Stabilized the artifact ordering during the compilation

[Ark-kun]

This change makes the order of output artifacts stable in Python 3.5.
The sample test seems to be relying on the artifact ordering (it tries to read the first artifact without looking at the name).
With this change the order is always the preserved and stable.

This change is 

[Ark-kun]

/test kubeflow-pipeline-sample-test

[gaoning777]

Could you explain a bit why we need this change?

[Ark-kun]

Could you explain a bit why we need this change?

As the title indicates, this makes the order of output artifacts stable in Python 3.5.
The sample test seems to be relying on the artifact ordering (it tries to read the first artifact without looking at the name).
With this change the order is always the preserved and stable.

[gaoning777]

The sample tests do not rely on the strict ordering of the artifacts but instead searches for the artifact.

pipelines/test/sample-test/utils.py

Line 28 in b1e4a56

for artifact in node['outputs']['artifacts']:

[Ark-kun]

The sample tests do not rely on the strict ordering of the artifacts but instead searches for the artifact.

They did until I fixed them on Friday night:

pipelines/test/sample-test/utils.py

Line 28 in 633e2dd

s3_data = workflow_json['status']['nodes'][key]['outputs']['artifacts'][0]['s3']

Also the compiler tests do rely on the ordering.

Generally it's a good idea to have stable execution where multiple program runs with the same arguments produce same results.

[gaoning777]

I see. Thanks for the explanation.

[gaoning777]

/lgtm

[Ark-kun]

/approve

[k8s-ci-robot]

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Ark-kun

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• sdk/OWNERS [Ark-kun]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment