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/*
 * Copyright (c) 2016. The University of Texas Southwestern Medical Center
 *
 *   This file is part of the BioHPC Workflow Platform
 *
 * Example ChIP-Seq analysis script, demonstrating the BioHPC Workflow Platform
 *
 * @authors
 * David Trudgian <David.Trudgian@UTSouthwestern.edu>
 *
 */

// Path to an input file, or a pattern for multiple inputs
// Note - $baseDir is the location of this workflow file main.nf
params.fastq = "$baseDir/../test_data/*.fastq"
// Path to the BWA Index (.fa file) that we are using for the analysis
params.index = "/project/apps_database/iGenomes/Homo_sapiens/UCSC/hg19/Sequence/BWAIndex/genome.fa"

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// First, get the list of fastqs. When multiple files are selected on the web
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// a glob pattern will be passed in
fastqs = Channel.fromPath( params.fastq )
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// Now find the path to the BWA index directory
index_path = file(params.index).parent
// And get the name of the actual index inside that directory
index_name = file(params.index).name

// bwa_aln
// Run BWA aln on a fastq file, to produce sai output
//
// Input   - fastq_file is taken from the fastq channel
//         - BWA index at $index_path/$index_name
//
// Output  - pair of fastq & generated sai file into the alignments channel 
process bwa_aln {

    // Tell Nextflow we will use 32 cpus here for BWA
    cpus 32

    input:
    file fastq_file from fastqs
     
    output:
    set file(fastq_file), file("${fastq_file.name}.sai") into alignments

 
    """
    module load BWA/0.7.5
    bwa aln $index_path/$index_name -t 32 $fastq_file > "${fastq_file.name}.sai"
    """
}

// bwa_aln
// Run bwa samse to produce sam.gz from an sai alignment
//
// Input   - pair of fastq file and corresponding sai file, from alignments channel
//
// Output  - .sam.gz into the samfiles channel, and baseDir/output
process bwa_samse {

    // bwa samse will use a single cpu core
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    cpus 1
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    // Publish the outputs we create here into the workflow output directory
    publishDir "$baseDir/output", mode: 'copy'
    
    input:
    set file(fastq_file), file(sai_file) from alignments 

    output:
    file "${fastq_file.name}.sam.gz" into samfiles
 
    """
    module load BWA/0.7.5
    bwa samse -r "@RG\tID:${fastq_file.name}\tLB:${fastq_file.name}\tSM:${fastq_file.name}\tPL:ILLUMINA" $index_path/$index_name\
    $sai_file $fastq_file | gzip > "${fastq_file.name}.sam.gz"
    """
}

// sam2bam
// Convert SAM file to BAM file, sorting by co-ordinate and indexing
//
// Input   - a sam file, (possibly gzipped) from the samfile channel
//
// Output  - .sam.gz into the samfiles channel, and baseDir/output
process sam2bam {


    // Tell Nextflow picard will only use one cpu.
    // We are allocating 32GB to java though, so tell
    // Nextflow so it can assign the task appropriately.
    cpus 1
    memory '32GB'

    // Publish the outputs we create here into the workflow output directory
    publishDir "$baseDir/output", mode: 'copy'
    
    input:
    file sam_file from samfiles

    output:
    file "${sam_file.name}.bam" into bamfiles
 
    """
    module add picard/1.127
    java -Xmx32G -jar \$PICARD/picard.jar SortSam \
    INPUT="${sam_file}" \
    OUTPUT="${sam_file.name}.bam" \
    SORT_ORDER=coordinate \
    VALIDATION_STRINGENCY=LENIENT \
    CREATE_INDEX=true
    """
}

// macs
// Peak calling on a bam using MACS 1.4
//
// Input   - a bam file, from the bamfiles channel
//
// Output  - various wig and bed into baseDir/output 
process macs14 {

    // Publish the outputs we create here into the workflow output directory
    publishDir "$baseDir/output", mode: 'copy'
    
    input:
    file bam_file from bamfiles

    output:
    file "${bam_file}_bwa_nomodel_MACS_wiggle"
    file "${bam_file}_bwa_nomodel_peaks.bed"
    file "${bam_file}_bwa_nomodel_peaks.xls"
    file "${bam_file}_bwa_nomodel_summits.bed"
 
    """
    module add macs/1.4.2
    macs14 -t ${bam_file} \
      --name ${bam_file}_bwa_nomodel \
      --nomodel \
      --wig \
      --single-profile \
      -f BAM
    """
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}