Add META.json and a dist target for PGXN

.gitignore

@@ -9,3 +9,6 @@ results/
 regression.diffs
 regression.out
 *.diff
+
+# PGXN release archives
+plruby-*.zip

INSTALL

@@ -71,3 +71,20 @@ and TRANSFORM FOR TYPE ltree (Ruby Array of label Strings):
 
 All three accept the same PG_CONFIG/RUBY overrides and have their own
 "make installcheck".
+
+6. Packaging for PGXN (maintainers)
+-----------------------------------
+
+META.json describes the distribution for PGXN (https://pgxn.org): its version,
+the four extensions it provides, and where the sources live.  Build the release
+archive from a committed tree with:
+
+    make dist
+
+That writes plruby-<version>.zip, taking the version from META.json, and the
+archive expands into a single plruby-<version>/ directory, which is the shape
+PGXN Manager expects at https://manager.pgxn.org/upload.
+
+When cutting a release, keep the "version" field in META.json in step with
+plruby.control and the CHANGELOG, and the "provides" versions in step with the
+per-extension .control files.

META.json

@@ -0,0 +1,70 @@
+{
+   "name": "plruby",
+   "abstract": "Ruby as a procedural language for PostgreSQL",
+   "description": "PL/Ruby is a procedural language handler that embeds an MRI Ruby interpreter in the PostgreSQL backend, so functions, set-returning functions, triggers, event triggers, and procedures can be written in Ruby. Arguments and results are converted to and from native Ruby values, including nested Arrays and composites as Hashes, and numeric as a lossless String. Database access is provided through SPI (queries, prepared statements, cursors, transaction control, and subtransactions). The distribution also ships three optional TRANSFORM FOR TYPE extensions for jsonb, hstore, and ltree. PL/Ruby is untrusted: Ruby has no sandbox since 3.0 removed $SAFE, so the extension is superuser-only to install.",
+   "version": "2.5.0",
+   "maintainer": [
+      "Joshua D. Drake <jd@commandprompt.com>"
+   ],
+   "license": "mit",
+   "provides": {
+      "plruby": {
+         "abstract": "Ruby as a procedural language for PostgreSQL",
+         "file": "plruby--2.5.sql",
+         "docfile": "doc/plruby.md",
+         "version": "2.5.0"
+      },
+      "jsonb_plruby": {
+         "abstract": "Transform between jsonb and native Ruby data",
+         "file": "jsonb_plruby/jsonb_plruby--1.0.sql",
+         "version": "1.0.0"
+      },
+      "hstore_plruby": {
+         "abstract": "Transform between hstore and Ruby Hashes",
+         "file": "hstore_plruby/hstore_plruby--1.0.sql",
+         "version": "1.0.0"
+      },
+      "ltree_plruby": {
+         "abstract": "Transform between ltree and Ruby Arrays",
+         "file": "ltree_plruby/ltree_plruby--1.0.sql",
+         "version": "1.0.0"
+      }
+   },
+   "prereqs": {
+      "runtime": {
+         "requires": {
+            "PostgreSQL": "11.0.0"
+         }
+      }
+   },
+   "resources": {
+      "homepage": "https://github.com/commandprompt/plruby",
+      "bugtracker": {
+         "web": "https://github.com/commandprompt/plruby/issues"
+      },
+      "repository": {
+         "url": "https://github.com/commandprompt/plruby.git",
+         "web": "https://github.com/commandprompt/plruby",
+         "type": "git"
+      }
+   },
+   "generated_by": "Joshua D. Drake",
+   "tags": [
+      "ruby",
+      "mri",
+      "procedural language",
+      "plruby",
+      "stored procedures",
+      "triggers",
+      "spi",
+      "transform",
+      "jsonb",
+      "hstore",
+      "ltree"
+   ],
+   "meta-spec": {
+      "version": "1.0.0",
+      "url": "https://pgxn.org/meta/spec.txt"
+   },
+   "release_status": "stable"
+}

Makefile

@@ -39,3 +39,14 @@ REGRESS = init base types numspecial bytea composite encoding datetime jsonb mis
 PG_CONFIG ?= pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
 include $(PGXS)
+
+# Release archive for PGXN (https://pgxn.org).  The version is read from
+# META.json so it cannot drift from the distribution metadata; the archive
+# holds the committed tree, so commit (and tag) before building it.
+DIST_VERSION := $(shell grep -m1 '"version"' META.json | sed -e 's/[^0-9.]//g')
+
+.PHONY: dist
+dist:
+	git archive --format=zip --prefix=plruby-$(DIST_VERSION)/ \
+	    -o plruby-$(DIST_VERSION).zip HEAD
+	@echo "wrote plruby-$(DIST_VERSION).zip"