[PLA-2013] Add config and LRU cache

[leonardocustodio]

PR Type

Enhancement, Configuration changes

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Description

• Implemented LRU caching for metadata in chain_info.dart to optimize memory usage.
• Added logging capabilities across the application to track metadata instantiation and request handling.
• Introduced environment variable support for server configuration, including number of isolates and bind port.
• Updated dependencies to include lru_memory_cache, dotenv, and logging.
• Provided an example .env file for configuration guidance.

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Changes walkthrough 📝

	Relevant files
Enhancement	chain_info.dart Implement LRU caching and logging for chain metadata          lib/decoder/chain_info.dart Introduced LRU caching for metadata to optimize memory usage. Added environment variable support for configuration. Implemented logging for metadata instantiation. +42/-38  general.dart Add logging for request handling and errors                            lib/handler/general.dart Added logging for request handling and error scenarios. Configured logger to capture all log levels. +14/-0
Configuration changes	server.dart Load server configuration from environment variables          bin/server.dart Added configuration loading from environment variables. Implemented logging for server startup parameters. +34/-3    .env.example Provide example environment configuration file                      .env.example Added example environment variables for configuration. +4/-0
Dependencies	pubspec.yaml Update dependencies and project version                                    pubspec.yaml Updated project version to 2.1.0. Added new dependencies: lru_memory_cache, dotenv, and logging. +8/-2
Additional files (token-limit)	v1032.dart ...                                                                                                            lib/consts/enjin/production/v1032.dart ... +3/-2

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[github-actions]

PR Reviewer Guide 🔍

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Key issues to review Error Handling The implementation of getDecodedMetadata and getChainInfo lacks error handling for potential exceptions from MetadataDecoder.instance.decode. Consider adding try-catch blocks or other error handling mechanisms to manage exceptions and provide fallbacks or error messages. Logging Configuration The logger is configured globally in multiple files which might lead to redundant configurations and potential conflicts. Consider centralizing the logger configuration to ensure consistency across different parts of the application. Configuration Duplication There is a duplication in the configuration loading logic in bin/server.dart and lib/decoder/chain_info.dart. It's better to have a single point of configuration loading to avoid inconsistencies and make the code easier to maintain.

[github-actions]

PR Code Suggestions ✨

Category	Suggestion	Score
Possible bug	Add checks to ensure metadata fields exist before accessing them To ensure that the cache key generation is robust and less error-prone, consider adding null checks or assertions to ensure that the necessary fields exist in the metadata before accessing them. This change prevents potential runtime errors due to missing fields. lib/decoder/chain_info.dart [18-19] -generateKey: (k) => - "${k.constants['System']!['Version']!.value['spec_name']}-${k.constants['System']!['Version']!.value['spec_version']}", +generateKey: (k) { + assert(k.constants['System'] != null && k.constants['System']!['Version'] != null, 'Required metadata fields are missing'); + return "${k.constants['System']!['Version']!.value['spec_name']}-${k.constants['System']!['Version']!.value['spec_version']}"; +}, Suggestion importance[1-10]: 9 Why: Adding assertions to check for the existence of necessary fields before accessing them is crucial for preventing runtime errors, making this a high-impact suggestion for improving code robustness.	9
Maintainability	Use constants for default values to improve maintainability To enhance code maintainability and avoid magic numbers, consider defining constants for default values used in parsing environment variables. This approach not only makes the code cleaner but also centralizes the configuration values, making them easier to manage. bin/server.dart [17-20] +const defaultNumberOfIsolates = 8; +const defaultBindPortNumber = 8090; numberOfIsolates = - int.tryParse(env.getOrElse('NUMBER_OF_ISOLATES', () => '8')) ?? 8; + int.tryParse(env.getOrElse('NUMBER_OF_ISOLATES', () => defaultNumberOfIsolates.toString())) ?? defaultNumberOfIsolates; defaultBindPort = - int.tryParse(env.getOrElse('DEFAULT_BIND_PORT', () => '8090')) ?? 8090; + int.tryParse(env.getOrElse('DEFAULT_BIND_PORT', () => defaultBindPortNumber.toString())) ?? defaultBindPortNumber; Suggestion importance[1-10]: 8 Why: Using constants for default values improves maintainability by centralizing configuration values, making the code cleaner and easier to manage. This is a good practice for reducing potential errors.	8
Performance	Cache decoded metadata to reduce computational overhead To improve the efficiency of the getChainInfo function, consider caching the result of getDecodedMetadata directly, rather than decoding it each time a cache miss occurs. This modification can significantly reduce the computational overhead, especially for frequently accessed data. lib/decoder/chain_info.dart [50-55] if (chainInfo == null) { logger.info("Metadata $network v$specVersion instantiated"); - final metadata = getDecodedMetadata(network, specVersion); + final metadata = cache.getOrAdd(getSpecName(network, specVersion), () => MetadataDecoder.instance.decode(getDecodedMetadata(network, specVersion))); chainInfo = ChainInfo.fromMetadata(metadata); } Suggestion importance[1-10]: 8 Why: Caching the decoded metadata directly can significantly reduce computational overhead, enhancing performance for frequently accessed data. This is a valuable optimization for improving efficiency.	8
Best practice	Improve variable naming for clarity and explicitness Consider using a more descriptive variable name for specPerIsolate and specExpireDuration to indicate their units. For example, specPerIsolate could be renamed to specsPerIsolate to clarify that it represents the number of specs per isolate, and specExpireDuration could be renamed to specExpireDurationSeconds to explicitly state the unit of time. bin/server.dart [21-24] -int specPerIsolate = +int specsPerIsolate = int.tryParse(env.getOrElse('SPEC_PER_ISOLATE', () => '4')) ?? 4; -int specExpireDuration = +int specExpireDurationSeconds = int.tryParse(env.getOrElse('SPEC_EXPIRE_DURATION', () => '300')) ?? 300; Suggestion importance[1-10]: 7 Why: The suggestion improves code readability by making variable names more descriptive, which helps in understanding the code better. However, it is not a critical change.	7