The Snowplow JavaScript Tracker can now be deployed directly to Google Tag Manager via a Custom Template. This is now available in the Tag Manager Template Gallery.
There are two templates that you will need to use when setting up the Snowplow Custom Template.
Snowplow Analytics Settings Template: A variable template which can be used to easily apply a set of tracker configuration parameters to tags created with the Snowplow Analytics tag template.
Snowplow Analytics Template: Load, configure, and deploy the Snowplow JavaScript tracker library. It supports the full functionality of the JavaScript SDK.
These Custom Templates were created by Simo Ahava, full documentation can be found on his site: