Cirrus: Fix gate image & false-positive exits

A number of scripts relating to tooling used and the gate container
image were not exiting upon errors as intended.  Coupled with
external service unavailability (i.e. downloading golangci-lint)
was observed to cause difficult to debug failures.

This change corrects the scripts inside/out of the gate container as
well as fixes many golang related path consistency problems vs other CI
jobs.  After this change, all jobs use consistent path names reducing
the number of special-case overrides needed.

Lastly, I also made a documentation-pass, updating/correcting as needed,
including documenting a likely local validation-failure mode, related to
`$EPOCH_TEST_COMMIT`.  This is dependent on the developers git
environment, so documentation is the only possible "fix".

Signed-off-by: Chris Evich <cevich@redhat.com>

4 files changed, 38 insertions, 23 deletions

diff --git a/contrib/cirrus/lib.sh b/contrib/cirrus/lib.sh
index 1ffe554e9..5895d84f4 100644
--- a/contrib/cirrus/lib.sh
+++ b/contrib/cirrus/lib.sh
@@ -68,9 +68,9 @@ export FEDORA_BASE_IMAGE="fedora-cloud-base-31-1-9-1578586410"
 export PRIOR_FEDORA_BASE_IMAGE="fedora-cloud-base-30-1-2-1578586410"
 export BUILT_IMAGE_SUFFIX="${BUILT_IMAGE_SUFFIX:--$CIRRUS_REPO_NAME-${CIRRUS_BUILD_ID}}"
 # IN_PODMAN container image
-IN_PODMAN_IMAGE="quay.io/libpod/in_podman:latest"
+IN_PODMAN_IMAGE="quay.io/libpod/in_podman:$DEST_BRANCH"
 # Image for uploading releases
-UPLDREL_IMAGE="quay.io/libpod/upldrel:latest"
+UPLDREL_IMAGE="quay.io/libpod/upldrel:master"
 
 # Avoid getting stuck waiting for user input
 export DEBIAN_FRONTEND="noninteractive"
diff --git a/contrib/gate/Dockerfile b/contrib/gate/Dockerfile
index 2a904a202..54bd2cbde 100644
--- a/contrib/gate/Dockerfile
+++ b/contrib/gate/Dockerfile
@@ -33,31 +33,36 @@ RUN dnf -y install \
       zip \
       && dnf clean all
 
-ENV GOPATH="/go" \
-    PATH="/go/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin" \
+ENV GOPATH="/var/tmp/go" \
+    GOBIN="/var/tmp/go/bin" \
+    PATH="/var/tmp/go/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin" \
     SRCPATH="/usr/src/libpod" \
-    GOSRC="/go/src/github.com/containers/libpod"
+    GOSRC="/var/tmp/go/src/github.com/containers/libpod"
 
-# Only needed for installing build-time dependencies
+# Only needed for installing build-time dependencies, then will be removed
 COPY / $GOSRC
 
-WORKDIR $GOSRC
-
 # Install dependencies
 RUN set -x && \
+    mkdir -p "$GOBIN" && \
+    mkdir -p /etc/cni/net.d && \
+    mkdir -p /etc/containers && \
     install -D -m 755 $GOSRC/contrib/gate/entrypoint.sh /usr/local/bin/ && \
-    python3 -m pip install pre-commit && \
-    rm -rf "$GOSRC"
+    python3 -m pip install pre-commit
 
 # Install cni config
-#RUN make install.cni
-RUN mkdir -p /etc/cni/net.d/
 COPY cni/87-podman-bridge.conflist /etc/cni/net.d/87-podman-bridge.conflist
-
 # Make sure we have some policy for pulling images
-RUN mkdir -p /etc/containers
 COPY test/policy.json /etc/containers/policy.json
 COPY test/redhat_sigstore.yaml /etc/containers/registries.d/registry.access.redhat.com.yaml
 
+WORKDIR "$GOSRC"
+RUN make install.tools && \
+    cd / && \
+    rm -rf "$GOSRC" && \
+    mkdir -p "$GOSRC"
 VOLUME ["/usr/src/libpod"]
+# This entrypoint will synchronize the above volume ($SRCPATH) to $GOSRC before
+# executing make.  This ensures the original source remains prestine and is never
+# modified by any lint/validation checks.
 ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
diff --git a/contrib/gate/README.md b/contrib/gate/README.md
index 709e6035f..fe1205dc5 100644
--- a/contrib/gate/README.md
+++ b/contrib/gate/README.md
@@ -1,4 +1,6 @@
 ![PODMAN logo](../../logo/podman-logo-source.svg)
 
-A standard container image for `gofmt` and lint-checking the libpod
-repository.  The [contributors guide contains the documentation for usage.](https://github.com/containers/libpod/blob/master/CONTRIBUTING.md#go-format-and-lint)
+A standard container image for lint-checking and validating changes to the libpod
+repository.  The
+[contributors guide contains the documentation for usage.](https://github.com/containers/libpod/blob/master/CONTRIBUTING.md#go-format-and-lint).  Note that this container image is also utilized
+in automation, see the file [.cirrus.yml](.cirrus.yml)
diff --git a/contrib/gate/entrypoint.sh b/contrib/gate/entrypoint.sh
index 0189cf7c5..ab6528e00 100755
--- a/contrib/gate/entrypoint.sh
+++ b/contrib/gate/entrypoint.sh
@@ -1,15 +1,23 @@
 #!/bin/bash
 
-[[ -n "$SRCPATH" ]] || \
-    ( echo "ERROR: \$SRCPATH must be non-empty" && exit 1 )
-[[ -n "$GOSRC" ]] || \
-    ( echo "ERROR: \$GOSRC must be non-empty" && exit 2 )
+set -e
+
+die() {
+    echo "${2:-FATAL ERROR (but no message given!)} (gate container entrypoint)"
+    exit ${1:-1}
+}
+
+[[ -n "$SRCPATH" ]] || die 1 "ERROR: \$SRCPATH must be non-empty"
+[[ -n "$GOPATH" ]] || die 2 "ERROR: \$GOPATH must be non-empty"
+[[ -n "$GOSRC" ]] || die 3 "ERROR: \$GOSRC must be non-empty"
 [[ -r "${SRCPATH}/contrib/gate/Dockerfile" ]] || \
-    ( echo "ERROR: Expecting libpod repository root at $SRCPATH" && exit 3 )
+    die 4 "ERROR: Expecting libpod repository root at $SRCPATH"
 
 # Working from a copy avoids needing to perturb the actual source files
-mkdir -p "$GOSRC"
+# if/when developers use gate container for local testing
+echo "Copying $SRCPATH to $GOSRC"
+mkdir -vp "$GOSRC"
 /usr/bin/rsync --recursive --links --quiet --safe-links \
                --perms --times --delete "${SRCPATH}/" "${GOSRC}/"
 cd "$GOSRC"
-make "$@"
+exec make "$@"