renamed MET_FORCE_TAG variable in testing workflow to SET_MET_IMAGE t…

…o be more clear of its purpose and added documentation to describe how to set the MET image to use previous stable releases or development versions in the tests

.github/jobs/docker_setup.sh

@@ -43,11 +43,11 @@ elif [ "${EXTERNAL_TRIGGER}" == "true" ]; then
     MET_TAG=${MET_TAG}-lite
 fi
 
-# if MET_FORCE_TAG variable is set and not empty, use that version instead
+# if SET_MET_IMAGE variable is set and not empty, use that version instead
 # format is <REPO>:<TAG> where the repo used is dtcenter/<REPO> and
 # the tag used is <TAG>, e.g. met:11.1.0 uses dtcenter/met:11.1.0
-if [ ! -z "$MET_FORCE_TAG" ]; then
-    force_info=(${MET_FORCE_TAG//:/ })
+if [ ! -z "$SET_MET_IMAGE" ]; then
+    force_info=(${SET_MET_IMAGE//:/ })
     MET_DOCKER_REPO=${force_info[0]}
     MET_TAG=${force_info[1]}
 fi

.github/workflows/testing.yml

@@ -99,7 +99,7 @@ jobs:
           DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
           DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
           EXTERNAL_TRIGGER: ${{ needs.job_control.outputs.external_trigger }}
-          MET_FORCE_TAG: met-dev:feature_2597_disk_space
+          SET_MET_IMAGE: met-dev:feature_2597_disk_space
 
   update_data_volumes:
     name: Docker Setup - Update Data Volumes

docs/Contributors_Guide/continuous_integration.rst

@@ -470,7 +470,7 @@ Create/Update METplus Docker Image
           env:
             DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
             DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
-            #MET_FORCE_TAG: 10.0.0
+            #SET_MET_IMAGE: met:10.0.0
 
 This job calls the **docker_setup.sh** script.
 This script builds a METplus Docker image and pushes it to DockerHub.
@@ -496,15 +496,33 @@ development testing. If testing is done on a stable release, then the
 corresponding MET stable release will be used. However, there may be an
 instance where a change in MET breaks something in another METplus component,
 i.e. METplotpy or METviewer, until a corresponding change is made to that
-component. If this occurs then some of the METplus use cases may break. To
-allow the tests to run successfully in the meantime, an option was added to
-force the version of the MET tag that is used to build the METplus Docker image
-that is used for testing. In the **testing.yml** workflow file,
-there is a commented variable called
-MET_FORCE_TAG that can be uncommented and set to force the version of MET to
-use. This variable is found in the **get_image** job under the **env** section
+component. If this occurs then some of the METplus use cases may break.
+
+Another situation that may require a different MET Docker image is if there
+are changes in a MET feature or bugfix branch that are needed to test changes
+in METplus.
+
+To allow the tests to run successfully in these cases, an option was added to
+force a specific MET Docker image to be used to build the METplus Docker image
+that is used for testing.
+
+In the **testing.yml** workflow file, there is a commented variable called
+SET_MET_IMAGE that can be uncommented and set the MET Docker image to use.
+This variable is found in the **get_image** job under the **env** section
 for the step named "Get METplus Image."
 
+The format of the value is <REPO>:<TAG>
+where the DockerHub repo used is dtcenter/<REPO> and the tag used is <TAG>.
+
+Stable releases of MET are found in the dtcenter/met DockerHub repo and
+are named using the X.Y.Z version of the release,
+so setting **SET_MET_IMAGE=met:11.1.0** will use dtcenter/met:11.1.0.
+
+Development versions of MET are found in the dtcenter/met-dev DockerHub
+repo and are named using the branch name,
+so setting **SET_MET_IMAGE=met-dev:feature_XYZ_info** will use
+dtcenter/met-dev:feature_XYZ_info.
+
 
 .. _cg-ci-update-data-volumes: