Settings
EVL installation resides (usually) in
/opt/evl
To initiate EVL for current user, run
/opt/evl/bin/evl --init
which add an .evlrc file into your $HOME folder and add sourcing it into $HOME/.bashrc.
Then one can check, add or modify some settings in .evlrc, for example variable EVL_ENV.
These settings are top level settings for given user. (Later there are project.sh files in each project, to set project-wide variables.)
After that EVL is ready to use. Good to start is to create new project with some sample data, jobs and workflows:
evl project sample my_first_sample
Compiler
Mappings are compiled either by GCC or Clang. It depends on environment variable EVL_COMPILER,
these two values are possible:
EVL_COMPILER=gcc EVL_COMPILER=clang
If this variable is not set, then on Linux systems is GCC by default, and on Windows and Mac it is Clang.
GCC must be at least in the version 7.4 and Clang at least 6.0.
When Clang would be the option, one can replace gcc/c++ packages by clang above in installation instructions.
Project
EVL project is a directory with EVL jobs, workflow, data structure definitions, mappings, etc. Each project is intended for a group of jobs and workflows which are grouped somehow from the business point of view. So completely unrelated processings, which share nothing, would be good to place in separate projects.
project.sh
Each project has project.sh file inside. This file contains project-wide settings.
If the project is created by evl project new or by evl project sample command,
then project.sh would contain a good set of variables to start with.
Path to log and tmp folders are handled by environment variables:
EVL_PROJECT_LOG_DIR¶path to folder where log files are stored,
EVL_PROJECT_TMP_DIR¶path to folder where temporary files are stored.
By default are these variables set to:
EVL_PROJECT_LOG_DIR="$EVL_LOG_PATH/<project_name>" EVL_PROJECT_TMP_DIR="$EVL_TMP_PATH/<project_name>"
These values can be override in project.sh file.
Project directory structure
In each project directory, there would be these files and folders:
.comp_bin/contains subdirectories of compiled components of each job (one subfolder equals to one evl file).
doc/generated and/or custom documentation of the project.
evc/*.evcEVL custom component definition files.
evd/*.evdEVL data definition files.
evs/*.evsEVL job structure files (job definition itself, sometimes called a graph of ETL process).
evm/*.evmEVL mapping files for components
Aggreg,JoinandMap.ews/*.ewsEVL workflow structure files.
run/*.evlfiles, called by
evl runcommand, which specify the variables for the job structure, i.e. it contains parameters of the job described by evs file.workflow/*.ewfEVL workflow parameter files for ews files.
project.shThis file is interpreted as
bashshell script at the beginning of each job in the project. Usually contains all project wide variables.