TLDR We are switching from a source-available license, to an open-source license for Earthly.We started Earthly with the mission of bringing better...
Oftentimes, to be able to deliver on a mission, you also need a way to sustain that mission long-term. For us this meant raising capital from investors and building a sustainable business around it. To protect the interests of the business, we need to create a moat1. Thus, some time ago we decided to use the source-available license Business Source License (BSL), which is like an open-source license, but with one exception: it prevents anyone from creating a competing product and also commercializing it.
There is some analogy to be drawn about the Postgres / CockroachDB case - the syntax (the Postgres SQL dialect) is open-source, which helps foster a flourishing community ecosystem full of various vendors, community tools, integrations, and interoperability. If the syntax weren’t an open standard, Cockroach wouldn’t have had an ecosystem to plug a commercial product into.
Copy-left licenses like GPL and AGPL are somewhat similar to source-available in spirit, even though they are OSI-approved. Copy-left is used as a poison pill for anyone trying to copy and build a competing product by the fact that it forces the competitor to release the code back as open-source. All while the owner of the project can still create closed-source modifications to the project to sneak in unique advantages - the owner is allowed to because they own copyright (assuming a CLA is in place - like there usually is in such cases). For similar reasons, there are several databases that use a copy-left license - it makes it hard for the competition to support differentiating features, while the original author can still have closed-source differentiators.↩︎