Add file extension for SnakeMake (github-linguist#3953)

* Add file extension for SnakeMake

Previously a file name was defined for [SnakeMake[(snakemake-wrappers.readthedocs.io): github-linguist#1834

Currently, the canonical extension is `smk` (see [this discussion](https://groups.google.com/forum/#!topic/Snakemake/segLE-RlV_s) with the author (@johanneskoester) of SnakeMake, and the [FAQ](http://snakemake.readthedocs.io/en/stable/project_info/faq.html#how-do-i-enable-syntax-highlighting-in-vim-for-snakefiles)).

* Adding two Snakemake (smk) example files

lib/linguist/languages.yml

@@ -4140,6 +4140,7 @@ Python:
   - ".pyt"
   - ".pyw"
   - ".rpy"
+  - ".smk"
   - ".spec"
   - ".tac"
   - ".wsgi"

samples/Python/snakemake-calling.smk

@@ -0,0 +1,68 @@
+# Source: https://raw.githubusercontent.com/snakemake-workflows/dna-seq-gatk-variant-calling/master/rules/calling.smk
+# Accessed: Jan 10 2020 by Nils Homer
+# License: MIT (https://github.com/snakemake-workflows/dna-seq-gatk-variant-calling/blob/master/LICENSE)
+
+if "restrict-regions" in config["processing"]:
+    rule compose_regions:
+        input:
+            config["processing"]["restrict-regions"]
+        output:
+            "called/{contig}.regions.bed"
+        conda:
+            "../envs/bedops.yaml"
+        shell:
+            "bedextract {wildcards.contig} {input} > {output}"
+
+
+rule call_variants:
+    input:
+        bam=get_sample_bams,
+        ref=config["ref"]["genome"],
+        known=config["ref"]["known-variants"],
+        regions="called/{contig}.regions.bed" if config["processing"].get("restrict-regions") else []
+    output:
+        gvcf=protected("called/{sample}.{contig}.g.vcf.gz")
+    log:
+        "logs/gatk/haplotypecaller/{sample}.{contig}.log"
+    params:
+        extra=get_call_variants_params
+    wrapper:
+        "0.27.1/bio/gatk/haplotypecaller"
+
+
+rule combine_calls:
+    input:
+        ref=config["ref"]["genome"],
+        gvcfs=expand("called/{sample}.{{contig}}.g.vcf.gz", sample=samples.index)
+    output:
+        gvcf="called/all.{contig}.g.vcf.gz"
+    log:
+        "logs/gatk/combinegvcfs.{contig}.log"
+    wrapper:
+        "0.27.1/bio/gatk/combinegvcfs"
+
+
+rule genotype_variants:
+    input:
+        ref=config["ref"]["genome"],
+        gvcf="called/all.{contig}.g.vcf.gz"
+    output:
+        vcf=temp("genotyped/all.{contig}.vcf.gz")
+    params:
+        extra=config["params"]["gatk"]["GenotypeGVCFs"]
+    log:
+        "logs/gatk/genotypegvcfs.{contig}.log"
+    wrapper:
+        "0.27.1/bio/gatk/genotypegvcfs"
+
+
+rule merge_variants:
+    input:
+        ref=get_fai(), # fai is needed to calculate aggregation over contigs below
+        vcfs=lambda w: expand("genotyped/all.{contig}.vcf.gz", contig=get_contigs()),
+    output:
+        vcf="genotyped/all.vcf.gz"
+    log:
+        "logs/picard/merge-genotyped.log"
+    wrapper:
+        "0.40.2/bio/picard/mergevcfs"

samples/Python/snakemake-mapping.smk

@@ -0,0 +1,90 @@
+# Source: https://raw.githubusercontent.com/snakemake-workflows/dna-seq-gatk-variant-calling/master/rules/mapping.smk
+# Accessed: Jan 10 2020 by Nils Homer
+# License: MIT (https://github.com/snakemake-workflows/dna-seq-gatk-variant-calling/blob/master/LICENSE)
+
+rule trim_reads_se:
+    input:
+        unpack(get_fastq)
+    output:
+        temp("trimmed/{sample}-{unit}.fastq.gz")
+    params:
+        extra="",
+        **config["params"]["trimmomatic"]["se"]
+    log:
+        "logs/trimmomatic/{sample}-{unit}.log"
+    wrapper:
+        "0.30.0/bio/trimmomatic/se"
+
+
+rule trim_reads_pe:
+    input:
+        unpack(get_fastq)
+    output:
+        r1=temp("trimmed/{sample}-{unit}.1.fastq.gz"),
+        r2=temp("trimmed/{sample}-{unit}.2.fastq.gz"),
+        r1_unpaired=temp("trimmed/{sample}-{unit}.1.unpaired.fastq.gz"),
+        r2_unpaired=temp("trimmed/{sample}-{unit}.2.unpaired.fastq.gz"),
+        trimlog="trimmed/{sample}-{unit}.trimlog.txt"
+    params:
+        extra=lambda w, output: "-trimlog {}".format(output.trimlog),
+        **config["params"]["trimmomatic"]["pe"]
+    log:
+        "logs/trimmomatic/{sample}-{unit}.log"
+    wrapper:
+        "0.30.0/bio/trimmomatic/pe"
+
+
+rule map_reads:
+    input:
+        reads=get_trimmed_reads
+    output:
+        temp("mapped/{sample}-{unit}.sorted.bam")
+    log:
+        "logs/bwa_mem/{sample}-{unit}.log"
+    params:
+        index=config["ref"]["genome"],
+        extra=get_read_group,
+        sort="samtools",
+        sort_order="coordinate"
+    threads: 8
+    wrapper:
+        "0.27.1/bio/bwa/mem"
+
+
+rule mark_duplicates:
+    input:
+        "mapped/{sample}-{unit}.sorted.bam"
+    output:
+        bam=temp("dedup/{sample}-{unit}.bam"),
+        metrics="qc/dedup/{sample}-{unit}.metrics.txt"
+    log:
+        "logs/picard/dedup/{sample}-{unit}.log"
+    params:
+        config["params"]["picard"]["MarkDuplicates"]
+    wrapper:
+        "0.26.1/bio/picard/markduplicates"
+
+
+rule recalibrate_base_qualities:
+    input:
+        bam=get_recal_input(),
+        bai=get_recal_input(bai=True),
+        ref=config["ref"]["genome"],
+        known=config["ref"]["known-variants"]
+    output:
+        bam=protected("recal/{sample}-{unit}.bam")
+    params:
+        extra=get_regions_param() + config["params"]["gatk"]["BaseRecalibrator"]
+    log:
+        "logs/gatk/bqsr/{sample}-{unit}.log"
+    wrapper:
+        "0.27.1/bio/gatk/baserecalibrator"
+
+
+rule samtools_index:
+    input:
+        "{prefix}.bam"
+    output:
+        "{prefix}.bam.bai"
+    wrapper:
+        "0.27.1/bio/samtools/index"