Update NGINX process parser to handle worker processes that look like master processes

Author: dhurley

api/grpc/mpi/v1/command_grpc.pb.go

@@ -46,7 +46,7 @@ func NewNginxProcessParser() *NginxProcessParser {
 // cognitive complexity of 16 because of the if statements in the for loop
 // don't think can be avoided due to the need for continue
 //
-//nolint:revive // cognitive complexity of 20 because of the if statements in the for loop
+//nolint:revive,gocognit // cognitive complexity of 20 because of the if statements in the for loop
 func (npp *NginxProcessParser) Parse(ctx context.Context, processes []*nginxprocess.Process) map[string]*mpi.Instance {
 	slog.DebugContext(ctx, "Parsing NGINX processes", "number_of_processes", len(processes))
 
@@ -102,6 +102,15 @@ func (npp *NginxProcessParser) Parse(ctx context.Context, processes []*nginxproc
 
 		// check if proc is a master process, process is not a worker but could be cache manager etc
 		if proc.IsMaster() {
+			// sometimes a master process can have another master as parent
+			// which means that it is actually a worker process and not a master process
+			if masterProcess, ok := processesByPID[proc.PPID]; ok {
+				workers[masterProcess.PID] = append(workers[masterProcess.PID],
+					&mpi.InstanceChild{ProcessId: proc.PID})
+
+				continue
+			}
+
 			nginxInfo, err := npp.info(ctx, proc)
 			if err != nil {
 				slog.DebugContext(ctx, "Unable to get NGINX info", "pid", proc.PID, "error", err)

api/grpc/mpi/v1/files_grpc.pb.go

@@ -228,6 +228,17 @@ func TestNginxProcessParser_Parse_Processes(t *testing.T) {
 		instancesList[1].GetInstanceMeta().GetInstanceId(): instancesList[1],
 	}
 
+	process6 := protos.NginxOssInstance(nil)
+	process6.GetInstanceRuntime().InstanceChildren = []*mpi.InstanceChild{
+		{ProcessId: 567},
+		{ProcessId: 789},
+		{ProcessId: 5678},
+	}
+
+	instancesTest6 := map[string]*mpi.Instance{
+		process6.GetInstanceMeta().GetInstanceId(): process6,
+	}
+
 	tests := []struct {
 		expected  map[string]*mpi.Instance
 		name      string
@@ -368,6 +379,40 @@ func TestNginxProcessParser_Parse_Processes(t *testing.T) {
 			},
 			expected: make(map[string]*mpi.Instance),
 		},
+		{
+			name: "Test 6: 1 master process each with 2 workers and 1 master process",
+			processes: []*nginxprocess.Process{
+				{
+					PID:  1234,
+					PPID: 1,
+					Name: "nginx",
+					Cmd:  "nginx: master process /usr/local/opt/nginx/bin/nginx -g daemon off;",
+					Exe:  exePath,
+				},
+				{
+					PID:  789,
+					PPID: 1234,
+					Name: "nginx",
+					Cmd:  "nginx: worker process",
+					Exe:  exePath,
+				},
+				{
+					PID:  567,
+					PPID: 1234,
+					Name: "nginx",
+					Cmd:  "nginx: worker process",
+					Exe:  exePath,
+				},
+				{
+					PID:  5678,
+					PPID: 1234,
+					Name: "nginx",
+					Cmd:  "nginx: master process /usr/local/opt/nginx/bin/nginx -g daemon off;",
+					Exe:  exePath,
+				},
+			},
+			expected: instancesTest6,
+		},
 	}
 
 	for _, test := range tests {