Merge ~ubuntu-docker-images/ubuntu-docker-images/+git/telegraf:1.17-21.04-fix-missing-manifest into ~ubuntu-docker-images/ubuntu-docker-images/+git/telegraf:1.17-21.04

[Athos Ribeiro]

Do not use pipes in RUN commands

Using pipes without properly handling the earlier commands may conceal errors even when "set -e" is used.

Since setting the pipefail option may not be an alternative (we are using dash), we should refactor commands using pipes to avoid concealing errors.

This should avoid releasing images with missing bits.

[Sergio Durigan Junior (sergiodj)]

Thank you for the MP and for catching this problem, Athos. Needless to say, I totally agree with the rationale here. It crossed my mind that we'd be creating new files under /tmp, but since we're doing this in the first stage (build), that's alright.

On a side note: as I told you during standup, I think we can do better in our unit tests and make sure that the generated manifest is not empty. I will submit a PR shortly to address this.

BTW, we will need to update the 20.04 Dockerfile as well.

review: Approve

[Sergio Durigan Junior (sergiodj)]

Sorry, I've just noticed that you filed an MP for the 20.04 image. Please ignore the last sentence.

diff --git a/Dockerfile b/Dockerfile
index 2f858b1..3bcd73f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,8 @@ FROM ubuntu:hirsute AS manifest-builder
 WORKDIR /src/telegraf
 
 RUN set -eux; \
-	grep '^deb ' /etc/apt/sources.list | sed 's/^deb/deb-src/' >> /etc/apt/sources.list; \
+	grep '^deb ' /etc/apt/sources.list > /tmp/bin-repos-sources.list; \
+	sed 's/^deb/deb-src/' /tmp/bin-repos-sources.list >> /etc/apt/sources.list; \
 	DEBIAN_FRONTEND=noninteractive apt-get update; \
 	DEBIAN_FRONTEND=noninteractive apt-get full-upgrade -y; \
 	DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
@@ -16,8 +17,10 @@ RUN set -eux; \
 #
 # https://github.com/golang/go/issues/35224
 # https://bugs.launchpad.net/docker.io/+bug/1916296
-	go list -mod=mod -m all | tail -n +2 > /src/telegraf/telegraf-mods.txt; \
-	/src/telegraf/utils/golang-manifest-builder.py /src/telegraf/telegraf-mods.txt | tee /src/telegraf/manifest-upstream.txt
+	go list -mod=mod -m all > /tmp/telegraf-go-list.output; \
+	tail -n +2 /tmp/telegraf-go-list.output > /src/telegraf/telegraf-mods.txt; \
+	/src/telegraf/utils/golang-manifest-builder.py /src/telegraf/telegraf-mods.txt > /src/telegraf/manifest-upstream.txt; \
+	cat /src/telegraf/manifest-upstream.txt
 
 FROM ubuntu:hirsute