Moving the RemoteWorker into tools/remote directory.

This is because I want to add another remote execution related tool, the remote_client, which will use the Remote Execution API to fetch blobs from a remote cache. I will use this tool as part of end-to-end tests for remote execution.

TESTED=remote integration tests, presubmit
RELNOTES: None
PiperOrigin-RevId: 177995895

1 files changed, 42 insertions, 0 deletions

diff --git a/src/tools/remote/README.md b/src/tools/remote/README.md
new file mode 100644
index 0000000000..d662790f4f
--- /dev/null
+++ b/src/tools/remote/README.md
@@ -0,0 +1,42 @@
+# Remote worker
+
+This program implements a remote execution worker that uses gRPC to accept work
+requests. It can work as a remote execution worker, a cache worker, or both.
+The simplest setup is as follows:
+
+- First build the worker and run it.
+
+        bazel build src/tools/remote:all
+        bazel-bin/src/tools/remote/worker \
+            --work_path=/tmp/test \
+            --listen_port=8080
+
+- Then you run Bazel pointing to the worker instance.
+
+        bazel build \
+            --spawn_strategy=remote --remote_cache=localhost:8080 \
+            --remote_executor=localhost:8080 src/tools/generate_workspace:all
+
+The above command will build generate_workspace with remote spawn strategy that
+uses the local worker as the distributed caching and execution backend.
+
+## Sandboxing
+
+If you run the worker on Linux, you can also enable sandboxing for increased hermeticity:
+
+        bazel-bin/src/tools/remote/worker \
+            --work_path=/tmp/test \
+            --listen_port=8080 \
+            --sandboxing \
+            --sandboxing_writable_path=/run/shm \
+            --sandboxing_tmpfs_dir=/tmp \
+            --sandboxing_block_network
+
+As you can see, the specific behavior of the sandbox can be tuned via the flags
+
+- --sandboxing_writable_path=<path> makes a path writable for running actions.
+- --sandboxing_tmpfs_dir=<path> will mount a fresh, empty tmpfs for each running action on a path.
+- --sandboxing_block_network will put each running action into its own network namespace that has
+  no network connectivity except for its own "localhost". Note that due to a Linux kernel issue this
+  might result in a loss of performance if you run many actions in parallel. For long running tests
+  it probably won't matter much, though.