[recipes] Compute DM flags in gen_tasks

Change-Id: I3d82d78161373ec0536cbe6df196c753547501a8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/274200
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>

Author: erock2112

infra/bots/gen_tasks_logic/gen_tasks_logic.go

@@ -13,6 +13,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/exec"
 	"path"
 	"path/filepath"
 	"regexp"
@@ -1420,8 +1421,34 @@ func (b *builder) test(name string, parts map[string]string, compileTaskName str
 		extraProps[k] = v
 	}
 	iid := b.internalHardwareLabel(parts)
+	iidStr := ""
 	if iid != nil {
-		extraProps["internal_hardware_label"] = strconv.Itoa(*iid)
+		iidStr = strconv.Itoa(*iid)
+	}
+	if recipe == "test" {
+		partsJson, err := json.Marshal(parts)
+		if err != nil {
+			glog.Fatal(err)
+		}
+		dmFlagsScript := filepath.Join(CheckoutRoot(), "infra", "bots", "recipe_modules", "vars", "resources", "dm_flags.py")
+		out, err := exec.Command(
+			"python", dmFlagsScript,
+			"--bot", name,
+			"--parts", string(partsJson),
+			"--task_id", specs.PLACEHOLDER_TASK_ID,
+			"--revision", specs.PLACEHOLDER_REVISION,
+			"--issue", specs.PLACEHOLDER_ISSUE,
+			"--patchset", specs.PLACEHOLDER_PATCHSET,
+			"--patch_storage", specs.PLACEHOLDER_PATCH_STORAGE,
+			"--buildbucket_build_id", specs.PLACEHOLDER_BUILDBUCKET_BUILD_ID,
+			"--swarming_bot_id", "${SWARMING_BOT_ID}",
+			"--swarming_task_id", "${SWARMING_TASK_ID}",
+			"--internal_hardware_label", iidStr,
+		).CombinedOutput()
+		if err != nil {
+			glog.Fatal(err)
+		}
+		extraProps["dm_flags"] = strings.TrimSpace(string(out))
 	}
 	task := b.kitchenTask(name, recipe, isolate, "", b.swarmDimensions(parts), extraProps, OUTPUT_TEST)
 	task.CipdPackages = append(task.CipdPackages, pkgs...)

infra/bots/recipe_modules/vars/resources/dm_flags.py

@@ -859,4 +859,4 @@ def remove_from_args(arg):
     swarming_task_id=args.swarming_task_id,
     internal_hardware_label=args.internal_hardware_label,
   )
-  print json.dumps(f)
+  print json.dumps(f, separators=(',', ':'))