nginx: initial support for static preseeding

Read input from STDIN on startup. If it is a tgz file, then assume it is
a node package as produced by `npm pack`. Read that tarball in and
extract the metadata from the 'package/package.json' contained in it.

Use this extracted metadata to fetch the upstream registry's metadata
for the given package and then augment the version-specific metadata for
version given in the tarball such that it looks like it was recently
published.

Use shasum to calculate the digest and then pre-seed the paths where
nginx will look for the package.json and package-X.Y.Z.tgz so that it
doesn't even bother looking upstream for them.

Author: rmg

Dockerfile

@@ -1,9 +1,9 @@
 FROM openresty/openresty:alpine
 MAINTAINER Ryan Graham <[email protected]>
 
-RUN apk --no-cache add dnsmasq
+RUN apk --no-cache add dnsmasq jq perl curl
 
-ADD entrypoint.sh nginx.conf ephemeral-npm.lua ephemeral-utils.lua /
+ADD entrypoint.sh nginx.conf ephemeral-npm.lua ephemeral-utils.lua preseed.sh /
 
 # Not port 80 because ephemeral-npm standardized on couchdb's port already
 EXPOSE 4873

entrypoint.sh

@@ -10,6 +10,8 @@
 # [ ] NPM_USER
 # [ ] NPM_PASSWORD
 
+source preseed.sh
+
 export npm_config_registry=${npm_config_registry:-https://registry.npmjs.org}
 export MAXAGE=${MAXAGE:-5m}
 
@@ -20,6 +22,9 @@ dnsmasq --listen-address=127.0.0.1 --user=root
 mkdir -p /tmp/npm/store
 mkdir -p /tmp/npm/temp
 mkdir -p /tmp/npm/cache
+
+maybePreseed
+
 # nginx runs as uid nobody and it needs write access
 chown -R nobody /tmp/npm
 

preseed.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+
+function preSeed() {
+  mkdir /tmp/seed
+  tgz=$1
+  tar -xzf $1 -C /tmp/seed
+  shasum=$(shasum $tgz | cut -d' ' -f1)
+  seedJson=/tmp/seed/package/package.json
+  upstreamJson=/tmp/seed/upstream.json
+  pkgName=$(cat $seedJson | jq -r .name)
+  pkgVersion=$(cat $seedJson | jq -r .version)
+  mkdir -p /tmp/npm/store/$pkgName
+
+  cat <<-EOF
+Preseeding with:
+  name: "$pkgName"
+  version: "$pkgVersion"
+  shasum: "$shasum"
+  tag: "latest"
+EOF
+
+  cat > /tmp/seed/seed.jq <<-EOJQ
+  .versions["$pkgVersion"] |= \$seedJson[0]
+  | .versions["$pkgVersion"].dist.shasum = \$shasum
+  | .versions["$pkgVersion"].dist.tarball = "$npm_config_registry/$pkgName/-/$pkgName-$pkgVersion.tgz"
+  | .["dist-tags"].latest = "$pkgVersion"
+EOJQ
+
+  curl -sL $npm_config_registry/$pkgName > $upstreamJson
+  jq --from-file /tmp/seed/seed.jq \
+    --slurpfile seedJson $seedJson \
+    --arg shasum $shasum \
+    --arg pkgName $pkgName \
+    --arg pkgVersion $pkgVersion \
+    $upstreamJson \
+  > /tmp/npm/store/$pkgName/package.json
+  cp $tgz /tmp/npm/store/$pkgName/$pkgName-$pkgVersion.tgz
+}
+
+function maybePreseed() {
+  echo "checking if given a tarball..."
+  cat - > /tmp/maybe.tgz
+  echo "done reading input."
+  if tar -tzf /tmp/maybe.tgz > /dev/null; then
+    preSeed /tmp/maybe.tgz
+  else
+    echo 'no pre-seed package.'
+  fi
+}