# Conda / Anaconda

Conda / Anaconda (https://conda.org) is a package manager that can be used to easily create tailored Python environments without having required C/... binaries of some packages installed on the local system. (i.e. conda will take care that required binaries are installed into the environment)

```{warning}
Due to certain license restrictions the usage of Anaconda at PSI is not allowed without obtaining a professional license from Anaconda.com!

However the usage of the command `conda` and/or of packages from conda-forge is still possible - see below ...
```

This guide explains how to install and configure conda in accordance to the Anaconda.com license terms.


## Installation
On a standard Linux system the conda package can be simply installed via a:

```
yum install conda
```

To instruct puppet to install the package you can have following hiera config:

```yaml
base::pkg_group::extra:
  - 'conda'

base::package_groups:
  - 'extra'
```

## Configuration

To overwrite the default configuration of conda (which would violate the license because packages would be installed from anaconda.org by default) following config file needs to be deployed in `/etc/conda/condarc.d/base.yml` (or similar):

```yaml
channels:
- conda-forge
- nodefaults

# Show channel URLs when displaying what is going to be downloaded
# and in 'conda list'. The default is False.
show_channel_urls: True
always_copy: true
```

To place the file via Puppet/Hiera you can have following configuration:

```yaml
files::files:
  /etc/conda/condarc.d/base.yml:
    content: | 
      channels:
      - conda-forge
      - nodefaults

      # Show channel URLs when displaying what is going to be downloaded
      # and in 'conda list'. The default is False.
      show_channel_urls: True
      always_copy: true
```


To be able to use the `conda` command a user needs to source the command into its current shell. This can be done like this:

```bash
source /opt/conda/etc/profile.d/conda.sh
```


Afterwards conda environments can be created in a license conformed way as documented at https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html


## Usage

More details on the usage of the `conda` command can be found here:
https://docs.conda.io/projects/conda/en/stable/user-guide/index.html


### Important Info
It seems that the `conda list <package>` command still uses the default channel. However `conda install` seem to respect the config above.

Probably related to this here:
https://stackoverflow.com/questions/67695893/how-do-i-completely-purge-and-disable-the-default-channel-in-anaconda-and-switch