feat: shrink support for fluxion

This changeset exposes the remove_subgraph function,
which we can call a shrink. It does not account for
(I do not think) handling jobs properly, but should
be a reasonable start to testing or debugging.

Signed-off-by: vsoch <[email protected]>

.devcontainer/Dockerfile

@@ -20,7 +20,7 @@ RUN wget https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz  && tar -xvf go${G
 ENV PATH=$PATH:/usr/local/go/bin:/home/vscode/go/bin
 
 # Testing grow/shrink from custom branch
-RUN git clone -b debug-resource-error-messages https://github.com/researchapps/flux-sched /opt/flux-sched
+RUN git clone -b add-shrink https://github.com/researchapps/flux-sched /opt/flux-sched
 # RUN git clone https://github.com/flux-framework/flux-sched /opt/flux-sched
 
 # We also need to rebuild into the system install

.github/workflows/main.yaml

@@ -38,7 +38,14 @@ jobs:
 
     # TODO: we should consider distributing the header files with the release builds
     - name: flux-sched build
-      run: git clone https://github.com/flux-framework/flux-sched /opt/flux-sched    
+      run: git clone -b add-shrink https://github.com/researchapps/flux-sched /opt/flux-sched    
+    - name: flux-sched compile
+      run: |
+        cd /opt/flux-sched
+        cmake -B build
+        make -C build
+        make -C build install
+        cd -
     - name: Build
       run: LIB_PREFIX=${{ matrix.test[1] }} make build
     - name: Test Binary

cmd/test/test.go

@@ -173,6 +173,25 @@ func main() {
 		log.Fatalf("Error in ReapiClient MatchSatisfy - asking for 4 nodes should now succeed: %v\n", err)
 	}
 
+	// Shrink (remove subgraph) for node2
+	fmt.Println("🥕 Asking to Shrink from 4 to 3 Nodes")
+	err = cli.Shrink("/tiny0/rack0/node2")
+	if err != nil {
+		log.Fatalf("Error in ReapiClient Shrink: %s %s\n", err, cli.GetErrMsg())
+	}
+	fmt.Printf("Shrink request return value: %v\n", err)
+
+	fmt.Println("Asking to MatchSatisfy 4 nodes (again, not possible)")
+	sat, overhead, err = cli.MatchSatisfy(growJobspec)
+	checkErrors(cli)
+	if err != nil {
+		log.Fatalf("Error in ReapiClient MatchSatisfy: %v\n", err)
+	}
+	printSatOutput(sat, err)
+	if sat {
+		log.Fatalf("Error in ReapiClient MatchSatisfy - asking for 4 nodes with only 3 should fail: %v\n", err)
+	}
+
 }
 
 func printOutput(reserved bool, allocated string, at int64, jobid uint64, err error) {

pkg/fluxcli/reapi_cli.go

@@ -220,14 +220,14 @@ func (cli *ReapiClient) UpdateAllocate(jobid int, r string) (at int64, overhead
 	return at, overhead, r_out, err
 }
 
-// Update the resource state with R.
+// Update the resource state with R (grow).
 //
 //	\param h   Opaque handle. How it is used is an implementation
-//		       detail. However, when it is used within a Flux's
+//		   detail. However, when it is used within a Flux's
 //	           service module, it is expected to be a pointer
 //			           to a flux_t object.
-//	\param R_subgraph R String
-//	\return          0 on success; -1 on error.
+//	\param     R_subgraph R String
+//	\return    0 on success; -1 on error.
 //	int reapi_cli_grow (reapi_cli_ctx_t *ctx, const char *R_subgraph);
 func (cli *ReapiClient) Grow(rSubgraph string) (err error) {
 	var resources = C.CString(rSubgraph)
@@ -237,6 +237,23 @@ func (cli *ReapiClient) Grow(rSubgraph string) (err error) {
 	return retvalToError(fluxerr, "issue resource api client grow")
 }
 
+// Update the resource state (shrink) with R_node_path.
+//
+//	\param h            Opaque handle. How it is used is an implementation
+//		            detail. However, when it is used within a Flux's
+//	                    service module, it is expected to be a pointer
+//			           to a flux_t object.
+//	\param R_node_path R String to prune down
+//	\return          0 on success; -1 on error.
+//	int reapi_cli_shrink (reapi_cli_ctx_t *ctx, const char *R_node_path);
+func (cli *ReapiClient) Shrink(rNodePath string) (err error) {
+	var nodePath = C.CString(rNodePath)
+	defer C.free(unsafe.Pointer(nodePath))
+
+	fluxerr := (int)(C.reapi_cli_shrink((*C.struct_reapi_cli_ctx)(cli.ctx), nodePath))
+	return retvalToError(fluxerr, "issue resource api client shrink")
+}
+
 // Cancel cancels the allocation or reservation corresponding to jobid.
 //
 //	\param jobid     jobid of the uint64_t type.