DockerFile
Les Dockerfiles sont des fichiers qui permettent de construire une image Docker adaptée à nos besoins, étape par étape. Docker peut construire des images automatiquement en lisant les instructions d’un Dockerfile. Un Dockerfile est un document texte qui contient toutes les commandes qu’un utilisateur pourrait appeler sur la ligne de commande pour assembler une image. À l’aide de docker build, les utilisateurs peuvent créer une construction automatisée qui exécute successivement plusieurs instructions en ligne de commande.
Exemple de docker File ( source https://github.com/docker-library/redis/blob/master/Dockerfile-alpine.template)
FROM alpine:3.14
# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
RUN addgroup -S -g 1000 redis && adduser -S -G redis -u 999 redis
# alpine already has a gid 999, so we'll use the next id
RUN apk add --no-cache \
# grab su-exec for easy step-down from root
'su-exec>=0.2' \
# add tzdata for https://github.com/docker-library/redis/issues/138
tzdata
ENV REDIS_VERSION placeholder
ENV REDIS_DOWNLOAD_URL placeholder
ENV REDIS_DOWNLOAD_SHA placeholder
RUN set -eux; \
\
apk add --no-cache --virtual .build-deps \
coreutils \
dpkg-dev dpkg \
gcc \
linux-headers \
make \
musl-dev \
openssl-dev \
# install real "wget" to avoid:
# + wget -O redis.tar.gz https://download.redis.io/releases/redis-6.0.6.tar.gz
# Connecting to download.redis.io (45.60.121.1:80)
# wget: bad header line: XxhODalH: btu; path=/; Max-Age=900
wget \
; \
\
wget -O redis.tar.gz "$REDIS_DOWNLOAD_URL"; \
echo "$REDIS_DOWNLOAD_SHA *redis.tar.gz" | sha256sum -c -; \
mkdir -p /usr/src/redis; \
tar -xzf redis.tar.gz -C /usr/src/redis --strip-components=1; \
rm redis.tar.gz; \
\
# disable Redis protected mode [1] as it is unnecessary in context of Docker
# (ports are not automatically exposed when running inside Docker, but rather explicitly by specifying -p / -P)
# [1]: https://github.com/redis/redis/commit/edd4d555df57dc84265fdfb4ef59a4678832f6da
##<protected-mode-sed>##
grep -E '^ *createBoolConfig[(]"protected-mode",.*, *1 *,.*[)],$' /usr/src/redis/src/config.c; \
sed -ri 's!^( *createBoolConfig[(]"protected-mode",.*, *)1( *,.*[)],)$!\10\2!' /usr/src/redis/src/config.c; \
grep -E '^ *createBoolConfig[(]"protected-mode",.*, *0 *,.*[)],$' /usr/src/redis/src/config.c; \
##</protected-mode-sed>##
# for future reference, we modify this directly in the source instead of just supplying a default configuration flag because apparently "if you specify any argument to redis-server, [it assumes] you are going to specify everything"
# see also https://github.com/docker-library/redis/issues/4#issuecomment-50780840
# (more exactly, this makes sure the default behavior of "save on SIGTERM" stays functional by default)
\
# https://github.com/jemalloc/jemalloc/issues/467 -- we need to patch the "./configure" for the bundled jemalloc to match how Debian compiles, for compatibility
# (also, we do cross-builds, so we need to embed the appropriate "--build=xxx" values to that "./configure" invocation)
gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
extraJemallocConfigureFlags="--build=$gnuArch"; \
# https://salsa.debian.org/debian/jemalloc/-/blob/c0a88c37a551be7d12e4863435365c9a6a51525f/debian/rules#L8-23
dpkgArch="$(dpkg --print-architecture)"; \
case "${dpkgArch##*-}" in \
amd64 | i386 | x32) extraJemallocConfigureFlags="$extraJemallocConfigureFlags --with-lg-page=12" ;; \
*) extraJemallocConfigureFlags="$extraJemallocConfigureFlags --with-lg-page=16" ;; \
esac; \
extraJemallocConfigureFlags="$extraJemallocConfigureFlags --with-lg-hugepage=21"; \
grep -F 'cd jemalloc && ./configure ' /usr/src/redis/deps/Makefile; \
sed -ri 's!cd jemalloc && ./configure !&'"$extraJemallocConfigureFlags"' !' /usr/src/redis/deps/Makefile; \
grep -F "cd jemalloc && ./configure $extraJemallocConfigureFlags " /usr/src/redis/deps/Makefile; \
\
export BUILD_TLS=yes; \
make -C /usr/src/redis -j "$(nproc)" all; \
make -C /usr/src/redis install; \
\
# TODO https://github.com/redis/redis/pull/3494 (deduplicate "redis-server" copies)
serverMd5="$(md5sum /usr/local/bin/redis-server | cut -d' ' -f1)"; export serverMd5; \
find /usr/local/bin/redis* -maxdepth 0 \
-type f -not -name redis-server \
-exec sh -eux -c ' \
md5="$(md5sum "$1" | cut -d" " -f1)"; \
test "$md5" = "$serverMd5"; \
' -- '{}' ';' \
-exec ln -svfT 'redis-server' '{}' ';' \
; \
\
rm -r /usr/src/redis; \
\
runDeps="$( \
scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
| tr ',' '\n' \
| sort -u \
| awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
)"; \
apk add --no-network --virtual .redis-rundeps $runDeps; \
apk del --no-network .build-deps; \
\
redis-cli --version; \
redis-server --version
RUN mkdir /data && chown redis:redis /data
VOLUME /data
WORKDIR /data
COPY docker-entrypoint.sh /usr/local/bin/
ENTRYPOINT ["docker-entrypoint.sh"]
EXPOSE 6379
CMD ["redis-server"]