github: add update script

1 files changed, 15 insertions, 0 deletions

diff --git a/krebs/3modules/github/update b/krebs/3modules/github/update
new file mode 100755
index 00000000..3952daba
--- /dev/null
+++ b/krebs/3modules/github/update
@@ -0,0 +1,15 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p cidr2glob curl git jq
+
+# update known-hosts.json
+#
+# usage: ./update
+
+set -efu
+
+# XXX IPv6 addresses are currently ignored
+curl -sS https://api.github.com/meta | jq -r .git[] | grep -v : | cidr2glob | jq -Rs 'split("\n")|map(select(.!=""))' > known-hosts.json
+
+if git diff --exit-code known-hosts.json; then
+  echo known-hosts.json is up to date: nothing to do >&2
+fi