chore(sg): sg bazel uses remote cache by default (unless in CI) (#62245)

.aspect/bazelrc/remote_cache_for_local.bazelrc

@@ -0,0 +1,23 @@
+# Only download remote outputs of top level targets to the local machine.
+# Docs: https://bazel.build/reference/command-line-reference#flag--remote_download_toplevel
+build --remote_download_toplevel
+
+# Upload locally executed action results to the remote cache.
+# Docs: https://bazel.build/reference/command-line-reference#flag--remote_upload_local_results
+build --remote_upload_local_results
+
+# Fall back to standalone local execution strategy if remote execution fails. If the grpc remote
+# cache connection fails, it will fail the build, add this so it falls back to the local cache.
+# Docs: https://bazel.build/reference/command-line-reference#flag--remote_local_fallback
+build --remote_local_fallback
+
+# These likely perform faster locally than the overhead of pulling/pushing from/to the remote cache,
+# as well as being able to reduce how much we push to the cache
+common --modify_execution_info=CopyDirectory=+no-remote,CopyToDirectory=+no-remote,CopyFile=+no-remote
+
+common --credential_helper=storage.googleapis.com=%workspace%/dev/remote_cache_local_env.sh
+common --remote_cache=https://storage.googleapis.com/local_bazel_remote_cache
+
+# If true, remote cache I/O will happen in the background instead of taking place as the part of a spawn.
+# Docs: https://bazel.build/reference/command-line-reference#flag--experimental_remote_cache_async
+common  --experimental_remote_cache_async

dev/remote_cache_local_env.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+GCP_PROJECT="sourcegraph-local-dev"
+
+function emit_headers() {
+  echo "{\"headers\":{\"Authorization\":[\"Bearer ${1}\"]}}"
+}
+
+emit_headers "$(gcloud --project ${GCP_PROJECT} auth print-access-token)"
+exit 0

dev/sg/sg_bazel.go

@@ -51,13 +51,47 @@ var bazelCommand = &cli.Command{
 	HideHelpCommand: true,
 	Usage:           "Proxies the bazel CLI with custom commands for local dev convenience",
 	Category:        category.Dev,
-	Action: func(ctx *cli.Context) error {
-		if slices.Equal(ctx.Args().Slice(), []string{"help"}) || slices.Equal(ctx.Args().Slice(), []string{"--help"}) || slices.Equal(ctx.Args().Slice(), []string{"-h"}) {
+	Action: func(cctx *cli.Context) error {
+		if slices.Equal(cctx.Args().Slice(), []string{"help"}) || slices.Equal(cctx.Args().Slice(), []string{"--help"}) || slices.Equal(cctx.Args().Slice(), []string{"-h"}) {
 			fmt.Println("Additional commands from sg:")
 			fmt.Println("  configure           Wrappers around some commands to generate various files required by Bazel")
+			fmt.Println("Additional flags from sg:")
+			fmt.Println("  --disable-remote-cache           Disable use of the remote cache for local env.")
 		}
 
-		cmd := exec.CommandContext(ctx.Context, "bazel", ctx.Args().Slice()...)
+		// Walk the args, looking for our custom flag to disable the remote cache.
+		// If we find it, we take not of it, but do not append it to the final args
+		// that will be passed to the bazel command. Everything else is passed as-is.
+		var disableRemoteCache bool
+		args := make([]string, 0, len(cctx.Args().Slice()))
+		for _, arg := range cctx.Args().Slice() {
+			switch arg {
+			case "--disable-remote-cache":
+				disableRemoteCache = true
+			case "--disable-remote-cache=true":
+				disableRemoteCache = true
+			case "--disable-remote-cache=false":
+				disableRemoteCache = false
+			default:
+				args = append(args, arg)
+			}
+		}
+
+		// If we end up running `sg bazel` in CI, we don't want to use the remote cache for local environment,
+		// so we force disable the flag explicilty.
+		if os.Getenv("CI") == "true" || os.Getenv("BUILDKITE") == "true" {
+			disableRemoteCache = true
+		}
+
+		if !disableRemoteCache {
+			newArgs := make([]string, 0, len(args)+1)
+			// Bazelrc flags must be added before the actual command (build, run, test ...)
+			newArgs = append(newArgs, "--bazelrc=.aspect/bazelrc/remote_cache_for_local.bazelrc")
+			newArgs = append(newArgs, args...)
+			args = newArgs
+		}
+
+		cmd := exec.CommandContext(cctx.Context, "bazel", args...)
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
 		cmd.Stdin = os.Stdin