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+---
+title: "TP for computational biologists"
+author: Laurent Modolo [laurent.modolo@ens-lyon.fr](mailto:laurent.modolo@ens-lyon.fr)
+date: 20 Jun 2018
+output:
+pdf_document:
+toc: true
+toc_depth: 3
+    number_sections: true
+highlight: tango
+    latex_engine: xelatex
+---
+
+The goal of this practical is to learn how to *wrap* tools in [Docker](https://www.docker.com/what-docker) or [Environment Module](http://www.ens-lyon.fr/PSMN/doku.php?id=documentation:tools:modules) to make them available to nextflow on a personal computer or at the [PSMN](http://www.ens-lyon.fr/PSMN/doku.php).
+
+Here we assume that you followed the [TP for experimental biologists](./TP_experimental_biologists.md), and that you know the basics on [Docker containers](https://www.docker.com/what-container) and [Environment Module](http://www.ens-lyon.fr/PSMN/doku.php?id=documentation:tools:modules) usage. We also are going to assume that you know how to build and use a nextflow pipeline from the template [pipelines/nextflow](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow).
+
+For the practical you can either work with the WebIDE of Gitlab, or locally as described in [git : the basis formation](https://gitlab.biologie.ens-lyon.fr/formations/git_basis).
+
+# Docker
+
+To run a tools within a [Docker container](https://www.docker.com/what-container) you need to write a `Dockerfile`.
+
+`Dockerfile` are found in the [pipelines/nextflow](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow) project under `src/docker_modules/`. Each `Dockerfile` are paired with a `docker_init.sh` file like following example for `Kallisto` version `0.43.1`:
+
+```sh
+$ ls -l src/docker_modules/Kallisto/0.43.1/
+total 16K                                                                        
+drwxr-xr-x 2 laurent users 4.0K Jun  5 19:06 ./                                  
+drwxr-xr-x 3 laurent users 4.0K Jun  6 09:49 ../                                 
+-rw-r--r-- 1 laurent users  587 Jun  5 19:06 Dockerfile                          
+-rwxr-xr-x 1 laurent users   79 Jun  5 19:06 docker_init.sh*                     
+```
+
+## `docker_init.sh`
+The `docker_init.sh` is a simple sh script with the executable right (`chmod +x`).By executing this script, the user creates the [Docker container](https://www.docker.com/what-container) for the tools in a specific version. You can check the `docker_init.sh` file of any implemented tools as a template. Remember that the name of the [container](https://www.docker.com/what-container) must be in lower case.
+
+## `Dockerfile`
+
+The recipe to wrap your tool in a [Docker container](https://www.docker.com/what-container) is written in a `Dockerfile` file.
+
+For `Kallisto` version `0.44.0` the header of the `Dockerfile` is :
+
+```Docker
+FROM ubuntu:18.04
+MAINTAINER Laurent Modolo
+
+ENV KALLISTO_VERSION=0.44.0
+```
+
+This means that we initialize the [container](https://www.docker.com/what-container) from a bare installation of Ubuntu 18.04. You can check the ubuntu  available versions [here](https://hub.docker.com/_/ubuntu/) or others operating systems like [debian](https://hub.docker.com/_/debian/) or [worst](https://hub.docker.com/r/microsoft/windowsservercore/).
+
+Then we declare the *maintainer* of the container. Before declaring a environment variable for the container named `KALLISTO_VERSION` which contains the version of the tools wrapped. This means that this bash variable will be declared within the [container](https://www.docker.com/what-container).
+
+You should always declare a variable `TOOLSNAME_VERSION` that contains the version number of commit number of the tools you wrap. Therefore in simple case you just have to modify this line to create a new `Dockerfile` for another version of the tool.
+
+The following of the `Dockerfile` is a succession of `bash` commands executed as the **root** user within the container.
+When you build your `Dockerfile`, instead of launching many time the `docker_init.sh` script you can connect to a base container in interactive mode to launch tests your commands.
+
+```sh
+docker run -it ubuntu:18.04 bash
+KALLISTO_VERSION=0.44.0
+```
+
+Each `RUN` block is run sequentially by `Docker`. If there is an error or modifications in a `RUN` block, only this block and the following `RUN` will be executed.
+
+You can learn more about the building of Docker containers [here](https://docs.docker.com/engine/reference/builder/#usage).
+
+# SGE
+
+To run easily tools on the PSMN, you need to build your own [Environment Module](http://www.ens-lyon.fr/PSMN/doku.php?id=documentation:tools:modules).
+
+You can read the Contributing guide of the [PMSN/modules](https://gitlab.biologie.ens-lyon.fr/PSMN/modules) [here](https://gitlab.biologie.ens-lyon.fr/PSMN/modules/blob/master/CONTRIBUTING.md)
+
+# Nextflow
+
+The last step to wrap your tool, is to make it available in nextflow. For this you need to create at least 4 files, like the following for Kallisto version `0.44.0`:
+
+```sh
+ls -lR src/nf_modules/Kallisto
+src/nf_modules/Kallisto/:
+total 12
+-rw-r--r-- 1 laurent users  866 Jun 18 17:13 kallisto.config
+-rw-r--r-- 1 laurent users 2711 Jun 18 17:13 kallisto.nf
+drwxr-xr-x 2 laurent users 4096 Jun 18 17:14 tests/
+
+src/nf_modules/Kallisto/tests:
+total 16
+-rw-r--r-- 1 laurent users  551 Jun 18 17:14 index.nf
+-rw-r--r-- 1 laurent users  901 Jun 18 17:14 mapping_paired.nf
+-rw-r--r-- 1 laurent users 1037 Jun 18 17:14 mapping_single.nf
+-rwxr-xr-x 1 laurent users  627 Jun 18 17:14 tests.sh*
+```
+
+The `Kallisto.config` file contains intruction for two profiles : `sge` and `docker`.
+The `Kallisto.nf` file contains nextflow processes to use `Kallisto`.
+
+The `tests/tests.sh` script, contains a serie of calls nextflow on the other `.nf` files of the `tests/` folder. Those tests correspond to execution of the processes present in the `Kallisto.nf` file on the [LBMC/tiny_dataset](https://gitlab.biologie.ens-lyon.fr/LBMC/tiny_dataset) dataset. You can read the *Running the tests* section of the [README.md](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow/blob/master/README.md).
+