cometbft_consensus_height Metric Unavailable During Fast Syncing

[smuu]

Summary of Bug

I wonder if this is a bug or wanted behavior.

The metric cometbft_consensus_height is not exposed as long cometbft_consensus_fast_syncing is true.

I expect the metric cometbft_consensus_height to be available even if the node is actively syncing.

Version

v1.7.0

Steps to Reproduce

• Enable Prometheus metrics in the config
• Start a new consensus full node
• Look at the Prometheus metrics endpoint
• See that cometbft_consensus_fast_syncing is 1 and cometbft_consensus_height is not registered/available
• Once the node is synced, cometbft_consensus_fast_syncing is 0 and cometbft_consensus_height is not available

[cmwaters]

This is to be expected but not desired. When "fast syncing" a different component is responsible for executing the blocks and thus consensus actually doesn't know what the current height is. If this is causing some issues elsewhere, we can look into fixing it else I'd just leave it as is

[smuu]

From the point of view of alerting, it would make sense to initialize the metric during the application's startup and update it as soon it is available.