WIP: Generate graphql.VERSION at build stage

XXX: luarocks removes `.git` directory after cloning a repository. So
actually this approach only works when we're within our cloned
repository. So, questions:

1. We need to reprase comments acoordingly at least.
2. Whether it works with tarantoolctl rocks install in CI?

Now it is possible to obtain a version of the module using the
following code:

```lua
local graphql = require('graphql')
print(graphql.VERSION)
```

It does not work for cloned repository (without calling `tarantoolctl
rocks make`) -- the `graphql.VERSION` field will return `'unknown'`, but
it works for a user scenario: when the module is installed either from
.all.rock file or from the rockspec.

The short list of changes is the following.

- Upload all.rock instead of .src.rock for releases. I don't find a way
  to add a generated file into the .src.rock tarball using luarocks. It
  is not necessary, though: it is completely okay (and even preferable)
  to ship .all.rock for a pure Lua module.
- Upload scm-1 rockspec from CI.
- Moved from the `'builtin'` build type to `'make'` in the rockspec to
  generate the `graphql/VERSION.lua` file at the build stage.
- Added Make targets for luarocks with `graphql/VERSION.lua` file
  generation.
- Added `graphql/init.lua` file with `VERSION` field, which is filled
  from the generated `graphql/VERSION.lua` file if it is present.
  Otherwise it is filled with the `'unknown'` string.

And a couple of minor tweaks:

- Replaced `tarantoolctl rocks new_version --tag $TAG` with `sed` in the
  rockspec publication workflow, because the former strips comments and
  reformats the file. It is a thing of taste: personally I prefer to be
  able to diff rockspecs on the rock server in case of an incident.
- Use `ubuntu-latest` in rockspec publication workflow, because we have
  nothing Ubuntu version specific here. This way it requires less
  maintenance.

The publication workflow now almost the same as in expirationd, see [1].
As for me, it is good to have such code standartized.

This is reimplementation of the original #29 fix from PR #41. The key
points are the following.

- Usage the `'make'` build type allows to lower the logic down to
  luarocks level, so it works not only from CI.
- Complete the implementation by packing into .all.rock instead of
  .src.rock. Otherwise it does not work at all, see [2] for details.
- Generate the gitignored `graphql/VERSION.lua` file (don't touch
  `graphql/init.lua`) to don't leave the repository clone in a dirty
  state.

Also it is the alternative to PR #50, where the `'cmake'` build type was
proposed for the same purposes. The differences are the following.

- Use Make instead of CMake for the same of simplicity.
- Don't require tarantool-dev/devel package for building the rock or
  installing the package from the rockspec.

[1]: tarantool/expirationd#55
[2]: #46 (comment)

Follows up #29
Supersedes PR #50

Author: Totktonada

.github/workflows/publish.yml

@@ -2,26 +2,59 @@ name: Publish
 
 on:
   push:
-    tags:
-      - '*'
+    branches: [master]
+    tags: ['*']
 
 jobs:
-  publish:
+  publish-rockspec-scm-1:
+    if: github.ref == 'refs/heads/master'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: tarantool/rocks.tarantool.org/github-action@master
+        with:
+          auth: ${{ secrets.ROCKS_AUTH }}
+          files: graphql-scm-1.rockspec
+
+  publish-rockspec-tag:
     if: startsWith(github.ref, 'refs/tags/')
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+
+      # Create a rockspec for the release.
+      - run: printf '%s=%s\n' TAG "${GITHUB_REF##*/}" >> "${GITHUB_ENV}"
+      - run: sed -E
+          -e "s/branch = '.+'/tag = '${{ env.TAG }}'/g"
+          -e "s/version = '.+'/version = '${{ env.TAG }}-1'/g"
+          graphql-scm-1.rockspec > graphql-${{ env.TAG }}-1.rockspec
+
+      # Create a rock for the release (.all.rock).
+      #
+      # `tarantoolctl rocks pack <module_name> <version>` creates
+      # .all.rock tarball. It speeds up
+      # `tarantoolctl rocks install <module_name> <version>` and
+      # frees it from dependency on git.
+      #
+      # Don't confuse this command with
+      # `tarantoolctl rocks pack <rockspec>`, which creates a
+      # source tarball (.src.rock).
+      #
+      # Important: Don't upload binary rocks to
+      # rocks.tarantool.org. Lua/C modules should be packed into
+      # .src.rock instead. See [1] for description of rock types.
+      #
+      # [1]: https://github.com/luarocks/luarocks/wiki/Types-of-rocks
       - uses: tarantool/setup-tarantool@v1
         with:
-          tarantool-version: '2.8'
-
-      - run: echo "TAG=${GITHUB_REF##*/}" >> $GITHUB_ENV
-      - run: tarantoolctl rocks new_version --tag $TAG
-      - run: tarantoolctl rocks pack graphql-$TAG-1.rockspec
+          tarantool-version: '1.10'
+      - run: tarantoolctl rocks install graphql-${{ env.TAG }}-1.rockspec
+      - run: tarantoolctl rocks pack graphql ${{ env.TAG }}
 
+      # Upload .rockspec and .all.rock.
       - uses: tarantool/rocks.tarantool.org/github-action@master
         with:
           auth: ${{ secrets.ROCKS_AUTH }}
           files: |
             graphql-${{ env.TAG }}-1.rockspec
-            graphql-${{ env.TAG }}-1.src.rock
+            graphql-${{ env.TAG }}-1.all.rock

.gitignore

@@ -30,3 +30,5 @@ luacov.*.out*
 .history
 .vscode
 *.rock
+# Generated file.
+graphql/VERSION.lua

Makefile

@@ -1,5 +1,49 @@
 SHELL := /bin/bash
 
+# {{{ Build & install using luarocks
+
+PREFIX?=/usr/local
+TARANTOOL_INSTALL_LUADIR?=$(DESTDIR)$(PREFIX)/share/tarantool
+
+# https://stackoverflow.com/a/18137056/1598057
+#
+# This way everything works as expected ever for
+# `make -C /path/to/project` or
+# `make -f /path/to/project/Makefile`.
+MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
+PROJECT_DIR := $(patsubst %/,%,$(dir $(MAKEFILE_PATH)))
+
+VERSION := $(shell git -C $(PROJECT_DIR) describe --long --always)
+
+.PHONY: default
+default: build
+
+.PHONY: build
+build:
+	# Generate VERSION.lua file within the build directory.
+	mkdir -p graphql
+	printf "return '$(VERSION)'\n" > graphql/VERSION.lua
+
+.PHONY: install
+install:
+	# Install source files as is.
+	install -d -m 755 $(TARANTOOL_INSTALL_LUADIR)/graphql
+	install -m 644 $(PROJECT_DIR)/graphql/*.lua \
+		$(TARANTOOL_INSTALL_LUADIR)/graphql
+
+	# AFAIS, foo/init.lua usually normalized to foo.lua at
+	# the installation step. Let's follow this rule.
+	mv $(TARANTOOL_INSTALL_LUADIR)/graphql/init.lua \
+		$(TARANTOOL_INSTALL_LUADIR)/graphql.lua
+
+	# Copy the generated VERSION.lua file.
+	install -m 644 graphql/VERSION.lua \
+		$(TARANTOOL_INSTALL_LUADIR)/graphql/VERSION.lua
+
+# }}} Build & install using luarocks
+
+# {{{ Developer tools
+
 .PHONY: .rocks
 .rocks: graphql-scm-1.rockspec Makefile
 		tarantoolctl rocks make
@@ -23,7 +67,9 @@ test:
 clean:
 		rm -rf .rocks
 
-.PHONY: build
-build:	
+.PHONY: dev-build
+dev-build:
 		if [ ! -d ".rocks" ]; then make .rocks; fi
-		tarantoolctl rocks pack graphql scm-1	
+		tarantoolctl rocks pack graphql scm-1
+
+# }}} Developer tools

graphql-scm-1.rockspec

@@ -2,7 +2,8 @@ package = 'graphql'
 version = 'scm-1'
 
 source = {
-  url = 'git+https://github.com/tarantool/graphql.git'
+  url = 'git+https://github.com/tarantool/graphql.git',
+  branch = 'master',
 }
 
 description = {
@@ -18,17 +19,11 @@ dependencies = {
 }
 
 build = {
-  type = 'builtin',
-  modules = {
-    ['graphql.execute'] = 'graphql/execute.lua',
-    ['graphql.introspection'] = 'graphql/introspection.lua',
-    ['graphql.parse'] = 'graphql/parse.lua',
-    ['graphql.query_util'] = 'graphql/query_util.lua',
-    ['graphql.rules'] = 'graphql/rules.lua',
-    ['graphql.schema'] = 'graphql/schema.lua',
-    ['graphql.types'] = 'graphql/types.lua',
-    ['graphql.util'] = 'graphql/util.lua',
-    ['graphql.validate'] = 'graphql/validate.lua',
-    ['graphql.validate_variables'] = 'graphql/validate_variables.lua',
-  }
+  type = 'make',
+  variables = {
+      -- Support unusual tarantool location.
+      --
+      -- https://github.com/tarantool/modulekit/issues/2
+      TARANTOOL_INSTALL_LUADIR='$(LUADIR)',
+  },
 }

graphql/init.lua

@@ -0,0 +1,19 @@
+-- The VERSION.lua file is generated at two points:
+--
+-- 1. At generating the .all.rock file.
+-- 2. At installation from the rockspec.
+--
+-- As result it should exist in a user installation.
+--
+-- However we require it conditionally to allow to use directly
+-- from the repository clone. It is convenient for developers of
+-- the module.
+local ok, VERSION = pcall(require, 'graphql.VERSION')
+
+if not ok then
+    VERSION = 'unknown'
+end
+
+return {
+    VERSION = VERSION,
+}