From a6325cca51143bcd319ac58dda7ba45082fcad9e Mon Sep 17 00:00:00 2001
From: Adin Scannell <adin@scannell.ca>
Date: Mon, 25 May 2020 18:21:03 -0700
Subject: [PATCH] Ensure docker group exists in the container.

The --groups command will fail if the group is not defined in
/etc/groups, even though it is specified by GID.

By coincidence, the group happens to be there for many installations of
Ubuntu 18.04 (which uses 999 for the Docker group), but it is strangely
absent in others (which use 130).

Fixes #2765
---
 tools/bazel.mk | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/bazel.mk b/tools/bazel.mk
index 7cb6e393b..b774c8fab 100644
--- a/tools/bazel.mk
+++ b/tools/bazel.mk
@@ -21,7 +21,8 @@ BRANCH_NAME := $(shell (git branch --show-current 2>/dev/null || \
 
 # Bazel container configuration (see below).
 USER ?= gvisor
-DOCKER_NAME ?= gvisor-bazel-$(shell readlink -m $(CURDIR) | md5sum | cut -c1-8)
+HASH ?= $(shell readlink -m $(CURDIR) | md5sum | cut -c1-8)
+DOCKER_NAME ?= gvisor-bazel-$(HASH)
 DOCKER_PRIVILEGED ?= --privileged
 BAZEL_CACHE := $(shell readlink -m ~/.cache/bazel/)
 GCLOUD_CONFIG := $(shell readlink -m ~/.config/gcloud/)
@@ -40,6 +41,7 @@ FULL_DOCKER_RUN_OPTIONS += -v "$(DOCKER_SOCKET):$(DOCKER_SOCKET)"
 DOCKER_GROUP := $(shell stat -c '%g' $(DOCKER_SOCKET))
 ifneq ($(GID),$(DOCKER_GROUP))
 USERADD_OPTIONS += --groups $(DOCKER_GROUP)
+GROUPADD_DOCKER += groupadd --gid $(DOCKER_GROUP) --non-unique docker-$(HASH) &&
 FULL_DOCKER_RUN_OPTIONS += --group-add $(DOCKER_GROUP)
 endif
 endif
@@ -71,10 +73,12 @@ bazel-server-start: load-default ## Starts the bazel server.
 		$(FULL_DOCKER_RUN_OPTIONS) \
 		gvisor.dev/images/default \
 		sh -c "groupadd --gid $(GID) --non-unique $(USER) && \
+		       $(GROUPADD_DOCKER) \
 		       useradd --uid $(UID) --non-unique --no-create-home --gid $(GID) $(USERADD_OPTIONS) -d $(HOME) $(USER) && \
 	               bazel version && \
 		       exec tail --pid=\$$(bazel info server_pid) -f /dev/null"
-	@while :; do if docker logs $(DOCKER_NAME) 2>/dev/null | grep "Build label:" >/dev/null; then break; fi; sleep 1; done
+	@while :; do if docker logs $(DOCKER_NAME) 2>/dev/null | grep "Build label:" >/dev/null; then break; fi; \
+		if ! docker ps | grep $(DOCKER_NAME); then exit 1; else sleep 1; fi; done
 .PHONY: bazel-server-start
 
 bazel-shutdown: ## Shuts down a running bazel server.