Conda.md

+Overview of [conda](https://conda.io/) and [conda-forge](https://conda-forge.org/) distribution of CDS packages.
+
+The plan is to make all CDS workstation software available via conda, through the same "conda-forge" channel that all LSCSoft software is available from:
+
+ * https://lscsoft.docs.ligo.org/conda/
+ * https://lscsoft.docs.ligo.org/conda/packaging/
+
+The list of packages that define the "official" lscsoft set is defined here:
+
+ * https://git.ligo.org/computing/conda
+
+
+## CDS packaging status
+
+Existing feedstocks:
+
+ * https://github.com/conda-forge/guardian-feedstock
+ * https://github.com/conda-forge/gpstime-feedstock
+ * https://github.com/conda-forge/ndscope-feedstock
+
+Missing packages:
+
+ * DTT
+ * cdsutils
+ * python3-ezca
+
+Other needed stuff:
+
+ * git/gitk (both in `git` package)
+ * ?
+
+
+### EPICS
+
+EPICS has some issues that need to be resolved.  There are two epics "base" packages: `epics-base` which is 3.15.6, and `epicscorelibs` which is based on "EPICS 7":
+
+ * https://github.com/conda-forge/epics-base-feedstock
+ * https://github.com/conda-forge/epicscorelibs-feedstock
+ * https://github.com/conda-forge/pyepics-feedstock
+ * https://github.com/conda-forge/pcaspy-feedstock
+
+Unfortunately, pyepics and pcaspy (both dependencies of guardian) are using the different versions:
+
+ * https://github.com/conda-forge/pyepics-feedstock/issues/19
+
+Extensions:
+
+ * MEDM (requires epics-extensions)
+ * StripTool (requires epics-extensions)
+
+`epics-base` installs the ca binaries in a non-standard path that is not linked in by default (`$EPICS_BASE/bin/linux-x86_64`):
+
+ * https://github.com/conda-forge/epics-base-feedstock/issues/5
+
+## CI builds
+
+We would like all CDS software building conda packages via gitlab CI.  Here's an example of how it's done for the lalsuite project:
+
+ * https://git.ligo.org/lscsoft/lalsuite/blob/master/.gitlab-ci.yml#L191
+ * https://git.ligo.org/lscsoft/lalsuite/blob/master/.gitlab-ci.yml#L317
+
+## Repo mirroring
+
+CDS will likely want to mirror conda-forge for site distribution:
+
+ * https://wiki.ligo.org/Computing/Conda#Self_45hosting
+
+## local builds
+
+It's possible to build and "distribute" conda packages locally.
+
+ * https://lscsoft.docs.ligo.org/conda/packaging/#testing-package-builds
+
+This is demonstrated in the lalsuite CI above.  There are two relevant environment variables:
+
+ * `CONDA_BLD_PATH`: package build dir
+ * `CONDA_PKGS_DIRS`: conda install dir
+
+With these defined, the following local build/install should work:
+```shell
+$ git clone https://github.com/conda-forge/lal-feedstock.git
+$ cd lal-feedstock
+$ conda build recipe
+```
+Then:
+```shell
+$ conda install --use-local lal
+```
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