sequencing/metrics.go (2)

16-33: LGTM: Metrics struct provides a comprehensive set of initial metrics.

The Metrics struct aligns well with the PR objectives, providing valuable insights for rollup developers. It includes metrics for gas price, blob size, transaction status, pending blocks, and included block height.

I noticed TODO comments for potential future metrics (gas used, wallet balance, cost per byte). Would you like me to create GitHub issues to track these enhancements?

---

1-86: Great implementation of the metrics system!

The metrics.go file provides a comprehensive and well-structured metrics system for the sequencer, aligning perfectly with the PR objectives. The implementation follows Prometheus best practices and offers flexibility through custom labeling.

Next steps to consider:

1. Implement the additional metrics mentioned in the TODO comments (gas used, wallet balance, cost per byte).
2. Create unit tests for the PrometheusMetrics and NopMetrics functions to ensure their correctness.
3. Document how these metrics should be used and interpreted by rollup developers.

Overall, this is a solid foundation for the metrics system that will greatly benefit rollup developers in making informed decisions.

go.mod (1)

8-11: Consider updating go-kit to the latest version.

The addition of github.com/go-kit/kit and github.com/prometheus/client_golang as direct dependencies aligns well with the PR objectives for implementing metrics. However, go-kit is currently set to version v0.13.0, while the latest version is v0.14.0.

Consider updating github.com/go-kit/kit to v0.14.0 to ensure you have the latest features and bug fixes:

-	github.com/go-kit/kit v0.13.0
+	github.com/go-kit/kit v0.14.0

The github.com/prometheus/client_golang v1.19.1 dependency is up-to-date and appropriate for implementing Prometheus metrics.

da/da.go (1)

197-197: LGTM with suggestion: Update to SubmitBatch method

The population of the BlobSize field in the SubmitBatch method is consistent with its addition to the BaseResult struct. This provides valuable information about the total size of the submitted batch, which aligns with the PR objectives.

However, consider adding a check for potential overflow when calculating blobSize. Although unlikely, if the total size of all blobs exceeds the maximum value of uint64, it could lead to unexpected behavior.

Consider adding an overflow check, for example:

if blobSize+uint64(len(blob)) < blobSize {
    // Handle overflow
    message = "Blob size overflow detected"
    log.Warn(message)
    break
}

sequencing/sequencer.go (3)

126-127: LGTM! Consider initializing the metrics field.

The addition of the metrics field to the Sequencer struct is a good way to incorporate metrics tracking. However, ensure that this field is properly initialized in the NewSequencer function to avoid potential nil pointer dereferences.

Consider updating the NewSequencer function to initialize the metrics field:

func NewSequencer(daAddress, daAuthToken string, daNamespace []byte, batchTime time.Duration) (*Sequencer, error) {
    // ... existing code ...
    s := &Sequencer{
        // ... existing fields ...
+       metrics: NewMetrics(), // Assuming there's a NewMetrics() function
    }
    // ... rest of the function ...
}

---

187-193: LGTM! Consider adding error handling for metric updates.

The recordMetrics method is well-structured and updates the relevant metrics. However, some metrics libraries' Set methods can return errors, which are currently not being handled.

Consider adding error handling for each metric update:

func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, status da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {
-   c.metrics.GasPrice.Set(float64(gasPrice))
-   c.metrics.LastBlobSize.Set(float64(blobSize))
-   c.metrics.TransactionStatus.Set(float64(status))
-   c.metrics.NumPendingBlocks.Set(float64(numPendingBlocks))
-   c.metrics.IncludedBlockHeight.Set(float64(includedBlockHeight))
+   if err := c.metrics.GasPrice.Set(float64(gasPrice)); err != nil {
+       log.Error("Failed to set GasPrice metric", "error", err)
+   }
+   // Repeat for other metrics...
}

This change will help catch and log any errors that occur during metric updates, aiding in debugging and monitoring.

---

256-257: LGTM! Consider consistent error handling.

The addition of the recordMetrics call in the submitBatchToDA method is well-placed to capture metrics after each submission attempt. This aligns well with the PR objectives of introducing metrics for DA submission data.

For consistency with other error handling in this method, consider wrapping the recordMetrics call in an error check:

-   c.recordMetrics(gasPrice, res.BlobSize, res.Code, len(batchesToSubmit), res.DAHeight)
+   if err := c.recordMetrics(gasPrice, res.BlobSize, res.Code, len(batchesToSubmit), res.DAHeight); err != nil {
+       log.Error("Failed to record metrics", "error", err)
+   }
    attempt += 1

This change assumes that recordMetrics is updated to return an error as suggested in the previous comment. It maintains consistency with the error handling approach used elsewhere in this method.

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main.go (1)

Line range hint 1-95: Overall assessment: Good implementation with a minor improvement needed.

The changes successfully introduce Prometheus metrics functionality as per the PR objectives. The implementation is well-integrated into the existing code structure. However, there's a minor issue with the order of operations in the metrics server setup that should be addressed.

Key points:

1. Metrics-related imports, variables, and flags are correctly added.
2. The metrics server is set up in a non-blocking manner using a goroutine.
3. The NewSequencer call is properly updated to include the metrics parameter.

Please address the suggested reordering of operations in the metrics server setup to ensure the /metrics endpoint is always available when the server starts.

sequencing/metrics.go (2)

58-88: Review metric names and help descriptions for clarity and consistency

The names and help descriptions of the metrics should be clear and consistently formatted to enhance usability in monitoring tools. For example:

• The GasPrice metric's help text is "The gas price of DA." Consider specifying the unit (e.g., wei, gwei) for clarity.
• The IncludedBlockHeight metric's name could be more descriptive, such as last_included_block_height, to clearly indicate its purpose.

---

91-100: Ensure NopMetrics covers all metrics for consistency

Currently, the NopMetrics function initializes all metrics except for CostPerByte and WalletBalance, which are commented out in the Metrics struct. Once you decide to implement or remove those metrics, ensure that NopMetrics is updated accordingly to maintain consistency.

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sequencing/metrics.go (2)

10-17: LGTM: Constants and type definitions are well-defined.

The MetricsSubsystem constant and MetricsProvider type are appropriately defined. The function type for MetricsProvider allows for flexible metrics creation based on the chain ID.

Consider adding a brief comment explaining the purpose of the MetricsProvider type, similar to the comment for MetricsSubsystem. This would enhance code readability and documentation.

---

1-100: Overall implementation is good, but some additions are needed to fully meet PR objectives.

The metrics.go file implements a well-structured metrics system for the sequencer, providing both Prometheus-based and no-op metrics. The implementation is flexible and allows for easy enabling/disabling of metrics collection.

However, to fully meet the PR objectives and address the requirements from issue #1126, consider the following improvements:

1. Implement the missing metrics:

   • DA cost or burn rate
   • Current wallet balance of the DA batch signer
   • Details about the latest DA bundles submitted, including success rates

2. Add functionality to expose these metrics in a format suitable for visualization in a dashboard like Grafana.

3. Ensure that all implemented metrics provide valuable insights for rollup developers to make informed decisions about their rollups.

To implement these improvements:

1. Add new fields to the Metrics struct for the missing metrics.
2. Implement methods to update these metrics based on the sequencer's operations.
3. Consider adding a method or separate function to export all metrics in a format suitable for Grafana or similar dashboarding tools.

Would you like assistance in implementing these additional features to fully meet the PR objectives?

🧰 Tools

🪛 GitHub Check: lint / golangci-lint

[failure] 1-1:
: # github.com/rollkit/centralized-sequencer/sequencing [github.com/rollkit/centralized-sequencer/sequencing.test]

sequencing/sequencer.go (4)

127-129: LGTM! Consider adding comments for new fields.

The addition of metricsProvider and metrics fields to the Sequencer struct aligns well with the PR objectives for implementing metrics reporting. This change provides a foundation for collecting and managing metrics data.

Consider adding brief comments to explain the purpose of these new fields, especially for metricsProvider, to improve code readability:

 type Sequencer struct {
     // ... existing fields ...
+    // metricsProvider creates metrics instances for specific rollup IDs
     metricsProvider MetricsProvider
+    // metrics holds the current metrics data for the sequencer
     metrics *Metrics
 }

---

152-153: LGTM! Consider clarifying the metrics initialization process.

The initialization of metricsProvider and metrics fields in the NewSequencer function is appropriate. Using NopMetrics() as an initial value for metrics is a good practice, providing a no-op implementation until the actual metrics are set up.

To improve clarity, consider adding a brief comment explaining why metrics is initialized with NopMetrics() and will be properly set later:

     metricsProvider: metricsProvider,
-    metrics: NopMetrics(), // Initialized from metricsProvider in SubmitRollupTransaction
+    metrics: NopMetrics(), // Temporary no-op metrics; will be initialized with actual metrics in SubmitRollupTransaction

---

191-197: LGTM! Consider adding error handling for metric recording.

The recordMetrics method is a great addition that aligns well with the PR objectives. It captures important metrics related to DA submission data, providing valuable insights for rollup developers as outlined in issue #1126.

Consider adding error handling for metric recording operations. While unlikely, errors in metric recording shouldn't affect the main functionality:

 func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, status da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {
-    c.metrics.GasPrice.Set(float64(gasPrice))
-    c.metrics.LastBlobSize.Set(float64(blobSize))
-    c.metrics.TransactionStatus.Set(float64(status))
-    c.metrics.NumPendingBlocks.Set(float64(numPendingBlocks))
-    c.metrics.IncludedBlockHeight.Set(float64(includedBlockHeight))
+    if err := c.metrics.GasPrice.Set(float64(gasPrice)); err != nil {
+        log.Errorf("Failed to record GasPrice metric: %v", err)
+    }
+    // Repeat for other metrics...
 }

---

304-305: LGTM! Consider adding error handling for metrics initialization.

The initialization of the metrics field using the metricsProvider when the rollupId is first set is a good approach. This ensures that metrics are properly initialized for each specific rollup ID, which is particularly useful in multi-rollup scenarios.

Consider adding error handling for the metrics initialization:

 if c.rollupId == nil {
     c.rollupId = rollupId
-    c.metrics = c.metricsProvider(hex.EncodeToString(rollupId))
+    metrics, err := c.metricsProvider(hex.EncodeToString(rollupId))
+    if err != nil {
+        log.Errorf("Failed to initialize metrics for rollup ID %s: %v", hex.EncodeToString(rollupId), err)
+        // Consider using NopMetrics() as a fallback
+        c.metrics = NopMetrics()
+    } else {
+        c.metrics = metrics
+    }
 } else {
     // ... existing code ...
 }

This change ensures that the system can continue to function even if there's an issue with metrics initialization, while also logging the error for debugging purposes.

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main.go (1)

79-80: LGTM: Metrics integration with NewSequencer, but TODO needs addressing.

The integration of metrics with the NewSequencer function is correct and aligns with the changes in the sequencing package. However, there's a TODO comment that needs to be addressed:

metrics := sequencing.DefaultMetricsProvider(metricsEnabled)("") // TODO use rollupId as chain_id

Please replace the empty string with the appropriate rollupId when it's available. This will ensure that the metrics are properly associated with the specific rollup chain.

sequencing/sequencer_test.go (3)

54-54: LGTM! Consider adding a comment for clarity.

The addition of NopMetrics() as the last parameter to NewSequencer is correct and aligns with the updated method signature. This change allows for metrics functionality in the Sequencer, which is beneficial for monitoring and debugging.

Consider adding a brief comment explaining the purpose of NopMetrics() for better code readability:

-	seq, err := NewSequencer(MockDAAddressHTTP, "authToken", []byte("namespace"), 10*time.Second, NopMetrics())
+	// Use NopMetrics() for testing as we don't need actual metrics collection
+	seq, err := NewSequencer(MockDAAddressHTTP, "authToken", []byte("namespace"), 10*time.Second, NopMetrics())

---

66-66: LGTM! Consider consistent formatting.

The addition of NopMetrics() as the last parameter to NewSequencer is correct and consistent with the previous change.

For consistency with the previous test function, consider adding a similar comment explaining the use of NopMetrics():

-	seq, err := NewSequencer(MockDAAddressHTTP, "authToken", []byte("namespace"), 10*time.Second, NopMetrics())
+	// Use NopMetrics() for testing as we don't need actual metrics collection
+	seq, err := NewSequencer(MockDAAddressHTTP, "authToken", []byte("namespace"), 10*time.Second, NopMetrics())

---

Line range hint 1-186: Consider expanding metrics implementation to meet PR objectives.

The changes in this file successfully introduce metrics functionality to the Sequencer in test cases, which is a step towards meeting the PR objectives. However, to fully address the goals outlined in the PR summary and linked issue #1126, consider the following suggestions:

1. Implement actual metrics collection in the main Sequencer implementation.
2. Add specific metrics for DA submission data, such as DA cost, burn rate, and latest DA bundle details.
3. Create new test cases that verify the correct collection and reporting of these metrics.
4. Ensure that the metrics can be easily integrated with visualization tools like Grafana, as mentioned in the objectives.

Would you like assistance in planning or implementing these additional features to fully meet the PR objectives?

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README.md (1)

57-58: LGTM! Consider adding a note about metrics usage.

The new flags for metrics are well-documented and consistent with the existing table. They align with the PR objectives of adding metrics functionality.

To provide more context for users, consider adding a brief note after the table explaining how to access the metrics once enabled. For example:

Note: When metrics are enabled, they can be accessed at the specified metrics-address (e.g., http://localhost:8080/metrics).

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main.go (3)

49-50: Consider enhancing metrics configuration.

While the flag definitions are functional, consider these improvements:

1. Add validation for the metrics address format
2. Document potential port conflicts in the help text
3. Consider using a less common default port to avoid conflicts

-	flag.StringVar(&metricsAddress, "metrics-address", ":8080", "Address to expose Prometheus metrics")
+	flag.StringVar(&metricsAddress, "metrics-address", ":9090", "Address to expose Prometheus metrics (format: [host]:port)")

---

81-82: Document metrics implementation details.

The metrics integration lacks documentation about:

1. The purpose of the empty string parameter in metrics("")
2. What metrics are being collected
3. How these metrics align with the PR objectives (DA submission data)

Consider adding comments explaining the metrics implementation and its relationship to the DA metrics requirements from issue #1126.

---

81-82: Consider architectural improvements for observability.

To enhance the observability stack:

1. Add a health check endpoint alongside metrics
2. Implement proper shutdown handling for both gRPC and metrics servers
3. Consider adding a readiness probe
4. Document the metrics format and dashboard setup (e.g., Grafana)

This would provide a more complete observability solution for rollup developers.

sequencing/metrics.go (1)

1-95: Consider adding more rollup-specific metrics.

While the current implementation provides a good foundation for basic DA metrics, consider adding more rollup-specific metrics that would help developers make informed decisions, such as:

• Average DA submission latency
• DA submission success rate over time
• DA cost trends
• Bundle size distribution

These metrics would provide valuable insights for rollup developers as mentioned in issue #1126.

README.md (1)

57-58: Enhance metrics documentation while the changes look good.

The new flags are correctly documented and align with the PR objectives. However, to better serve rollup developers (as mentioned in issue #1126), consider enhancing the documentation with:

1. A new section describing the available metrics and their purposes
2. Examples of querying these metrics
3. Basic setup instructions for visualizing these metrics in Grafana

Example addition:

 | `metrics-address` |address to expose prometheus metrics|`":8080"`|
 <!-- markdownlint-enable MD013 -->
+
+## Metrics
+
+When enabled with the `metrics` flag, the following Prometheus metrics are exposed at `http://<metrics-address>/metrics`:
+
+| Metric Name | Type | Description |
+|------------|------|-------------|
+| da_submission_size_bytes | Gauge | Size of DA submissions in bytes |
+| da_submission_cost | Gauge | Cost of DA submissions |
+| da_wallet_balance | Gauge | Current wallet balance of the DA batch signer |
+
+### Visualizing Metrics
+
+To visualize these metrics in Grafana:
+
+1. Configure Prometheus to scrape metrics from the sequencer's metrics endpoint
+2. Import the [example dashboard](./grafana/dashboards/da-metrics.json)

go.mod (1)

9-9: Consider upgrading go-kit to the latest version.

While v0.13.0 is stable, consider upgrading to the latest version (v0.14.0) for potential improvements and bug fixes.

-	github.com/go-kit/kit v0.13.0
+	github.com/go-kit/kit v0.14.0

sequencing/sequencer_test.go (1)

70-70: Consider replacing sleep with proper synchronization.

While the addition of NopMetrics() is good, the test relies on a fixed sleep duration which could be flaky. Consider using a more reliable synchronization mechanism like channels or polling with timeout to verify transaction processing.

Example approach:

// Instead of sleep, poll until the transaction appears or timeout
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
for {
    nextBatchresp, err := seq.GetNextBatch(ctx, sequencing.GetNextBatchRequest{RollupId: rollupId, LastBatchHash: nil})
    if err != nil {
        t.Fatal(err)
    }
    if len(nextBatchresp.Batch.Transactions) > 0 {
        break
    }
    select {
    case <-ctx.Done():
        t.Fatal("timeout waiting for transaction")
    case <-time.After(100 * time.Millisecond):
        continue
    }
}

Also applies to: 80-81

sequencing/sequencer.go (2)

497-505: Optimize metric recording by handling nil checks within Metrics methods

Currently, there's a nil check for c.metrics before setting each metric. If the Metrics methods already handle nil checks internally, this external check may be redundant.

Consider simplifying the code by removing the outer nil check if it's safe to do so.

-func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, status da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {
-    if c.metrics != nil {
-        c.metrics.GasPrice.Set(float64(gasPrice))
-        c.metrics.LastBlobSize.Set(float64(blobSize))
-        c.metrics.TransactionStatus.Set(float64(status))
-        c.metrics.NumPendingBlocks.Set(float64(numPendingBlocks))
-        c.metrics.IncludedBlockHeight.Set(float64(includedBlockHeight))
-    }
+func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, status da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {
+    c.metrics.GasPrice.Set(float64(gasPrice))
+    c.metrics.LastBlobSize.Set(float64(blobSize))
+    c.metrics.TransactionStatus.Set(float64(status))
+    c.metrics.NumPendingBlocks.Set(float64(numPendingBlocks))
+    c.metrics.IncludedBlockHeight.Set(float64(includedBlockHeight))
 }

---

568-568: Ensure recordMetrics is called only when metrics are enabled

Before calling c.recordMetrics(...), verify that metrics are enabled to prevent potential nil pointer exceptions if c.metrics is nil.

Add a nil check or ensure that c.metrics is always initialized when metrics are enabled.

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main.go (4)

38-39: LGTM: Well-structured metrics configuration.

The metrics configuration flags are well-defined with appropriate defaults. However, consider adding a note in the documentation about securing the metrics endpoint in production environments, as it may expose sensitive information.

Consider implementing authentication or network-level controls for the metrics endpoint in production deployments.

Also applies to: 49-50

---

73-73: Document security implications of #nosec.

The #nosec G114 directive bypasses the security check for non-TLS HTTP usage. Please document why TLS is not required in this context.

Add a comment explaining the security implications and why it's safe to bypass TLS for metrics in this case.

---

81-82: Document metrics provider parameter usage.

The empty string passed to metrics("") needs documentation explaining its purpose.

Add a comment explaining what this parameter represents and why an empty string is appropriate here.

---

Line range hint 38-82: Consider adding metrics documentation.

While the implementation aligns with the PR objectives, consider adding documentation that:

1. Lists the available metrics and their meanings
2. Provides example Grafana queries/dashboards
3. Explains the metrics data retention policy

This would help rollup developers better utilize these metrics for decision-making, as outlined in issue #1126.

sequencing/metrics.go (2)

36-40: Consider removing or addressing the TODO comments

The TODOs for gas used and wallet balance metrics indicate pending work. If these metrics are not planned for immediate implementation, consider removing the comments to keep the codebase clean. Alternatively, if you plan to implement them soon, I can assist with adding these metrics.

Would you like help in implementing these metrics or opening a GitHub issue to track this task?

---

62-86: Enhance metric Help descriptions for clarity

Consider providing more detailed descriptions for the metrics to improve observability and maintainability. Clear Help text assists in understanding the purpose and usage of each metric.

Apply this diff to enhance the descriptions:

 Help:      "The gas price of DA.",
+// Example: "The current gas price used for Data Availability transactions."
 
 Help:      "The size in bytes of the last DA blob.",
+// Example: "Size in bytes of the most recently submitted Data Availability blob."
 
 Help:      "The last DA included block height.",
+// Example: "The block height at which the last Data Availability submission was included."

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main.go (2)

49-50: Consider adding address validation

While the default metrics address is reasonable, it would be beneficial to validate the format of user-provided addresses to prevent runtime errors.

 flag.StringVar(&metricsAddress, "metrics-address", ":8080", "Address to expose Prometheus metrics")
+if metricsEnabled {
+    host, port, err := net.SplitHostPort(metricsAddress)
+    if err != nil {
+        log.Fatalf("Invalid metrics address format: %v", err)
+    }
+}

---

81-82: Consider adding more DA-specific metrics

Based on the PR objectives from issue #1126, consider adding these metrics:

• DA cost/burn rate
• Current wallet balance of DA batch signer
• Latest DA bundles submission stats

This would provide valuable insights for rollup developers.

sequencing/sequencer.go (2)

487-495: Add documentation for metrics recording

Consider adding documentation to explain the purpose and significance of each metric being recorded. This will help maintainers understand the metrics' importance and expected values.

Add this documentation above the function:

+// recordMetrics records various metrics related to DA submission:
+// - gasPrice: The current gas price used for submission
+// - blobSize: Size of the last submitted blob
+// - status: Submission status code
+// - numPendingBlocks: Number of blocks waiting to be submitted
+// - includedBlockHeight: Height at which the submission was included
 func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, status da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {

---

Line range hint 673-673: Consider implementing DA verification

The TODO comment indicates that DA verification needs to be added. Since this PR focuses on metrics, would you like me to create a separate issue to track the implementation of DA verification?

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main.go (1)

49-50: Consider using a less common default port

The default metrics port :8080 is commonly used by other services and might lead to conflicts. Consider using a less common port (e.g., :9090 which is Prometheus's default) or documenting potential conflicts in the README.

sequencing/sequencer.go (2)

Line range hint 289-323: Add nil check for metrics parameter.

While the metrics integration looks good, consider adding a nil check for the metrics parameter to prevent potential panics if nil is passed. This would make the constructor more robust.

 func NewSequencer(daAddress, daAuthToken string, daNamespace []byte, batchTime time.Duration, metrics *Metrics, dbPath string) (*Sequencer, error) {
+    if metrics == nil {
+        return nil, fmt.Errorf("metrics cannot be nil")
+    }
     ctx := context.Background()

---

487-495: Add documentation for recordMetrics method.

Consider adding documentation to explain the purpose of this method and its parameters. This would improve code maintainability and help other developers understand the metrics being recorded.

+// recordMetrics records various metrics related to DA submission:
+// - gasPrice: The current gas price used for submission
+// - blobSize: Size of the submitted blob in bytes
+// - statusCode: Status code of the DA submission attempt
+// - numPendingBlocks: Number of blocks pending submission
+// - includedBlockHeight: Height at which the submission was included
 func (c *Sequencer) recordMetrics(gasPrice float64, blobSize uint64, statusCode da.StatusCode, numPendingBlocks int, includedBlockHeight uint64) {

sequencing/metrics.go (1)

39-41: Remove commented-out code for clarity

The CostPerByte and WalletBalance metrics are commented out in the Metrics struct. If these metrics are not planned for future use, consider removing them to keep the codebase clean. If they are intended for future implementation, adding a // TODO comment would make the intent clear.

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main.go (2)

50-51: Enhance flag descriptions for better usability

While the flag definitions are correct, consider providing more detailed descriptions to help users understand:

• The metrics endpoint path (/metrics)
• The Prometheus format
• Port considerations

-flag.BoolVar(&metricsEnabled, "metrics", false, "Enable Prometheus metrics")
+flag.BoolVar(&metricsEnabled, "metrics", false, "Enable Prometheus metrics endpoint at /metrics")
-flag.StringVar(&metricsAddress, "metrics-address", ":8080", "Address to expose Prometheus metrics")
+flag.StringVar(&metricsAddress, "metrics-address", ":8080", "Address to expose Prometheus metrics (format: host:port)")

---

107-111: Add timeout to metrics server shutdown

While the graceful shutdown is implemented correctly, consider adding a timeout to prevent hanging during shutdown.

 if metricsServer != nil {
-	if err := metricsServer.Shutdown(context.Background()); err != nil {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	if err := metricsServer.Shutdown(ctx); err != nil {
 		log.Printf("Error shutting down metrics server: %v", err)
 	}
 }

sequencing/metrics.go (2)

18-19: Add documentation for the chainID parameter.

Consider enhancing the documentation to explain the purpose and format of the chainID parameter.

-// MetricsProvider returns sequencing Metrics.
+// MetricsProvider returns sequencing Metrics for a specific chain identified by chainID.
+// The chainID parameter is used to label metrics for multi-chain deployments.
 type MetricsProvider func(chainID string) (*Metrics, error)

---

32-48: Consider adding additional metrics from PR objectives.

The current implementation provides good basic metrics, but consider adding more metrics mentioned in the PR objectives:

• DA cost or burn rate per submission
• Success rates for DA bundles

These additional metrics would provide more comprehensive insights for rollup developers. Would you like help implementing these metrics?

sequencing/sequencer.go (1)

487-495: Optimize status code string conversion

The status code conversion to string can be simplified.

Apply this diff to optimize the code:

-		c.metrics.TransactionStatus.With("status", fmt.Sprintf("%d", statusCode)).Add(1)
+		c.metrics.TransactionStatus.With("status", strconv.Itoa(int(statusCode))).Add(1)

Don't forget to add the import:

import "strconv"

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#!/bin/bash
# Search for DA-related metrics definitions
echo "Searching for DA metrics definitions..."
rg -l "prometheus.*NewCounter.*da|prometheus.*NewGauge.*da|prometheus.*NewHistogram.*da" --type go

# Search for DA metric recording points
echo "Searching for DA metric recording points..."
rg "metrics\.(Record|Observe|Inc|Set).*da" --type go

#!/bin/bash
# Let's try a broader search for metrics-related code in the sequencing package
echo "Searching for metrics-related code in sequencing package..."
rg "metrics" --type go -C 3

# Look for the DefaultMetricsProvider implementation
echo "Looking for DefaultMetricsProvider implementation..."
ast-grep --pattern 'func DefaultMetricsProvider'

# Search for any prometheus metric definitions
echo "Searching for prometheus metric definitions..."
rg "prometheus.New(Counter|Gauge|Histogram)" --type go -C 2