
      {
        "name": "build2"
      }
    ]

In my opinion it would be better to just specify as below.

kind: template
load: test.jsonnet
data:
  builds:
    - name: build1
    - name: build2

And then parse from Jsonnet.

local builds = std.parseJson(std.extVar("input.builds"));
...

Right now objects and lists doesn’t seem to get serialized. I guess my question is, could Drone serialize them as JSON before parsing args to Jsonnet?

2

Right now objects and lists doesn’t seem to get serialized.

this is by design because, unlike jsonnet, starlark is able to handle nested data. If you want to work with nested template data you might consider starlark instead.

3

Do you have any example on how to parse this nested data using starlark?

4

it doesn’t need to be parsed, it is loaded into starlark as structured data. for example ctx.input.builds[0]

5

Well that seems like a better solution. Will try it out.

Thanks for the help.

6

I can’t get it to work in Starlark either. If i specify ctx.input.builds[0] or just ctx.input.builds i get the error:

"input" struct has no .builds attribute

If I don’t use nested list or object, it works.

.drone.yml I’m using.

kind: template
load: test.starlark
data:
  builds:
    - name: build1
    - name: build2
8

Hey @mortenfryd

I’ve identified the issue and will be pushing out a fix soon.

Cheers,
Eoin

9

Sounds great, thanks :slight_smile:

10

Hey @mortenfryd

Would it be possible for you to provide me with the desired end state, the drone.yml & template you wish to get to? Not the entire end state but a working example so I can make sure the change has fully met the requirement.

Cheers,
Eoin

11

Sure.

I have this simple template that should do the job.

.drone.yml

kind: template
load: plugin.starlark
data:
  name: "stepname"
  env:
    foo: foo
    bar: bar
  cmds:
    - echo foo bar
    - ls

plugin.starlark

def main(ctx):
  return {
    "kind": "pipeline",
    "name": "build",
    "steps": [
      {
        "name": ctx.input.name,
        "image": "alpine",
        "environment": ctx.input.env,
        "commands": ctx.input.cmds
      }
    ]
  }

Also it would be nice if it worked with nested objects in lists, like below. But i assume that will work too… maybe :slight_smile: ?
.drone.yml

kind: template
load: plugin.starlark
data:
  name: "stepname"
  builds:
    - name: test123
    - name: test1234
12

@mortenfryd
If you pull the latest, I’ve added this enhancement to templating.

13

Thanks. Will check it out asap.

14

Hi @eoinmcafee00,

I can confirm that the fix works as expected.

/Morten