Auto-generate README (for version number)

CMakeLists.txt

@@ -19,6 +19,11 @@ configure_file (
 	"${PROJECT_BINARY_DIR}/tiniConfig.h"
 )
 
+configure_file (
+	"${PROJECT_SOURCE_DIR}/README.md.in"
+	"${PROJECT_SOURCE_DIR}/README.md"
+)
+
 include_directories ("${PROJECT_BINARY_DIR}")
 
 add_executable (tini tini.c)

README.md

@@ -19,7 +19,7 @@ to manually invoke Tini:
 
     # Add Tini
     ENV TINI_VERSION v0.3.2
-    ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
+    ADD https://github.com/krallin/tini/releases/download//tini /tini
     RUN chmod +x /tini
     ENTRYPOINT ["/tini", "--"]
 

README.md.in

@@ -0,0 +1,84 @@
+Tini - A tiny but valid `init` for containers
+=============================================
+
+Tini is the simplest `init` you could think of.
+
+All Tini does is spawn a single child (Tini is meant to be run in a container),
+and wait for it to exit all the while reaping zombies and performing
+signal forwarding.
+
+
+Using Tini
+----------
+
+Add Tini to your container, and make it executable. Then, just invoke Tini
+and pass your program and its arguments as arguments to Tini.
+
+In Docker, you will want to use an entrypoint so you don't have to remember
+to manually invoke Tini:
+
+    # Add Tini
+    ENV TINI_VERSION v@tini_VERSION_MAJOR@.@tini_VERSION_MINOR@.@tini_VERSION_PATCH@
+    ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
+    RUN chmod +x /tini
+    ENTRYPOINT ["/tini", "--"]
+
+    # Run your program under Tini
+    CMD ["/your/program", "-and", "-its", "arguments"]
+    # or docker run your-image /your/program ...
+
+Note that you *can* skip the `--` under certain conditions, but you might
+as well always include it to be safe. If you see an error message that
+looks like `tini: invalid option -- 'c'`, then you *need* to add the `--`.
+
+Arguments Tini itself are passed like so: `/tini -v -- /your/program`.
+The only supported argument at this time is `-v`, for extra verbosity (you can
+pass it up to 4 times, e.g. `-vvvv`).
+
+*NOTE*: The binary linked above is a 64-bit dynamically-linked binary.
+
+
+### Existing Entrypoint ###
+
+Tini can also be used with an existing entrypoint in your container!
+
+Assuming your entrypoint was `/docker-entrypoint.sh`, then you would use:
+
+    ENTRYPOINT ["/tini", "--", "/docker-entrypoint.sh"]
+
+
+### Size Considerations ###
+
+Tini is a very small file (in the 10KB range), so it doesn't add much weight
+to your container.
+
+
+### Building Tini ###
+
+If you'd rather not download the binary, you can build Tini by just running
+`make` (i.e. there is no `./configure` script).
+
+
+Understanding Tini
+------------------
+
+After spawning your process, Tini will wait for signals and forward those
+to the child process, and periodically reap zombie processes that may be
+created within your container.
+
+When the "first" child process exits (`/your/program` in the examples above),
+Tini exits as well, with the exit code of the child process (so you can
+check your container's exit code to know whether the child exited
+successfully).
+
+
+Debugging
+---------
+
+If something isn't working just like you expect, consider increasing the
+verbosity level (up to 4):
+
+    tini -v    -- bash -c 'exit 1'
+    tini -vv   -- true
+    tini -vvv  -- pwd
+    tini -vvvv -- ls

ddist.sh

@@ -17,7 +17,8 @@ docker build -t "${IMG}" .
 # Smoke test
 docker run -it --rm --entrypoint="/tini/${BIN}" "${IMG}" "-h" "--" "true"
 
-# Copy the binary
+# Copy the binary and generated README
 docker run -it --entrypoint="/bin/true" --name="${NAME}" "${IMG}"
 docker cp "${NAME}:/tini/${BIN}" "${DIST_DIR}"
+docker cp "${NAME}:/tini/README.md" "${HERE}"
 docker rm "${NAME}"