Measuring time

Accessing the current time is useful in a lot of different contexts but time is hard. It is hard to coordinate, hard to keep in sync, and this gets worse in distributed settings such as blockchains.

In CosmWasm, we solve this by passing you some information about the blockchain you are running on whenever an entrypoint is invoked.

In each of the entrypoints, you get a parameter of the type Env and this struct contains the field block. The struct contained in this field has a bunch of different information about the current state of the blockchain you are running on.

The documentation about the BlockInfo struct can be found here

The timestamp contained in this struct can be safely used in your program as the source of the current time. Well, kinda. It won’t be 100% matching the current time, as it is the timestamp of the block we are currently operating on.

But you can rely on this timestamp to have the following properties:

• Consistent across the chain (every validator on the chain has the same info)
• Monotonic (it will ever only increase or stay the same; never decrease)

Read more about BFT Time and Proposer-Based Timestamps (PBTS) if you want to better understand where the time value comes from.