Check for a connection before running db.create task (#397)

* Updated db.create task to check for a connection first before running the create.

* clean up code with already built in Process runner

* rename alias for clarity. Moved connection to private method

spec/tasks/db_create_spec.cr

@@ -0,0 +1,11 @@
+require "../spec_helper"
+
+describe Db::Create do
+  it "raises a connection error when unable to connect" do
+    Avram.temp_config(database_to_migrate: DatabaseWithIncorrectSettings) do
+      expect_raises(Avram::ConnectionError, /Failed to connect to database/) do
+        Db::Create.new(quiet: true).call
+      end
+    end
+  end
+end

src/avram/migrator/runner.cr

@@ -144,12 +144,12 @@ class Avram::Migrator::Runner
     "sudo apt-get update && sudo apt-get install postgresql postgresql-contrib".colorize(:green)
   end
 
-  def self.run(command : String)
+  def self.run(command : String, output : IO = STDOUT)
     error_messages = IO::Memory.new
     ENV["PGPASSWORD"] = self.db_password if self.db_password
     result = Process.run command,
       shell: true,
-      output: STDOUT,
+      output: output,
       error: error_messages
     ENV.delete("PGPASSWORD") if self.db_password
     unless result.success?

src/avram/tasks/db/create.cr

@@ -1,4 +1,5 @@
 class Db::Create < LuckyCli::Task
+  alias Migrator = Avram::Migrator
   summary "Create the database"
 
   def initialize(@quiet : Bool = false)
@@ -19,8 +20,26 @@ class Db::Create < LuckyCli::Task
   end
 
   def call
-    Avram::Migrator.run do
-      Avram::Migrator::Runner.create_db(@quiet)
+    attempt_to_connect
+    Migrator.run do
+      Migrator::Runner.create_db(@quiet)
     end
+  rescue
+    uri = URI.parse(connection_url)
+    raise Avram::ConnectionError.new(uri, Avram.settings.database_to_migrate)
+  end
+
+  private def connection_url : String
+    Avram::PostgresURL.build(
+      database: "",
+      hostname: Migrator::Runner.db_host.to_s,
+      username: Migrator::Runner.db_user.to_s,
+      password: Migrator::Runner.db_password.to_s,
+      port: Migrator::Runner.db_port.to_s
+    )
+  end
+
+  private def attempt_to_connect
+    Migrator::Runner.run("psql -q -l #{connection_url}", output: IO::Memory.new)
   end
 end