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|
require "./database"
module Guff
class DatabaseUpdater
CURRENT_VERSION = 2_i64
SQL = {
get_version: "
SELECT value
FROM metadata
WHERE name = 'version'
",
set_version_delete: "
DELETE FROM metadata where name = 'version'
",
set_version_insert: "
INSERT INTO metadata(name, value) VALUES ('version', ?)
",
}
IDS = %w{
0-null
1-create-tables
2-create-indices
}
MIGRATIONS = {
"1-create-tables": {
backup: false,
sql: [%{
CREATE TABLE metadata (
name TEXT PRIMARY KEY,
value TEXT NOT NULL
)
}, %{
CREATE TABLE tags (
tag_id INTEGER PRIMARY KEY,
name TEXT UNIQUE NOT NULL
)
}, %{
CREATE TABLE posts (
-- unique id
post_id INTEGER PRIMARY KEY,
-- false if this post has been deleted
is_active BOOLEAN NOT NULL
DEFAULT true,
-- when this post was created
created_at TIMESTAMP WITH TIME ZONE
NOT NULL DEFAULT CURRENT_TIMESTAMP,
-- when this post was posted
-- (that is, the draft status was removed)
posted_at TIMESTAMP WITH TIME ZONE
NOT NULL DEFAULT CURRENT_TIMESTAMP,
-- title of post
name TEXT NOT NULL
CHECK (LENGTH(name) > 0),
-- slug of post (url fragment)
slug TEXT NOT NULL
CHECK (LENGTH(slug) > 0),
-- body (raw text before filters)
body TEXT NOT NULL
CHECK (LENGTH(body) > 0),
-- generated html (after filters)
html TEXT NOT NULL
CHECK (LENGTH(html) > 0)
)
}],
},
"2-create-indices": {
backup: false,
sql: [%{
CREATE INDEX in_tags_name ON tags(name)
}, %{
CREATE INDEX in_posts_slug ON posts(slug)
}],
},
}
def self.run(path, config)
new(path, config).run
end
def initialize(
@path : String,
@config : Config
)
@db = Database.new(@path)
end
def run
# get version from database
version = @db.table_exists?("metadata") ? get_version : 0_i32
puts "versions: db = %d, app = %d" % [
version,
CURRENT_VERSION,
]
if version < CURRENT_VERSION
(version + 1).upto(CURRENT_VERSION) do |v|
migrate_to(v)
end
end
end
private def migrate_to(version)
# map version number to migration id
id = IDS[version]
m = MIGRATIONS[id]
puts "migrating: %s" % [id]
@db.transaction do
# exec queries
(m[:sql] as Array(String)).each do |sql|
@db.query(sql)
end
# update database version
set_version(version)
end
end
private def get_version
(@db.one(SQL[:get_version]) || 0).to_i
end
private def set_version(version)
@db.query(SQL[:set_version_delete])
@db.query(SQL[:set_version_insert], [version])
end
end
end
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