3-7: 🧹 Nitpick (assertive)

Consider adjusting heartbeat threshold for better stability.

While the frequent heartbeat interval (10) is good for testing, having the threshold equal to the interval (10) provides no buffer for temporary network instability. Consider increasing the threshold to provide more resilience against transient failures.

A common pattern is to set the threshold to 1.5-2x the interval. For example:

  heartbeat:
    interval: 10
-   threshold: 10
+   threshold: 15
    variance: 1

8-10: Verify if ignore_timeframe is sufficient for test stability.

The ignore_timeframe (5) being shorter than the heartbeat interval (10) could lead to premature reconnection attempts. This might contribute to the race conditions mentioned in issue #6529.

Run the following to check if other test configurations use different ratios:

#!/bin/bash
# Description: Compare heartbeat and ignore_timeframe settings across test configs
# Expected: Find configurations that might provide insights into stable ratios

echo "Searching for heartbeat and ignore_timeframe configurations in test files..."
rg -A 10 'heartbeat:|ignore_timeframe:' tests/

#!/bin/bash
# Search for code that handles reconnection logic related to these timing parameters
ast-grep --pattern 'ignore_timeframe' 

# Also search for any comments or code discussing these timing parameters
rg -g '!*.{yaml,yml}' -B 2 -A 2 'ignore_timeframe|heartbeat.*interval'

8-10: 🧹 Nitpick (assertive)

Verify ignore_timeframe in relation to heartbeat cycle.

The ignore_timeframe: 5 setting is documented as being "shorter than heartbeat cycle" (10s), which aligns with addressing potential race conditions in peer announcements.

However, we should ensure this value:

1. Is sufficient to prevent false negatives in peer connectivity
2. Doesn't mask actual connectivity issues

Let's verify the impact on peer connectivity:

#!/bin/bash
# Description: Check for any hardcoded timeouts or related timing constants
# that might conflict with this ignore_timeframe

echo "Checking for related timing constants:"
rg -A 2 "timeout|delay|interval" "src/**/*.rs"

Consider documenting:

1. The rationale behind choosing 5 seconds
2. How this value interacts with the heartbeat interval
3. Any minimum/maximum bounds for this value

3-7: 🧹 Nitpick (assertive)

Verify heartbeat timing parameters against network latency.

The heartbeat configuration introduces frequent checks with:

• 10-second interval
• 10-second threshold
• 1-second variance

While these values might help address the E2E test failures by increasing responsiveness, we should verify if they're appropriate for CI environment network conditions.

Let's check other config files for consistency:

Consider adding comments explaining:

1. Why these specific timing values were chosen
2. How they relate to the CI environment requirements
3. The relationship between interval and threshold

#!/bin/bash
# Description: Check heartbeat settings across all config files
# Expected: Similar heartbeat settings in related test configs

echo "Checking heartbeat settings in all config files:"
rg -A 3 "heartbeat:" "tests/*.yaml" "example*.yaml"

#!/bin/bash
# Let's try with fd to find yaml files first and then search in them
echo "Finding all yaml/yml files:"
fd -e yaml -e yml

echo -e "\nChecking heartbeat settings in these files:"
fd -e yaml -e yml -x rg -A 3 "heartbeat:"

3-7: 🧹 Nitpick (assertive)

Review heartbeat threshold configuration.

The heartbeat threshold being equal to the interval (both set to 10) might be too strict. If a single heartbeat is delayed or missed, it could immediately trigger unwanted peer disconnections. Consider increasing the threshold to allow for some network latency and jitter.

Suggested approach:

• Set threshold to at least 2-3 times the interval (e.g., threshold: 20 or 30)
• This provides better tolerance for temporary network issues while still detecting genuinely offline peers

8-10: 🧹 Nitpick (assertive)

Verify ignore_timeframe value relative to heartbeat cycle.

The ignore_timeframe (5) is set to half the heartbeat interval (10). This could lead to race conditions where legitimate network events are ignored if they occur just before a heartbeat check.

Let's check if other configuration files maintain consistent timing relationships:

Consider:

• Setting ignore_timeframe closer to the heartbeat interval (e.g., 8-9)
• Or adding documentation explaining why 5 is the optimal value for preventing the race conditions mentioned in issue #6529

10-11: Verify the impact of reduced quality thresholds on network stability.

The significant reduction in quality thresholds (OFFLINE: 0.5→0.0, BAD_QUALITY: 0.2→0.1) makes the network more lenient in handling poor connections. While this may help with test stability, please verify that:

1. These thresholds don't mask actual network issues
2. The network remains stable with potentially more poor-quality connections

#!/bin/bash
# Search for test files that verify network stability
rg -l "network.*stability|quality.*threshold" --type rust

#!/bin/bash
# Check how these thresholds are used in network quality decisions
rg -A 5 "DEFAULT_NETWORK_.*QUALITY_THRESHOLD" --type rust

# Look for quality-related tests
rg -B 2 -A 5 "test.*quality" --type rust

# Search for network quality assessment logic
ast-grep --pattern 'fn $_(quality: $_, $$$) { $$$ }'

#!/bin/bash
# Check how network quality affects connection decisions
rg -B 2 -A 5 "quality.*threshold" transport/network/src/network.rs

# Look for quality-related state handling
ast-grep --pattern 'fn $_(quality: f64, $$$) { $$$ }'

# Check for quality validation logic
rg -B 2 -A 5 "validate.*quality" --type rust

189-189: LGTM: Reasonable adjustment to bad quality threshold.

The reduction of quality_bad_threshold from 0.2 to 0.1 provides a more lenient threshold for marking node connectivity as "bad", which aligns with making the network behavior more robust while still maintaining reasonable quality standards.

191-191: Verify impact of aggressive offline threshold.

While setting quality_offline_threshold to 0.0 helps quickly identify truly offline nodes and may improve E2E test reliability, it's worth verifying that this aggressive threshold doesn't cause issues in production environments with temporary network instability.

The surrounding configuration provides safeguards:

• quality_step: 0.1 ensures gradual quality adjustments
• quality_avg_window_size: 25 provides smoothing effect
• Backoff parameters allow for gradual reconnection attempts

Let's verify the E2E test improvements with these new thresholds:

174-175: LGTM! Good improvement to code readability.

Extracting the quality calculation into a variable improves code clarity and prevents potential double calculation.

Line range hint 201-206: Document recommended values for libp2p connection limits.

Given that this PR addresses network stability and E2E test failures (issue #6529), it would be helpful to document recommended values for:

• HOPR_INTERNAL_LIBP2P_MAX_CONCURRENTLY_DIALED_PEER_COUNT
• HOPR_INTERNAL_LIBP2P_MAX_NEGOTIATING_INBOUND_STREAM_COUNT

These limits could help prevent race conditions during peer connections.

Let's check if there are any recommended values in the codebase:

#!/bin/bash
# Search for default values or documentation of these variables
rg -A 3 "HOPR_INTERNAL_LIBP2P_MAX"

#!/bin/bash
# Search for the default constants
rg "HOPR_SWARM_CONCURRENTLY" transport/p2p/src/constants.rs

240-241: LGTM: Improved peer quality threshold handling

The simplified logic for peer quality thresholds makes the code more robust and less prone to race conditions. The changes align well with the PR objectives to fix network heartbeat behavior.

Also applies to: 254-258

292-296: LGTM: Well-implemented connected peers retrieval

The new connected_peers method effectively filters peers based on the quality threshold, supporting the PR's goal to fix the /node/peers endpoint. The implementation is concise and leverages existing functionality.

299-299: LGTM: Appropriate visibility restriction

Reducing the visibility of peer_filter to pub(crate) is a good practice as it minimizes the public API surface while maintaining necessary access within the crate.

1269-1269: LGTM!

The method simplification enhances readability and aligns with the updated network interaction logic.