fix: rename downloaded file using artifact name

[mdelapenya]

What does this PR do?

It renames the Beats binary downloaded from a GCP bucket, using the artifact name (i.e. elastic-agent-8.0.0-SNAPSHOT-x86_64.rpm) that was calculated before that.

I added the following test, but removed it as it's very dependendant on the network and the availability of GCP:

func TestFetchBeatsBinary(t *testing.T) {
	os.Setenv("BEATS_USE_CI_SNAPSHOTS", "true")
	os.Setenv("GITHUB_CHECK_SHA1", "b989478a3003c1b41722b7245586d58d832748a4")
	f, err := FetchBeatsBinary("elastic-agent-8.0.0-SNAPSHOT-x86_64.rpm", "elastic-agent", "8.0.0-SNAPSHOT", "8.0.0-SNAPSHOT", 3, true)
	assert.Nil(t, err)
	defer os.Remove(filepath.Dir(f))
	defer os.Unsetenv("BEATS_USE_CI_SNAPSHOTS")
	defer os.Unsetenv("GITHUB_CHECK_SHA1")

	// name has been sanitised
	assert.True(t, strings.HasSuffix(f, "elastic-agent-8.0.0-SNAPSHOT-x86_64.rpm"))
}

If you agree, we can keep it. Please let me know your thoughts

Why is it important?

In #1136 we added support for Docker-copying files to the running containers, but it was incomplete, as it only handled the name of regular files (with regular I mean those files downloaded from the Elastic repository). But when downloading from GCP buckets, the files contains many HTTP params in the file name, causing the Docker copy AND the execution of commands in the container against that copied file to fail.

Therefore, any PR or merge commit from Beats repo will fail the build because of that.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have run the Unit tests for the CLI, and they are passing locally
• I have run the End-2-End tests for the suite I'm working on, and they are passing locally
• I have noticed new Go dependencies (run make notice in the proper directory)

Author's Checklist

• [ ]

How to test this PR locally

Running a test using a binary for a commit:

SUITE="fleet" TAGS="backend_processes && centos && enroll" TIMEOUT_FACTOR=3 GITHUB_CHECK_SHA1=b989478a3003c1b41722b7245586d58d832748a4 LOG_LEVEL=TRACE BEATS_USE_CI_SNAPSHOTS=true DEVELOPER_MODE=true SKIP_PULL=true make -C e2e functional-test

Related issues

• Completes feat: use Docker copy to transfer binaries to containers #1136

Backports

Needs to be backported to 7.x and 7.13.x

[elasticmachine]

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• Build Cause: Started by user Manuel de la Peña

• Start Time: 2021-05-06T11:23:17.103+0000

• Duration: 20 min 51 sec

• Commit: 4f52d53

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Passed	159
Skipped	0
Total	159

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Passed	159
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Total	159