Adding a root #

Now that we have a garden to work in, we should decide on our package structure.

To create a web server, we’ll want the core server package, some tools, and some test cases.

We can start by creating the root for the core web server, by running dryad root init ./dyd/roots/server.

After creating the core web server, we need to set up the main script for the root, ./dyd/roots/server/dyd/commands/default. This script is what will be responsible for assembling a stem from the root during the build process.

Right now, we can leave it to be an empty shell script:

#!/usr/bin/env sh

After adding this line we can run dryad garden build and see output on the command line like so:

$:~/work/dryad/tutorial$ dryad garden build
[info] loading default scope: 
[info] dryad checking root server
[info] dryad building root server
[info] dryad done building root server

Note that running dryad garden build a second time does not trigger a new build of the root, since the build cache already has a record of a build for a root with those contents.

$:~/work/dryad/tutorial$ dryad garden build
[info] loading default scope: 
[info] dryad checking root server

Also note that the build created a new sprout, at ./dyd/sprouts/server. This is the resulting package from building the server root. It has almost no content right now, just two files dyd/fingerprint and dyd/traits/root-fingerprint.

dryad copies no content from roots to stems by default, which means all assets or traits we want in a stem should come from us. We can update ./dyd/roots/server/dyd/commands/default to add a little more content during the build, like adding name and version traits to the stem.

#!/usr/bin/env sh

SRC_DIR=$DYD_STEM
DEST_DIR=$1

# add the package name as a trait
mkdir -p $DEST_DIR/dyd/traits
echo -n "hello-world-server" > $DEST_DIR/dyd/traits/name
echo -n "0.0.1" > $DEST_DIR/dyd/traits/version

After this, re-running the build will update the sprout and we should be able to see the two new trait files.