Propagate Base.active_project() from the "manager" process to the worker processes

Author: DilumAluthge

src/slurmmanager.jl

@@ -44,17 +44,48 @@ mutable struct SlurmManager <: ClusterManager
 end
 
 function launch(manager::SlurmManager, params::Dict, instances_arr::Array, c::Condition)
+    # Note: In the comments in this function, the phrase "manager Julia process" refers to the
+    # currently-active Julia process, i.e. the process that is running this Julia code.
     try
         exehome = params[:dir]
         exename = params[:exename]
         exeflags = params[:exeflags]
 
         # Pass the key-value pairs from `params[:env]` to the `srun` command:
         srun_cmd_without_env = `srun -D $exehome $exename $exeflags --worker`
+        the_user_specified_JULIA_PROJECT_in_params_env = false
         env2 = Dict{String,String}()
         for (name, value) in pairs(Dict{String,String}(params[:env]))
             env2[name] = value
+            if name == "JULIA_PROJECT"
+              the_user_specified_JULIA_PROJECT_in_params_env = true
+            end
         end
+        # If the user DID provide `JULIA_PROJECT` in `params[:env]`,
+        # then we respect that value and we do not override it.
+        #
+        # If the user did NOT provide `JULIA_PROJECT` in `params[:env]`,
+        # then we set `JULIA_PROJECT` to the value of `Base.active_project()`.
+        # https://github.com/kleinhenz/SlurmClusterManager.jl/issues/16
+        #
+        # Note that we use `Base.active_project()`.
+        # We intentionally do NOT use `Base.ACTIVE_PROJECT[]`.
+        # The reason is this: `Base.active_project()` is documented in the Julia manual.
+        # `Base.ACTIVE_PROJECT[]` is not documented in the Julia manual.
+        #
+        # Observe that there are three possible ways for a user to specify the active project
+        # for the "manager" process:
+        # 1. The user could have started the "manager" process with `JULIA_PROJECT=something julia`.
+        # 2. The user could have started the "manager" process with `julia --project` or `julia --project=something`.
+        # 3. The user could have started the "manager" process with `julia`, and then they used either
+        #    `Pkg.activate()` or `Base.set_active_project()` to activate a different project.
+        if the_user_specified_JULIA_PROJECT_in_params_env
+            @debug "Passing the user-provided value for JULIA_PROJECT to the worker processes" env2["JULIA_PROJECT"]
+        else
+            env2["JULIA_PROJECT"] = Base.active_project()
+            @debug "Passing JULIA_PROJECT=Base.active_project() for the worker processes" env2["JULIA_PROJECT"]
+        end
+        ###
         srun_cmd_with_env = addenv(srun_cmd_without_env, env2)
 
         # Pass cookie as stdin to srun; srun forwards stdin to process