Environments

Installing and configuring conda

Before you can create any e3 environments, you will need a working - and properly configured - conda environment. See Getting Started.

Creating e3 environments

An e3 environment is a virtual (conda) environment containing the EPICS module require. What else goes into the environment is dictated by you and your needs; you can create different environments for different IOCs on the same host (even with different EPICS base versions), or you can test an IOC against different module versions.

The following examples demonstrate different approaches to creating environments.

Let’s create one containing StreamDevice:

$ conda create -n e3-and-stream epics-base require stream

Show conda output

$ conda create -n e3-and-stream epics-base require stream
Channels:
 - ess-conda-local
 - conda-forge
Platform: linux-64
Collecting package metadata (repodata.json): done
Solving environment: done

## Package Plan ##

  environment location: /home/johndoe/miniforge3/envs/e3-and-stream

  added / updated specs:
    - epics-base
    - require
    - stream


The following NEW packages will be INSTALLED:

  asyn               ess-conda-local/linux-64::asyn-4.44.2-h4abd79c_0
  epics-base         conda-forge/linux-64::epics-base-7.0.9.0-h2f0025b_0
  pcre               conda-forge/linux-64::pcre-8.45-h9c3ff4c_0
  readline           conda-forge/linux-64::readline-8.2-h8228510_1
  require            ess-conda-local/linux-64::require-5.1.1-h6f9ad6c_0
  stream             ess-conda-local/linux-64::stream-2.8.25-hc22a8e2_0
  (... additional dependencies ...)

Proceed ([y]/n)? y

Preparing transaction: done
Verifying transaction: done
Executing transaction: done
#
# To activate this environment, use
#
#     $ conda activate e3-and-stream
#
# To deactivate an active environment, use
#
#     $ conda deactivate

Note how conda automatically resolves and installs asyn as a dependency of stream.

If you only need the pvAccess executables (e.g. pvget, pvput):

$ conda create --name=epics epics-base

Note

This creates a basic EPICS environment (not technically e3, as it lacks require) using conda-forge’s EPICS base package. Useful when you only need EPICS tools without the e3 module loading system.

If you have more specific needs, you can pin versions, e.g.:

$ conda create --name=my-special-e3-env epics-base=7.0.8.1 require asyn sequencer

You can also create an environment from an environment.yml file (a standard conda environment specification in YAML):

dependencies:
  - epics-base=7.0.9
  - require>5
  - modbus
  - s7plc

Then create the environment with:

$ conda env create --file=environment.yml

Using your e3 environments

Activate the environment:

$ conda activate e3-and-stream

You can now test that this worked by starting an IOC:

(e3-and-stream) $ iocsh

       ,----.     ,--. ,-----.  ,-----.           ,--.            ,--.,--.
 ,---. '.-.  |    |  |'  .-.  ''  .--./     ,---. |  ,---.  ,---. |  ||  |
| .-. :  .' <     |  ||  | |  ||  |        (  .-' |  .-.  || .-. :|  ||  |
\   --./'-'  |    |  |'  '-'  ''  '--'\    .-'  `)|  | |  |\   --.|  ||  |
 `----'`----'     `--' `-----'  `-----'    `----' `--' `--' `----'`--'`--'

Starting e3 IOC shell version 6.0.0
...
test >

Tip

Exit the IOC by typing exit at the console, or by pressing ^ d ( + d).

You can see which packages are installed in the environment by running:

$ conda list
# packages in environment at /home/johndoe/miniconda3/envs/e3-and-stream:
#
# Name                    Version                   Build  Channel
...
asyn                      4.44.2               h4abd79c_0    ess-conda-local
...
require                   5.1.1                h6f9ad6c_0    ess-conda-local
...
stream                    2.8.25               hc22a8e2_0    ess-conda-local
...

You can test any of these modules by running, for example:

(e3-and-stream) $ iocsh -r asyn  # -r is shorthand for the `require` call

Tip

The e3-and-stream environment will contain asyn (asyn) as that is a dependency of stream.