Activate environment in container file (#17316)

* Activate environment in container file

This PR will ensure that the container recipes will build the spack
environment by first activating the environment.

* Deactivate environment before environment collection

For Singularity, the environment must be deactivated before running the
command to collect the environment variables. This is because the
environment collection uses `spack env activate`.

share/spack/templates/container/Dockerfile

@@ -7,7 +7,7 @@ RUN mkdir {{ paths.environment }} \
 {{ manifest }} > {{ paths.environment }}/spack.yaml
 
 # Install the software, remove unecessary deps
-RUN cd {{ paths.environment }} && spack install && spack gc -y
+RUN cd {{ paths.environment }} && spack env activate . && spack install && spack gc -y
 {% if strip %}
 
 # Strip all the binaries

share/spack/templates/container/singularity.def

@@ -11,8 +11,10 @@ EOF
 
   # Install all the required software
   . /opt/spack/share/spack/setup-env.sh
+  spack env activate .
   spack install
   spack gc -y
+  spack env deactivate
   spack env activate --sh -d . >> {{ paths.environment }}/environment_modifications.sh
 {% if strip %}
 
@@ -87,4 +89,4 @@ Stage: final
 {% for label, value in labels.items() %}
   {{ label }} {{ value }}
 {% endfor %}
-{% endif %}
+{% endif %}