Add when conditions to prepare

[SPPearce]

As noted in #56 , the BWA index generation happens every time (and doesn't seem to cache, which makes it even more annoying).
This PR adds when conditions to the prepare genome steps so they don't run if the appropriate parameters are passed.

[github-actions]

nf-core lint overall result: Passed ✅ ⚠️

Posted for pipeline commit 916a1bf

+| ✅ 169 tests passed       |+
#| ❔   8 tests were ignored |#
!| ❗   4 tests had warnings |!

❗ Test warnings:

• nextflow_config - Config manifest.version should end in dev: 1.0.0
• readme - README contains the placeholder zenodo.XXXXXXX. This should be replaced with the zenodo doi (after the first release).
• pipeline_todos - TODO string in README.md: Add citation for pipeline after first release. Uncomment lines below and update Zenodo doi and badge at the top of this file.
• pipeline_todos - TODO string in output.md: Write this documentation describing your workflow's output

❔ Tests ignored:

• files_exist - File is ignored: .github/workflows/awsfulltest.yml
• files_exist - File is ignored: .github/workflows/awstest.yml
• files_exist - File is ignored: conf/modules/modules.config
• files_unchanged - File ignored due to lint config: .github/PULL_REQUEST_TEMPLATE.md
• files_unchanged - File ignored due to lint config: assets/nf-core-fastquorum_logo_light.png
• files_unchanged - File ignored due to lint config: .gitignore or .prettierignore
• actions_ci - actions_ci
• template_strings - template_strings

✅ Tests passed:

• files_exist - File found: .gitattributes
• files_exist - File found: .gitignore
• files_exist - File found: .nf-core.yml
• files_exist - File found: .editorconfig
• files_exist - File found: .prettierignore
• files_exist - File found: .prettierrc.yml
• files_exist - File found: CHANGELOG.md
• files_exist - File found: CITATIONS.md
• files_exist - File found: CODE_OF_CONDUCT.md
• files_exist - File found: LICENSE or LICENSE.md or LICENCE or LICENCE.md
• files_exist - File found: nextflow_schema.json
• files_exist - File found: nextflow.config
• files_exist - File found: README.md
• files_exist - File found: .github/.dockstore.yml
• files_exist - File found: .github/CONTRIBUTING.md
• files_exist - File found: .github/ISSUE_TEMPLATE/bug_report.yml
• files_exist - File found: .github/ISSUE_TEMPLATE/config.yml
• files_exist - File found: .github/ISSUE_TEMPLATE/feature_request.yml
• files_exist - File found: .github/PULL_REQUEST_TEMPLATE.md
• files_exist - File found: .github/workflows/branch.yml
• files_exist - File found: .github/workflows/ci.yml
• files_exist - File found: .github/workflows/linting_comment.yml
• files_exist - File found: .github/workflows/linting.yml
• files_exist - File found: assets/email_template.html
• files_exist - File found: assets/email_template.txt
• files_exist - File found: assets/sendmail_template.txt
• files_exist - File found: assets/nf-core-fastquorum_logo_light.png
• files_exist - File found: conf/modules.config
• files_exist - File found: conf/test.config
• files_exist - File found: conf/test_full.config
• files_exist - File found: docs/images/nf-core-fastquorum_logo_light.png
• files_exist - File found: docs/images/nf-core-fastquorum_logo_dark.png
• files_exist - File found: docs/output.md
• files_exist - File found: docs/README.md
• files_exist - File found: docs/README.md
• files_exist - File found: docs/usage.md
• files_exist - File found: main.nf
• files_exist - File found: assets/multiqc_config.yml
• files_exist - File found: conf/base.config
• files_exist - File found: conf/igenomes.config
• files_exist - File found: modules.json
• files_exist - File not found check: .github/ISSUE_TEMPLATE/bug_report.md
• files_exist - File not found check: .github/ISSUE_TEMPLATE/feature_request.md
• files_exist - File not found check: .github/workflows/push_dockerhub.yml
• files_exist - File not found check: .markdownlint.yml
• files_exist - File not found check: .nf-core.yaml
• files_exist - File not found check: .yamllint.yml
• files_exist - File not found check: bin/markdown_to_html.r
• files_exist - File not found check: conf/aws.config
• files_exist - File not found check: docs/images/nf-core-fastquorum_logo.png
• files_exist - File not found check: lib/Checks.groovy
• files_exist - File not found check: lib/Completion.groovy
• files_exist - File not found check: lib/NfcoreTemplate.groovy
• files_exist - File not found check: lib/Utils.groovy
• files_exist - File not found check: lib/Workflow.groovy
• files_exist - File not found check: lib/WorkflowMain.groovy
• files_exist - File not found check: lib/WorkflowFastquorum.groovy
• files_exist - File not found check: parameters.settings.json
• files_exist - File not found check: pipeline_template.yml
• files_exist - File not found check: Singularity
• files_exist - File not found check: lib/nfcore_external_java_deps.jar
• files_exist - File not found check: .travis.yml
• nextflow_config - Config variable found: manifest.name
• nextflow_config - Config variable found: manifest.nextflowVersion
• nextflow_config - Config variable found: manifest.description
• nextflow_config - Config variable found: manifest.version
• nextflow_config - Config variable found: manifest.homePage
• nextflow_config - Config variable found: timeline.enabled
• nextflow_config - Config variable found: trace.enabled
• nextflow_config - Config variable found: report.enabled
• nextflow_config - Config variable found: dag.enabled
• nextflow_config - Config variable found: process.cpus
• nextflow_config - Config variable found: process.memory
• nextflow_config - Config variable found: process.time
• nextflow_config - Config variable found: params.outdir
• nextflow_config - Config variable found: params.input
• nextflow_config - Config variable found: params.validationShowHiddenParams
• nextflow_config - Config variable found: params.validationSchemaIgnoreParams
• nextflow_config - Config variable found: manifest.mainScript
• nextflow_config - Config variable found: timeline.file
• nextflow_config - Config variable found: trace.file
• nextflow_config - Config variable found: report.file
• nextflow_config - Config variable found: dag.file
• nextflow_config - Config variable (correctly) not found: params.nf_required_version
• nextflow_config - Config variable (correctly) not found: params.container
• nextflow_config - Config variable (correctly) not found: params.singleEnd
• nextflow_config - Config variable (correctly) not found: params.igenomesIgnore
• nextflow_config - Config variable (correctly) not found: params.name
• nextflow_config - Config variable (correctly) not found: params.enable_conda
• nextflow_config - Config timeline.enabled had correct value: true
• nextflow_config - Config report.enabled had correct value: true
• nextflow_config - Config trace.enabled had correct value: true
• nextflow_config - Config dag.enabled had correct value: true
• nextflow_config - Config manifest.name began with nf-core/
• nextflow_config - Config variable manifest.homePage began with https://github.com/nf-core/
• nextflow_config - Config dag.file ended with .html
• nextflow_config - Config variable manifest.nextflowVersion started with >= or !>=
• nextflow_config - Config params.custom_config_version is set to master
• nextflow_config - Config params.custom_config_base is set to https://raw.githubusercontent.com/nf-core/configs/master
• nextflow_config - Lines for loading custom profiles found
• nextflow_config - nextflow.config contains configuration profile test
• nextflow_config - Config default value correct: params.mode= rd
• nextflow_config - Config default value correct: params.custom_config_version= master
• nextflow_config - Config default value correct: params.custom_config_base= https://raw.githubusercontent.com/nf-core/configs/master
• nextflow_config - Config default value correct: params.max_cpus= 16
• nextflow_config - Config default value correct: params.max_memory= 128.GB
• nextflow_config - Config default value correct: params.max_time= 240.h
• nextflow_config - Config default value correct: params.publish_dir_mode= copy
• nextflow_config - Config default value correct: params.max_multiqc_email_size= 25.MB
• nextflow_config - Config default value correct: params.validate_params= true
• files_unchanged - .gitattributes matches the template
• files_unchanged - .prettierrc.yml matches the template
• files_unchanged - CODE_OF_CONDUCT.md matches the template
• files_unchanged - LICENSE matches the template
• files_unchanged - .github/.dockstore.yml matches the template
• files_unchanged - .github/CONTRIBUTING.md matches the template
• files_unchanged - .github/ISSUE_TEMPLATE/bug_report.yml matches the template
• files_unchanged - .github/ISSUE_TEMPLATE/config.yml matches the template
• files_unchanged - .github/ISSUE_TEMPLATE/feature_request.yml matches the template
• files_unchanged - .github/workflows/branch.yml matches the template
• files_unchanged - .github/workflows/linting_comment.yml matches the template
• files_unchanged - .github/workflows/linting.yml matches the template
• files_unchanged - assets/email_template.html matches the template
• files_unchanged - assets/email_template.txt matches the template
• files_unchanged - assets/sendmail_template.txt matches the template
• files_unchanged - docs/images/nf-core-fastquorum_logo_light.png matches the template
• files_unchanged - docs/images/nf-core-fastquorum_logo_dark.png matches the template
• files_unchanged - docs/README.md matches the template
• actions_awstest - '.github/workflows/awstest.yml' is triggered correctly
• actions_awsfulltest - .github/workflows/awsfulltest.yml is triggered correctly
• actions_awsfulltest - .github/workflows/awsfulltest.yml does not use -profile test
• readme - README Nextflow minimum version badge matched config. Badge: 23.04.0, Config: 23.04.0
• pipeline_name_conventions - Name adheres to nf-core convention
• schema_lint - Schema lint passed
• schema_lint - Schema title + description lint passed
• schema_lint - Input mimetype lint passed: 'text/csv'
• schema_params - Schema matched params returned from nextflow config
• system_exit - No System.exit calls found
• actions_schema_validation - Workflow validation passed: branch.yml
• actions_schema_validation - Workflow validation passed: ci.yml
• actions_schema_validation - Workflow validation passed: awsfulltest.yml
• actions_schema_validation - Workflow validation passed: fix-linting.yml
• actions_schema_validation - Workflow validation passed: linting.yml
• actions_schema_validation - Workflow validation passed: download_pipeline.yml
• actions_schema_validation - Workflow validation passed: release-announcements.yml
• actions_schema_validation - Workflow validation passed: clean-up.yml
• actions_schema_validation - Workflow validation passed: awstest.yml
• actions_schema_validation - Workflow validation passed: linting_comment.yml
• merge_markers - No merge markers found in pipeline files
• modules_json - Only installed modules found in modules.json
• multiqc_config - assets/multiqc_config.yml found and not ignored.
• multiqc_config - assets/multiqc_config.yml contains report_section_order
• multiqc_config - assets/multiqc_config.yml contains export_plots
• multiqc_config - assets/multiqc_config.yml contains report_comment
• multiqc_config - assets/multiqc_config.yml follows the ordering scheme of the minimally required plugins.
• multiqc_config - assets/multiqc_config.yml contains a matching 'report_comment'.
• multiqc_config - assets/multiqc_config.yml contains 'export_plots: true'.
• modules_structure - modules directory structure is correct 'modules/nf-core/TOOL/SUBTOOL'
• base_config - conf/base.config found and not ignored.
• base_config - FASTQC found in conf/base.config and Nextflow scripts.
• base_config - MULTIQC found in conf/base.config and Nextflow scripts.
• modules_config - conf/modules.config found and not ignored.
• modules_config - BWA_INDEX found in conf/modules.config and Nextflow scripts.
• modules_config - SAMTOOLS_FAIDX found in conf/modules.config and Nextflow scripts.
• modules_config - SAMTOOLS_DICT found in conf/modules.config and Nextflow scripts.
• modules_config - FASTQC found in conf/modules.config and Nextflow scripts.
• modules_config - MULTIQC found in conf/modules.config and Nextflow scripts.
• nfcore_yml - Repository type in .nf-core.yml is valid: pipeline
• nfcore_yml - nf-core version in .nf-core.yml is set to the latest version: 2.14.1

Run details

• nf-core/tools version 2.14.1
• Run at 2024-06-05 14:57:22

[nh13]

This looks good to me when you're ready for review. Perhaps I can look into why it doesn't cache, so please keep the issue open.