From 17eff1c5004ad1d84d2369414fc02d1e20c7da0c Mon Sep 17 00:00:00 2001
From: Nicolas Le Cam <niko.lecam@gmail.com>
Date: Sun, 9 Jun 2019 00:35:17 +0200
Subject: [PATCH 1/2] allow running commands inside the container

use the same technique as the one in the official Node.js image
---
 Dockerfile           |  5 ++++-
 README.adoc          | 33 ++-------------------------------
 docker-entrypoint.sh |  8 ++++++++
 3 files changed, 14 insertions(+), 32 deletions(-)
 create mode 100755 docker-entrypoint.sh

diff --git a/Dockerfile b/Dockerfile
index dae4540..e431257 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,4 +15,7 @@ RUN yarn global add --ignore-optional --silent @antora/cli@latest @antora/site-g
 
 WORKDIR /antora
 
-ENTRYPOINT [ "antora" ]
+COPY docker-entrypoint.sh /usr/local/bin/
+ENTRYPOINT ["docker-entrypoint.sh"]
+
+CMD ["antora"]
diff --git a/README.adoc b/README.adoc
index de2b41a..e3a7403 100644
--- a/README.adoc
+++ b/README.adoc
@@ -65,41 +65,12 @@ You can fix this problem by setting the cache dir explicitly when running Antora
    antora/antora --stacktrace --cache-dir=./.cache site.yml
 ====
 
-If you want to shell into the container, set the `--entrypoint` option as follows:
+If you want to shell into the container, use the following command:
 
- $ docker run --entrypoint ash --privileged -v `pwd`:/antora --rm -it antora/antora
+ $ docker run --privileged -v `pwd`:/antora --rm -it antora/antora ash
 
 This command allows you to use the `antora` command inside the running container (but still generate files to the local filesystem).
 
-[#gitlab-ci-image]
-=== Use the image in GitLab CI
-
-If you attempt to use this image as the base image in GitLab CI, you'll likely encounter the following error message (just after the `Skipping Git submodules setup` line in the log):
-
- error: unknown option `-c'
-
-This happens because this image defines the `antora` command as the default entrypoint rather than a shell command.
-In order to use this image as the base image in GitLab CI, you'll need to override the entrypoint to be a shell command as GitLab CI expects.
-
-To override the entrypoint in a way that's compatible with GitLab CI, define the image in `.gitlab-ci.yml` as follows:
-
-[source,yaml]
-----
-image: 
-  name: antora/antora
-  entrypoint: [/bin/sh, -c]
-----
-
-Now you'll be able to invoke the `antora` command from a script clause in `.gitlab-ci.yml` as follows:
-
-[source,yaml] 
-----
-  script:
-  - antora site.yml
-----
-
-This is similar to how we shelled into the container by passing the `--entrypoint` option in the previous section.
-
 [#extend-image]
 === Use as a Base Image
 
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
new file mode 100755
index 0000000..b670d13
--- /dev/null
+++ b/docker-entrypoint.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+  set -- antora "$@"
+fi
+
+exec "$@"
-- 
GitLab


From 8db95f069937acb2087837fc64a574c819d43169 Mon Sep 17 00:00:00 2001
From: Dan Allen <dan.j.allen@gmail.com>
Date: Sun, 25 Aug 2019 17:03:47 -0600
Subject: [PATCH 2/2] revise entrypoint change

* add comments to entrypoint script
* use more concise checks to determine if command was specified
* restore GitLab CI section in README, but clarify the images works without modification
* revise comments in README
---
 Dockerfile           |  1 +
 README.adoc          | 31 +++++++++++++++++++++++++++----
 docker-entrypoint.sh |  5 ++++-
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index e431257..1ebf0e3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,6 +16,7 @@ RUN yarn global add --ignore-optional --silent @antora/cli@latest @antora/site-g
 WORKDIR /antora
 
 COPY docker-entrypoint.sh /usr/local/bin/
+
 ENTRYPOINT ["docker-entrypoint.sh"]
 
 CMD ["antora"]
diff --git a/README.adoc b/README.adoc
index e3a7403..35e783b 100644
--- a/README.adoc
+++ b/README.adoc
@@ -1,4 +1,4 @@
-= Docker Image for Antora 
+= Docker Image for Antora
 :uri-antora: https://antora.org
 :uri-asciidoctor: https://asciidoctor.org
 :uri-license: https://www.mozilla.org/en-US/MPL/2.0/
@@ -32,7 +32,8 @@ If you want to help improve this image, you should learn how to <<build-image,bu
 
 This image is intended to be used as a command in a box.
 You can use this image as a replacement for the `antora` command to execute a playbook.
-The benefit is that you don't actually to install Antora itself.
+(The arguments that follow the name of the image are assumed to either be arguments to the `antora` command or a local command).
+The benefit is that you don't have to install Antora itself.
 
 To demonstrate how to use this image, we'll be using the https://gitlab.com/antora/demo/demo-site[Antora demo site].
 Start by cloning the playbook repository for the demo site, then switch to the newly created folder:
@@ -67,9 +68,31 @@ You can fix this problem by setting the cache dir explicitly when running Antora
 
 If you want to shell into the container, use the following command:
 
- $ docker run --privileged -v `pwd`:/antora --rm -it antora/antora ash
+ $ docker run --privileged -v `pwd`:/antora --rm -it antora/antora sh
 
-This command allows you to use the `antora` command inside the running container (but still generate files to the local filesystem).
+This command allows you to run the `antora` command from a prompt inside the running container (but will generate files to the local filesystem).
+
+In fact, if the first argument following the image name is a local command, the container will execute that command instead of `antora`.
+
+[#gitlab-ci-image]
+=== Use the image in GitLab CI
+
+Thanks to the custom entrypoint script ([.path]_docker-entrypoint.sh_), this image will work on GitLab CI without having to specify the entrypoint.
+Simply reference the image name at the top of the [.path]_.gitlab-ci.yml_ file, as shown here:
+
+[source,yaml]
+----
+image:
+  name: antora/antora
+----
+
+By using this image, you can invoke the `antora` command from a script clause in [.path]_.gitlab-ci.yml_ as follows:
+
+[source,yaml]
+----
+  script:
+  - antora site.yml
+----
 
 [#extend-image]
 === Use as a Base Image
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index b670d13..1f46341 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -1,7 +1,10 @@
 #!/bin/sh
+
+# abort script if a command fails
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# prepend antora if command is not detected
+if [ $# -eq 0 ] || [ "${1:0:1}" == '-' ] || [ -z `command -v "$1" || echo -n` ]; then
   set -- antora "$@"
 fi
 
-- 
GitLab