Backport of env2yaml arm64 Docker build context fixes

This commit contains fixes made to the main 8.x branch to generate
arm64 and amd64 env2yaml binaries, copy them into the build context
and correctly identify the correct binary in the Dockerfile to
include in the Docker image.

A clean backport was not available due to the change in format of
Dockerfile template from j2 to erb in elastic#15142

This contains fixes from elastic#15980 and elastic#16053.

docker/Makefile

@@ -64,7 +64,9 @@ build-from-local-ubi8-artifacts: venv dockerfile env2yaml
 	  (docker kill $(HTTPD); false);
 	-docker kill $(HTTPD)
 
-COPY_FILES = $(ARTIFACTS_DIR)/docker/config/pipelines.yml $(ARTIFACTS_DIR)/docker/config/logstash-oss.yml $(ARTIFACTS_DIR)/docker/config/logstash-full.yml $(ARTIFACTS_DIR)/docker/config/log4j2.properties $(ARTIFACTS_DIR)/docker/pipeline/default.conf $(ARTIFACTS_DIR)/docker/bin/docker-entrypoint $(ARTIFACTS_DIR)/docker/env2yaml/env2yaml
+COPY_FILES = $(ARTIFACTS_DIR)/docker/config/pipelines.yml $(ARTIFACTS_DIR)/docker/config/logstash-oss.yml $(ARTIFACTS_DIR)/docker/config/logstash-full.yml $(ARTIFACTS_DIR)/docker/config/log4j2.properties $(ARTIFACTS_DIR)/docker/pipeline/default.conf $(ARTIFACTS_DIR)/docker/bin/docker-entrypoint
+COPY_FILES += $(ARTIFACTS_DIR)/docker/env2yaml/env2yaml-arm64
+COPY_FILES += $(ARTIFACTS_DIR)/docker/env2yaml/env2yaml-amd64
 
 $(ARTIFACTS_DIR)/docker/config/pipelines.yml: data/logstash/config/pipelines.yml
 $(ARTIFACTS_DIR)/docker/config/logstash-oss.yml: data/logstash/config/logstash-oss.yml
@@ -73,6 +75,8 @@ $(ARTIFACTS_DIR)/docker/config/log4j2.properties: data/logstash/config/log4j2.pr
 $(ARTIFACTS_DIR)/docker/pipeline/default.conf: data/logstash/pipeline/default.conf
 $(ARTIFACTS_DIR)/docker/bin/docker-entrypoint: data/logstash/bin/docker-entrypoint
 $(ARTIFACTS_DIR)/docker/env2yaml/env2yaml: data/logstash/env2yaml/env2yaml
+$(ARTIFACTS_DIR)/docker/env2yaml/env2yaml-arm64: data/logstash/env2yaml/env2yaml-arm64
+$(ARTIFACTS_DIR)/docker/env2yaml/env2yaml-amd64: data/logstash/env2yaml/env2yaml-amd64
 
 $(ARTIFACTS_DIR)/docker/%:
 	cp -f $< $@
@@ -198,8 +202,12 @@ venv: requirements.txt
 env2yaml:
 	docker run --rm \
 	  -v "$(PWD)/data/logstash/env2yaml:/usr/src/env2yaml" \
-		-w /usr/src/env2yaml golang:1 go build
-
+		-e GOARCH=arm64 -e GOOS=linux \
+		-w /usr/src/env2yaml golang:1 go build -o /usr/src/env2yaml/env2yaml-arm64
+	docker run --rm \
+	  -v "$(PWD)/data/logstash/env2yaml:/usr/src/env2yaml" \
+		-e GOARCH=amd64 -e GOOS=linux \
+		-w /usr/src/env2yaml golang:1 go build -o /usr/src/env2yaml/env2yaml-amd64
 # Generate the Dockerfiles from Jinja2 templates.
 dockerfile: venv templates/Dockerfile.j2
 	$(foreach FLAVOR, $(IMAGE_FLAVORS), \

docker/templates/Dockerfile.j2

@@ -147,7 +147,25 @@ ADD pipeline/default.conf pipeline/logstash.conf
 RUN chown --recursive logstash:root config/ pipeline/
 # Ensure Logstash gets the correct locale by default.
 ENV LANG={{ locale }} LC_ALL={{ locale }}
-ADD env2yaml/env2yaml /usr/local/bin/
+
+# Copy over the appropriate env2yaml artifact
+COPY env2yaml/env2yaml-amd64 env2yaml/
+COPY env2yaml/env2yaml-arm64 env2yaml/
+
+RUN env2yamlarch="$(arch)"; \
+  case "${env2yamlarch}" in \
+    'x86_64') \
+      env2yamlarch=amd64; \
+      ;; \
+    'aarch64') \
+      env2yamlarch=arm64; \
+      ;; \
+    *) echo >&2 "error: unsupported architecture '$env2yamlarch'"; exit 1 ;; \
+  esac; \
+  cp env2yaml/env2yaml-${env2yamlarch} /usr/local/bin/env2yaml; \
+  rm -rf env2yaml
+
+
 # Place the startup wrapper script.
 ADD bin/docker-entrypoint /usr/local/bin/
 {% else -%}
@@ -156,6 +174,7 @@ COPY scripts/config/logstash.yml config/logstash.yml
 COPY scripts/config/log4j2.properties config/
 COPY scripts/pipeline/default.conf pipeline/logstash.conf
 RUN chown --recursive logstash:root config/ pipeline/
+
 # Place the startup wrapper script.
 COPY scripts/bin/docker-entrypoint /usr/local/bin/
 {% endif -%}