Yaml templates sharing container image

[Abacn]

Part of #2279

[gemini-code-assist]

Summary of Changes

Hello @Abacn, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a crucial enhancement for Dataflow YAML templates, enabling them to share a common container image. This is achieved by introducing a dynamic mechanism for the Python launcher to identify and load the appropriate YAML definition at runtime, supported by a centralized system for managing container-specific resources and an index file within the container. The change streamlines the deployment process and improves efficiency for YAML-based pipelines.

Highlights

• Shared Container Image for YAML Templates: Multiple YAML-based Dataflow templates can now share a single container image, reducing build and deployment overhead by centralizing common resources.
• Dynamic YAML Template Selection: The Python launcher for YAML templates has been updated to dynamically select the correct YAML definition file at runtime based on pipeline labels, rather than relying on a fixed 'template.yaml' file.
• Centralized Container Resource Management: A new ContainerStageTracker class manages the files and metadata associated with shared container images, including compatibility checks for templates sharing the same container.
• Automated YAML Index Generation: A yaml-templates-index JSON file is now generated and included in shared container images, mapping template names to their respective YAML definition files for dynamic lookup.
• Refactored YAML Template Staging Logic: The Maven plugin's logic for preparing and staging YAML template files and Dockerfiles has been significantly refactored to support the new shared container model and dynamic file inclusion.

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[codecov]

Codecov Report

❌ Patch coverage is 53.08642% with 38 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.92%. Comparing base (ba21420) to head (facf696).
⚠️ Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
...loud/teleport/plugin/maven/TemplatesStageMojo.java	53.08%	29 Missing and 9 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #3268      +/-   ##
============================================
- Coverage     50.94%   50.92%   -0.02%     
- Complexity     5159     5546     +387     
============================================
  Files           977      979       +2     
  Lines         60405    60553     +148     
  Branches       6608     6634      +26     
============================================
+ Hits          30772    30837      +65     
- Misses        27479    27547      +68     
- Partials       2154     2169      +15     

Components	Coverage Δ
spanner-templates	70.83% <ø> (-0.20%)	⬇️
spanner-import-export	68.91% <ø> (-0.15%)	⬇️
spanner-live-forward-migration	80.04% <ø> (-0.08%)	⬇️
spanner-live-reverse-replication	77.58% <ø> (-0.15%)	⬇️
spanner-bulk-migration	88.08% <ø> (-0.38%)	⬇️

Files with missing lines	Coverage Δ
...gle/cloud/teleport/plugin/DockerfileGenerator.java	90.00% <ø> (ø)
...loud/teleport/plugin/maven/TemplatesStageMojo.java	17.87% <53.08%> (+4.74%)	⬆️

... and 16 files with indirect coverage changes

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[Abacn]

R: @derrickaw

[Abacn]

The latest commit fixed an edge case preventing container compatibility check working when a compatible template came first then an incompatible one reuse container (not happening in current Templates).

KafkaToIceberg Yaml test failed with managed transform launcher fail, a combination of b/479594634 (serverless launcher failing) and stock out of the region (GCE launcher cannot be provisioned) caused the issue, not related to this change

Dataflow is unable to process the managed transform(s) ref_AppliedPTransform_WriteToIceberg-SchemaAwareExternalTransform-beam-transform-managed-v1_6(beam:schematransform:org.apache.beam:iceberg_write:v1),ref_AppliedPTransform_ReadFromKafka-beam-schematransform-org-apache-beam-kafka_read-v1_3(beam:schematransform:org.apache.beam:kafka_read:v1) due to an internal error. Because the upgrade failed, the new job or the update request has been rejected. To troubleshoot, see https://cloud.google.com/dataflow/docs/guides/common-errors#managed-transforms-upgrade.
2026-01-29 20:47:08.047 EST
Unknown error in operation 'operation-1769737619256-6499126243540-62553c5b-cc61bf89': [ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS] 'The zone 'projects/cloud-teleport-testing/zones/us-west2-b' does not have enough resources available to fulfill the request.  '(resource type:compute)'.'

update: second attempt failed one test, same reason:

Unknown error in operation 'operation-1769804533087-649a0ba843b9c-cc99d86b-07e149cc': [ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS] 'The zone 'projects/cloud-teleport-testing/zones/us-west2-b' does not have enough resources available to fulfill the request. 

[Abacn]

It appears this PR triggered a weird bug of template parameter corruption: https://github.com/GoogleCloudPlatform/DataflowTemplates/actions/runs/21535675203

"details": [
    {
      "@type": "type.googleapis.com/google.dataflow.v1beta3.InvalidTemplateParameters",
      "parameterViolations": [
        {
          "description": "Conditional parameter had an invalid trigger value: 'AVRO_BINARY_ENCODING'",
          "parameter": "schemaFormat"
        }
      ]
    }
  ],

checking the template json, this PR caused json fields ordered alphabetically.

Previously

{
        "name": "readBootstrapServerAndTopic",
        "groupName": "Source",
        "label": "Source Kafka Topic",
        "helpText": "Kafka Topic to read the input from.",
        "parentTriggerValues": [
          ""
        ],
        "paramType": "KAFKA_READ_TOPIC"
      },

now

{
                "groupName": "Source",
                "helpText": "Kafka Topic to read the input from.",
                "label": "Source Kafka Topic",
                "name": "readBootstrapServerAndTopic",
                "paramType": "KAFKA_READ_TOPIC",
                "parentTriggerValues": [
                    ""
                ]
            },

This is due to a line added during debugging forgot to remove: https://github.com/GoogleCloudPlatform/DataflowTemplates/pull/3268/changes#diff-e974a7cb17b5eaece9f4bf8e4c0952d47a5de1313b51a8ac51fe0e872c3240f9R598

causing template spec file not overriden (and latter steps, e.g. SBOM/scanning skipped. Though there were not enabled in test run either)

This should still work as templates is built via gcloud dataflow flex-template build command as we are not actively changing template request proto recently. However it generates a invalid json seen by router. We should revisit it afterwards.

EDIT: reverting this PR the test failure persists: go/templates-pr/3286