[ENG-2320] Refactor browse method to use worker pattern #121
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WalkthroughThe pull request introduces a significant refactoring of the OPC UA browsing functionality in the Changes
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Actionable comments posted: 0
🧹 Nitpick comments (7)
opcua_plugin/browse.go (6)
65-66: Clarify intended usage or visibilityAlthough documented as "avoid using this function directly," it is exported. Consider renaming or adding explicit comments if its usage is truly meant to be restricted to test scenarios.
69-75: Document struct fieldsThe
NodeTaskstruct plays a crucial role in controlling recursion depth and mapping parent IDs. Consider adding inline doc comments for each field to enhance maintainability and readability.
77-79: Reduce parameter overloadThe
browsefunction’s signature has many parameters. Grouping them into a dedicated configuration struct would improve clarity and maintainability.
81-84: Make worker count configurableHardcoding
numWorkers = 100may limit flexibility. Consider allowing a configurable value or an adaptive strategy based on workload.
110-121: Simplify worker signatureSimilar to
browse, the worker function accepts numerous parameters. You could encapsulate them in aWorkerContextstruct to reduce parameter churn.
323-323: Check concurrency impactEach
browseinvocation spawns a worker pool of 100 goroutines. Repeated calls in a loop can multiply resource usage. Consider a shared pool or dynamic scaling if performance is a concern.opcua_plugin/server_info.go (1)
40-42: Potential worker oversubscriptionEach parallel
Browsecall starts a pool of 100 workers, possibly leading to hundreds of concurrent goroutines. Consider running them sequentially or unifying them under one task pool if resource constraints become an issue.
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📒 Files selected for processing (5)
opcua_plugin/browse.go(3 hunks)opcua_plugin/browse_frontend.go(1 hunks)opcua_plugin/opcua_opc-plc_test.go(1 hunks)opcua_plugin/opcua_unittest_test.go(8 hunks)opcua_plugin/server_info.go(1 hunks)
🔇 Additional comments (15)
opcua_plugin/browse.go (6)
86-89: Worker pool initializationThis concurrency pattern matches a standard worker-pool approach and appears implemented correctly.
92-98: Initial task schedulingEnqueuing the start node with level 0 is clear and logically sound.
101-108: Graceful shutdown logicClosing
taskChanaftertaskWg.Wait()and then waiting forworkerWgensures an orderly teardown.
222-251: Child task creationThe recursive scheduling of child nodes via
browseChildrenis well-structured and ensures deeper levels can be explored.
399-399: Heartbeat browsingSpawning a separate goroutine for the heartbeat node is consistent with the existing approach. No issues detected.
122-220: Non-blocking send can drop dataUsing a
defaultcase when writing toopcuaBrowserChanmeans data could be discarded if the channel is full. Verify whether dropping node definitions is acceptable. If not, remove thedefaultto block until the channel is available.- select { - case opcuaBrowserChan <- browserDef: - default: - logger.Debugf("Worker %%d: opcuaBrowserChan blocked, skipping", id) - } + opcuaBrowserChan <- browserDefopcua_plugin/browse_frontend.go (1)
44-44: Consistent usage of BrowseInvoking
Browsehere aligns with the refactored concurrency model. No additional concerns apparent.opcua_plugin/opcua_unittest_test.go (7)
106-106: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
133-133: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
171-171: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
211-211: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
251-251: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
294-294: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
695-695: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.opcua_plugin/opcua_opc-plc_test.go (1)
1433-1433: LGTM!The function call has been correctly updated to match the new signature by removing the
levelparameter.
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Actionable comments posted: 0
🧹 Nitpick comments (2)
opcua_plugin/browse.go (2)
77-108: Consider making worker pool size configurable.While the implementation is solid, hardcoding the number of workers and buffer size might not be optimal for all scenarios. Consider making these values configurable based on system resources or user requirements.
-const numWorkers = 100 // Adjust based on your needs +// WorkerPoolConfig holds worker pool configuration +type WorkerPoolConfig struct { + NumWorkers int + BufferSize int +} + +// DefaultWorkerPoolConfig returns default configuration +func DefaultWorkerPoolConfig() WorkerPoolConfig { + return WorkerPoolConfig{ + NumWorkers: 100, + BufferSize: 1000, + } +}
138-142: Consider making max depth configurable.The maximum browse depth is hardcoded to 25 levels. Consider making this configurable to accommodate different OPC UA server hierarchies.
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📒 Files selected for processing (1)
opcua_plugin/browse.go(3 hunks)
⏰ Context from checks skipped due to timeout of 90000ms (1)
- GitHub Check: go-test-opcua-plc
🔇 Additional comments (4)
opcua_plugin/browse.go (4)
65-66: LGTM! Clean wrapper implementation.The public wrapper function is well-documented and correctly implements the new worker pattern interface.
69-75: LGTM! Well-structured task encapsulation.The NodeTask struct effectively encapsulates all necessary parameters for node processing, making the code more maintainable and easier to understand.
234-252: LGTM! Well-implemented helper functions.The helper functions are well-structured with proper error handling and task management. The browseChildren function effectively manages the hierarchical browsing process.
187-193: Verify potential data loss in opcuaBrowserChan.The non-blocking send to opcuaBrowserChan could silently drop nodes if the channel is full. Consider logging metrics about dropped nodes or implementing a backpressure mechanism.
✅ Verification successful
Current implementation of opcuaBrowserChan is appropriate
The non-blocking send with debug logging is an intentional design choice in this worker pool architecture. The implementation:
- Prevents worker deadlocks
- Provides visibility through debug logging
- Operates in a browse context where skipping occasional nodes is preferable to blocking workers
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Search for other instances of opcuaBrowserChan usage to understand the impact rg -A 5 "opcuaBrowserChan.*<-"Length of output: 333
Script:
#!/bin/bash # Find channel declaration and initialization rg -A 2 "opcuaBrowserChan\s*:?=.*chan" # Find consumer/receiver code rg -B 2 "<-\s*opcuaBrowserChan" # Get broader context of browse operation ast-grep --pattern 'func browse($$$) { $$$ }'Length of output: 2739
opcua_plugin/browse.go
Outdated
| return | ||
| } | ||
| // browse uses a worker pool pattern to process nodes | ||
| func browse(ctx context.Context, startNode NodeBrowser, startPath string, logger Logger, parentNodeId string, |
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what happens if someone has multiple "parent nodes"
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@JeremyTheocharis It is handled already inside the constructNodeHierarchy function. As you can see in the image, I have modelled an OPCUA server with a node called Temperature (nodeid= ns=2;i=2) has two parents nodes 1. DMK , 2. Boiler. The Browse operation correctly shows the temperature node then under their corresponding parent nodes.
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Actionable comments posted: 0
🧹 Nitpick comments (7)
opcua_plugin/browse.go (3)
64-68: Enhance function documentation.The function documentation should be expanded to:
- Explain the purpose of each parameter
- Document the worker pool pattern implementation
- Clarify why direct usage should be avoided
70-76: Add field-level documentation to NodeTask struct.Each field in the struct should be documented to explain its purpose and any constraints.
type NodeTask struct { + // node represents the OPC UA node to be processed node NodeBrowser + // path represents the hierarchical path to this node path string + // level represents the current depth in the node hierarchy level int + // parentNodeId represents the ID of the parent node parentNodeId string }
157-281: Consider breaking down the worker function for better maintainability.The worker function handles multiple responsibilities. Consider extracting these into separate functions:
- Node attribute processing
- Node class handling
- Task processing logic
+func processNodeTask(task NodeTask, def *NodeDef) error { + // Extract node attribute processing logic +} +func handleNodeClass(def NodeDef, task NodeTask) error { + // Extract node class handling logic +} func worker( ctx context.Context, id uuid.UUID, // ... other parameters ... ) { // ... existing setup ... for { select { case task, ok := <-taskChan: if !ok { return } - // Current implementation + if err := processNodeTask(task, &def); err != nil { + sendError(ctx, err, errChan, logger) + taskWg.Done() + continue + } + + if err := handleNodeClass(def, task); err != nil { + sendError(ctx, err, errChan, logger) + } } } }opcua_plugin/browse_workers.go (4)
14-14: Correct the spelling in the comment.There's a minor typo in the comment for SampleSize: "requsts" should be "requests".
Apply this diff to fix the typo:
- SampleSize = 5 // Number of requsts to measure response time + SampleSize = 5 // Number of requests to measure response time
56-84: Consider preserving partial history of response times.Currently, the responseTimes slice is cleared after each adjustment, discarding historical data. Retaining a small rolling window (instead of resetting to an empty slice) could improve the stability of your average measurements, preventing abrupt changes.
75-82: Refine debug messages for clarity.Although these debug logs are developer-focused (rather than user-facing error messages), you might consider adding minimal guidance or referencing next steps for developers, e.g., “Consider analyzing network conditions or server load.” This aligns with best practices for actionable logging.
92-101: Optimize the sample buffer handling.The recordResponseTime function discards only the oldest measurement when capacity is reached. For high-throughput systems, consider using a ring buffer or specialized data structure to manage these durations more efficiently and reduce slice overhead.
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📒 Files selected for processing (3)
opcua_plugin/browse.go(4 hunks)opcua_plugin/browse_frontend.go(1 hunks)opcua_plugin/browse_workers.go(1 hunks)
🚧 Files skipped from review as they are similar to previous changes (1)
- opcua_plugin/browse_frontend.go
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opcua_plugin/browse.goopcua_plugin/browse_workers.go
`**/*`: Whenever in a new PR a new function or code is intro...
**/*: Whenever in a new PR a new function or code is introduced, ensure that there is at least somewhere as a code comment, in the README or wherer ever explained the "why" behind the decision. So e.g., why something was preferred over other options, or why a certain loop needs to be executed.
opcua_plugin/browse.goopcua_plugin/browse_workers.go
🔇 Additional comments (5)
opcua_plugin/browse.go (2)
94-96: Address TODO comment about backpressure mechanism.The current implementation uses a large buffer to avoid blocking, but this might lead to memory issues under high load. Consider implementing a backpressure mechanism using:
- A semaphore to limit concurrent tasks
- A sliding window approach
- Rate limiting based on server response times
Would you like me to propose a backpressure implementation?
283-323: LGTM! Well-documented helper functions.The helper functions are well-implemented with:
- Clear documentation
- Proper error handling
- Good separation of concerns
opcua_plugin/browse_workers.go (3)
18-25: Explain the rationale behind ServerMetrics.This newly introduced struct benefits from a brief explanation of “why” the worker-based concurrency approach is chosen, along with any design tradeoffs or alternatives considered. Such context helps maintainers and contributors understand the long-term maintainability and reasoning behind collecting these metrics.
Would you like to add a code comment or README snippet explaining your decision to implement ServerMetrics?
36-44: Verify behavior when adding a worker with an existing ID.The addWorker method overwrites the stop channel if the given ID already exists in the map, potentially leading to a stale channel or worker confusion. Consider checking for an existing entry before overwriting.
45-54: Removal logic looks good.The removeWorker function correctly closes the associated channel and removes it from the map, preventing potential leaks. No changes needed.
Description
Benchmark results for the old recursive approach
Benchmark results for the new worker pattern
Summary by CodeRabbit
Summary by CodeRabbit
Refactor
levelparameter from theBrowsefunction.NodeTasktype for better node management.ServerMetricsstruct for monitoring OPCUA server performance.Bug Fixes
Chores
browsefunction toBrowsefor consistency.