[system tests] Allow setting an optional prefix for the service TestRunID

[mrodm]

This PR allows to customize the Service TestRunID used in system tests to include a prefix string. This prefix is defined via environment variable:

export ELASTIC_PACKAGE_PREFIX_SERVICE_TEST_RUN_ID=1a2b

How to test this PR locally

elastic-package stack up -v -d
cd test/packages/parallel/terraform_local

export ELASTIC_PACKAGE_PREFIX_SERVICE_TEST_RUN_ID=1a2b
elastic-package test system -v

While the system tests are running you can check the files created by terraform at:

ls -l ~/.elastic-package/profiles/default/service_logs/agent-terraform_local-local-*/file*

it should countain a prefix of 9 digits (e.g. file-1a2b21464.log).

or via the Discover view in Kibana filtering by data_stream.dataset : "terraform_local.local", and it should contain a log field similar to:

    "log": {
      "file": {
        "path": "/tmp/service_logs/file-1a2b21464.log"
      },
      "offset": 0
    },

Author's Checklist

• Test with a package creating resources in Terraform
• Test with packages defined in the integrations repository

[mrodm]

In case of using the terraform service deployer, a part of updating the RunID used in as terraform variable, the alias used to render the policy templates in tests needs to be set to the same value as the terraform variable. This is needed for instance for aws.ec2_metrics that filters by the some resource name.

[mrodm]

This function is used also in other places (e.g. adding a random suffix to policies), those can be kept as they are now.

For instance:

elastic-package/internal/testrunner/runners/system/tester.go

Line 1021 in be35e60

Namespace: common.CreateTestRunID(),

[elasticmachine]

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• Commit: cb94a11

cc @mrodm