architecture overview⁂

this document provides an in-depth look at the architecture of the openai summarize diff action, designed for developers who want to understand or contribute to the codebase.

overview⁂

the openai summarize diff action is designed to:

1. receive a git diff as input
2. send the diff to openai's api for analysis
3. return a human-readable explanation of the changes

the architecture follows a modular design with clear separation of concerns.

components⁂

core components⁂

• action entry point (src/index.js): coordinates the overall workflow
• openai client (src/openai.js): manages interactions with the openai api
• diff processing (src/diff.js): handles parsing and preprocessing of git diffs
• error handling (src/errors.js): provides standardized error handling

data flow⁂

1. the github action is triggered and inputs are collected
2. inputs are validated
3. the openai client is initialized
4. the diff is preprocessed (e.g., trimmed if too large)
5. the diff is sent to openai with a carefully crafted prompt
6. the explanation is received from openai
7. the explanation is processed and returned as an output

design decisions⁂

prompt engineering⁂

the action uses a specific prompting strategy to get high-quality explanations:

const systemMessage = `You are an expert developer tasked with explaining code changes in a clear, 
concise manner. Analyze the following git diff and provide a human-readable explanation 
of what has changed and why it might have been changed.`;

const userMessage = `Please explain this diff in ${maxCharacters} characters or less:
\`\`\`
${diff}
\`\`\`

Example of a good explanation format:
"${examplePostSummary}"`;

error handling strategy⁂

the action implements robust error handling with exponential backoff for api calls:

async function callWithRetry(fn, maxRetries = 3, initialDelay = 1000) {
  let retries = 0;

  while (true) {
    try {
      return await fn();
    } catch (error) {
      if (retries >= maxRetries || !isRetryableError(error)) {
        throw error;
      }

      const delay = initialDelay * Math.pow(2, retries);
      console.log(`Retry ${retries + 1}/${maxRetries} after ${delay}ms`);
      await new Promise(resolve => setTimeout(resolve, delay));
      retries++;
    }
  }
}

testing strategy⁂

the project follows a comprehensive testing strategy:

1. unit tests: test individual functions in isolation
2. integration tests: test interactions between components
3. e2e tests: test the entire action workflow

performance considerations⁂

several optimizations are made to ensure efficient operation:

1. diff preprocessing: large diffs are trimmed to avoid token limits
2. output formatting: the output is designed to be concise but informative
3. caching: frequently used operations are cached

future architecture considerations⁂

potential future enhancements to the architecture:

1. support for different openai models
2. more sophisticated diff preprocessing
3. enhanced customization options for the output format

dependency graph⁂

action.yml
└── src/index.js
    ├── src/openai.js
    │   └── openai (external)
    ├── src/diff.js
    └── src/errors.js

configuration flow⁂

the action's behavior can be configured through several inputs:

1. diff: the git diff to be explained (required)
2. apikey: the openai api key (required)
3. examplePostSummary: example of a good summary (optional)
4. maxTokens: maximum tokens for the openai response (optional)
5. maxCharacters: maximum characters in the output (optional)

code organization⁂

the code follows a modular organization:

src/
├── index.js       # Main entry point and workflow coordination
├── openai.js      # OpenAI API client and interaction logic
├── diff.js        # Diff parsing and preprocessing utilities
└── errors.js      # Error types and handling utilities

each module has a single responsibility, making the code easier to maintain and extend.