Set HOME environment variable for runs-as user

Summary:
Fixes build issues around home permissions by setting `HOME` to the
unprivileged user's home directory once the "privileges dropped" build
phase has been reached.

Test Plan: Run `go test ./...`.

Reviewers: thcipriani, mobrovac, hashar, Jrbranaa, mmodell, #release-engineering-team

Reviewed By: mobrovac

Tags: #release-engineering-team

Differential Revision: https://phabricator.wikimedia.org/D686

2 files changed, 11 insertions, 0 deletions

diff --git a/docker/compiler.go b/docker/compiler.go
index 0a16362..f398164 100644
--- a/docker/compiler.go
+++ b/docker/compiler.go
@@ -96,6 +96,8 @@ func CompileInstruction(buffer *bytes.Buffer, instruction build.Instruction) {
 		Writeln(buffer, append([]string{"RUN "}, instruction.Arguments...)...)
 	case build.Copy:
 		Writeln(buffer, "COPY [\"", instruction.Arguments[0], "\", \"", instruction.Arguments[1], "\"]")
+	case build.Env:
+		Writeln(buffer, "ENV ", strings.Join(instruction.Arguments, " "))
 	}
 }
 
diff --git a/docker/compiler_test.go b/docker/compiler_test.go
index c6fec1b..7f6ee87 100644
--- a/docker/compiler_test.go
+++ b/docker/compiler_test.go
@@ -52,3 +52,12 @@ func TestCompileInstructionCopy(t *testing.T) {
 
 	assert.Equal(t, "COPY [\"foo\", \"bar\"]\n", buffer.String())
 }
+
+func TestCompileInstructionEnv(t *testing.T) {
+	buffer := new(bytes.Buffer)
+	instruction := build.Instruction{build.Env, []string{"foo=bar", "baz=qux"}}
+
+	docker.CompileInstruction(buffer, instruction)
+
+	assert.Equal(t, "ENV foo=bar baz=qux\n", buffer.String())
+}