ci: use a build arg to set base image as alpine:3.7

Author: jumanjiman

Diff for: .gitignore

@@ -1,3 +1,4 @@
 *.swp
 *~
 **/hooktftp
+ci/vars

Diff for: README.md

@@ -197,9 +197,9 @@ Output from `ci/test` resembles:
     [RUN] docker_rm fixtures
 
     ===> Create data container in which to download test files.
-    [RUN] docker create --name downloads -v /home/user alpine:3.7 true
+    [RUN] docker create --name downloads -v /home/user ${BASE_IMAGE} true
     19d787a81fa8cc3d68fdd97f0d7fa85d2d3f95fadcd144e52f47aafda74fb763
-    [RUN] docker run --rm --volumes-from downloads alpine:3.7 chown -R 1000:1000 /home/user
+    [RUN] docker run --rm --volumes-from downloads ${BASE_IMAGE} chown -R 1000:1000 /home/user
 
     ===> Create data container for fixtures.
     [RUN] docker create --name fixtures hooktftp-fixtures true

Diff for: ci/build

@@ -1,19 +1,26 @@
 #!/bin/bash
 set -e
 
+cat >ci/vars <<EOF
+BASE_IMAGE='alpine:3.7'
+VCS_REF="$(git rev-parse --short HEAD)"
+TAG="$(date +%Y%m%dT%H%M)-git-\${VCS_REF}"
+EOF
+
 . ci/functions
+. ci/vars
 
 info "Build a tiny runtime image with hooktftp static binary."
 pushd src/alpine/builder
-run docker build --rm -t hooktftp-runtime .
+run docker build --rm --build-arg BASE_IMAGE="${BASE_IMAGE}" -t hooktftp-runtime .
 popd
 
 info "Build a fixtures images that we use to test."
 run docker build --rm -t hooktftp-fixtures fixtures/
 
 info "Build a tiny tftp client image that we use to test."
 pushd src/alpine/client
-run docker build --rm -t tftp .
+run docker build --rm --build-arg BASE_IMAGE="${BASE_IMAGE}" -t tftp .
 popd
 
 info "Show image sizes."

Diff for: ci/publish

@@ -2,11 +2,7 @@
 set -eEu
 set -o pipefail
 
-VCS_REF="$(git rev-parse --short HEAD)"
-readonly VCS_REF
-
-TAG="$(date +%Y%m%dT%H%M)-git-${VCS_REF}"
-readonly TAG
+. ci/vars
 
 # shellcheck disable=SC2154
 docker login -u "${user}" -p "${pass}"

Diff for: ci/test

@@ -4,6 +4,7 @@ set -o pipefail
 
 . ci/bootstrap
 . ci/functions
+. ci/vars
 . test/functions.bash
 
 info 'Run file checks.'
@@ -21,9 +22,9 @@ for cid in $cids; do
 done
 
 info "Create data container in which to download test files."
-run docker create --name downloads -v /home/user alpine:3.7 true
+run docker create --name downloads -v /home/user "${BASE_IMAGE}" true
 # Ensure the tftp client user has permissions on the volume.
-run docker run --rm --volumes-from downloads alpine:3.7 chown -R 1000:1000 /home/user
+run docker run --rm --volumes-from downloads "${BASE_IMAGE}" chown -R 1000:1000 /home/user
 
 info "Create data container for fixtures."
 run docker create --name fixtures hooktftp-fixtures true

Diff for: src/alpine/builder/Dockerfile

@@ -1,4 +1,5 @@
-FROM alpine:3.7 as builder
+ARG BASE_IMAGE
+FROM ${BASE_IMAGE} as builder
 
 RUN apk add --no-cache \
       busybox-extras \

Diff for: src/alpine/client/Dockerfile

@@ -1,4 +1,5 @@
-FROM alpine:3.7
+ARG BASE_IMAGE
+FROM ${BASE_IMAGE}
 
 # Install dependencies.
 RUN apk add --no-cache tftp-hpa

Diff for: test/functional_tests.bats

@@ -4,37 +4,37 @@ load functions
   run docker logs tftpd
   [[ ${output} =~ 'Dropped privileges' ]]
 
-  docker run --rm -it --pid container:tftpd --network container:tftpd alpine:3.7 ps -o pid,user,group,comm |
+  docker run --rm -it --pid container:tftpd --network container:tftpd "${BASE_IMAGE}" ps -o pid,user,group,comm |
   grep -E '1 1000     1000     hooktftp'
 }
 
 @test "downloads site/menu from fixtures" {
   tftp_get $ip site/menu
-  run docker run --rm --volumes-from downloads alpine:3.7 test -r /home/user/menu
+  run docker run --rm --volumes-from downloads "${BASE_IMAGE}" test -r /home/user/menu
   [ ${status} -eq 0 ]
 }
 
 @test "downloads pxelinux.0" {
   tftp_get $ip pxelinux.0
-  run docker run --rm --volumes-from downloads alpine:3.7 test -s /home/user/pxelinux.0
+  run docker run --rm --volumes-from downloads "${BASE_IMAGE}" test -s /home/user/pxelinux.0
   [ ${status} -eq 0 ]
 }
 
 @test "does not download a non-existent-file" {
   tftp_get $ip non-existent-file
-  run docker run --rm --volumes-from downloads alpine:3.7 test -s /home/user/non-existent-file
+  run docker run --rm --volumes-from downloads "${BASE_IMAGE}" test -s /home/user/non-existent-file
   [ ${status} -ne 0 ]
 }
 
 @test "downloads pxelinux.cfg/default" {
   tftp_get $ip pxelinux.cfg/default
-  run docker run --rm --volumes-from downloads alpine:3.7 test -s /home/user/default
+  run docker run --rm --volumes-from downloads "${BASE_IMAGE}" test -s /home/user/default
   [ ${status} -eq 0 ]
 }
 
 @test "downloads pxelinux.cfg/F1.msg" {
   tftp_get $ip pxelinux.cfg/F1.msg
-  run docker run --rm --volumes-from downloads alpine:3.7 test -s /home/user/F1.msg
+  run docker run --rm --volumes-from downloads "${BASE_IMAGE}" test -s /home/user/F1.msg
   [ ${status} -eq 0 ]
 }
 

Diff for: test/functions.bash

@@ -1,4 +1,7 @@
 # shellcheck shell=bash
+
+. ci/vars
+
 docker_rm() {
   cid=$1
   docker rm -f "${cid}" &>/dev/null || :