Merge pull request #3174 from GEOS-ESM/feature/mathomp4/2845-esmf-env…

…-var

Fixes #2845. Allow ESMF_CONFIG_FILE to specify ESMF control file

CHANGELOG.md

@@ -9,10 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Added macro _RETURN(_SUCCESS) to fetch_data
+- Added macro `_RETURN(_SUCCESS)` to fetch_data
 - Allow update offsets of ±timestep in ExtData2G
 - Minor revision (and generalization) of grid-def for GSI purposes
-- Trajectory sampler: fix a bug when group_name does not exist in netCDF file and a bug that omitted the first time point
+- Add ability to use an `ESMF_CONFIG_FILE` environment variable to specify name of file to pass in pre-`ESMF_Initialize` options to ESMF (see [ESMF Docs](https://earthsystemmodeling.org/docs/release/latest/ESMF_refdoc/node4.html#SECTION04024000000000000000) for allowed flags.
 - Allow lat-lon grid factory to detect and use CF compliant lat-lon bounds in a file when making a grid
 - PFIO/Variable class, new procedures to retrieve string/reals/int attributes from a variable
 
@@ -50,6 +50,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fixed issue of some Baselibs builds appearing to support zstandard. This is not possible due to Baselibs building HDF5 and netCDF as static libraries
+- Trajectory sampler: fix a bug when group_name does not exist in netCDF file and a bug that omitted the first time point
 - Fixed a bug where the periodicity around the earth of the lat-lon grid was not being set properly when grid did not span from pole to pole
 
 ### Removed

gridcomps/Cap/MAPL_Cap.F90

@@ -274,9 +274,10 @@ subroutine run_model(this, comm, unusable, rc)
       integer :: rank, ierror
       integer :: status
       class(Logger), pointer :: lgr
-      logical :: file_exists
+      logical :: esmfConfigFileExists
       type (ESMF_VM) :: vm
-      character(len=:), allocatable :: esmfComm
+      character(len=:), allocatable :: esmfComm, esmfConfigFile
+      integer :: esmfConfigFileLen
 
       _UNUSED_DUMMY(unusable)
 
@@ -288,16 +289,41 @@ subroutine run_model(this, comm, unusable, rc)
       call MPI_COMM_RANK(comm, rank, status)
       _VERIFY(status)
 
+      ! We look to see if the user has set an environment variable for the
+      ! name of the ESMF configuration file. If they have, we use that. If not,
+      ! we use the default of "ESMF.rc" for backward compatibility
+
+      ! Step one: default to ESMF.rc
+
+      esmfConfigFile = 'ESMF.rc'
+      esmfConfigFileLen = len(esmfConfigFile)
+
+      ! Step two: get the length of the environment variable
+      call get_environment_variable('ESMF_CONFIG_FILE', length=esmfConfigFileLen, status=status)
+      ! Step three: if the environment variable exists, get the value of the environment variable
+      if (status == 0) then ! variable exists
+         ! We need to deallocate so we can reallocate
+         deallocate(esmfConfigFile)
+         allocate(character(len = esmfConfigFileLen) :: esmfConfigFile)
+         call get_environment_variable('ESMF_CONFIG_FILE', value=esmfConfigFile, status=status)
+         _VERIFY(status)
+      end if
+
       if (rank == 0) then
-         inquire(file='ESMF.rc', exist=file_exists)
+         inquire(file=esmfConfigFile, exist=esmfConfigFileExists)
       end if
-      call MPI_BCAST(file_exists, 1, MPI_LOGICAL, 0, comm, status)
+      call MPI_BCAST(esmfConfigFileExists, 1, MPI_LOGICAL, 0, comm, status)
+      _VERIFY(status)
+      call MPI_BCAST(esmfConfigFile, esmfConfigFileLen, MPI_CHARACTER, 0, comm, status)
       _VERIFY(status)
 
+      lgr => logging%get_logger('MAPL')
+
       ! If the file exists, we pass it into ESMF_Initialize, else, we
       ! use the one from the command line arguments
-      if (file_exists) then
-         call ESMF_Initialize (configFileName='ESMF.rc', mpiCommunicator=comm, vm=vm, _RC)
+      if (esmfConfigFileExists) then
+         call lgr%info("Using ESMF configuration file: %a", esmfConfigFile)
+         call ESMF_Initialize (configFileName=esmfConfigFile, mpiCommunicator=comm, vm=vm, _RC)
       else
          call ESMF_Initialize (logKindFlag=this%cap_options%esmf_logging_mode, mpiCommunicator=comm, vm=vm, _RC)
       end if
@@ -312,7 +338,6 @@ subroutine run_model(this, comm, unusable, rc)
       call ESMF_MeshSetMOAB(this%cap_options%with_esmf_moab, rc=status)
       _VERIFY(status)
 
-      lgr => logging%get_logger('MAPL')
       call lgr%info("Running with MOAB library for ESMF Mesh: %l1", this%cap_options%with_esmf_moab)
 
       call this%initialize_cap_gc(rc=status)