Trying to use any drush command I get an error saying autoload.php won't load. It's in the vendor folder which is in the web root where I'm pretty sure it's supposed to be. It also has chmod +x permissions. If I put in php composer.phar I get the version and all that so yes it is there. If I run composer drupal-update (which composer manager would like for me to do) bash says composer: command not found. Is composer the only way to do this library thing in drupal 8? It seems a lot more problematic and less user friendly than just putting a library directory in the sites folder.
If you are getting the error -bash: composer: command not found, that means Composer is not in the
PATH Bash is using.
To use the Composer Manager module, you don't necessarily need Drush. I use it without Drush, but I run the following commands after I install the module.
cd <root directory of Drupal 8> php modules/composer_manager/scripts/init.php
If all works fine, you will see the following output:
Composer Manager has been successfully initialized.
In this way, the Composer Manager module adds a new command inside the composer.json file used by Drupal. In fact, after running those command, you will notice the following lines inside the composer.json file.
"drupal-rebuild": "Drupal\\composer_manager\\Composer\\Command::rebuild", "drupal-update": "Drupal\\composer_manager\\Composer\\Command::update"
In the case you didn't execute those commands, or they failed for any reason, running
composer drupal-update would return the following error:
Command "drupal-update" is not defined.
If you are downloading modules using Drush, just do as you normally do. The Composer Manager module will hook into Drush and do its task when a new module is downloaded.