How does Go handle cyclic dependencies between packages?
- Go does not support cyclic dependencies between packages.
- Go resolves cyclic dependencies by using package initialization.
- Go resolves cyclic dependencies by using the 'import' keyword.
- Go resolves cyclic dependencies by using the 'require' keyword.
In Go, cyclic dependencies between packages are handled through package initialization. When a package is imported, its init function is called, allowing initialization code to execute before the package is used. This mechanism helps manage cyclic dependencies effectively.
The '_______' function in Go is used to regain control of a panicking goroutine.
- capture
- defer
- panic
- recover
The recover function in Go is used to regain control of a panicking goroutine. It's typically used in deferred functions to handle panics gracefully and to resume normal execution.
What are some strategies for error handling and recovery within middleware functions in Go?
- Automatically recovering from panics using the recover function.
- Ignoring errors and continuing execution.
- Logging errors, returning an error response, or passing the error to the next middleware.
- Redirecting to an error page or sending an email notification.
Error handling and recovery within middleware functions in Go typically involve logging errors, returning an appropriate error response to the client, or passing the error to the next middleware in the chain. These strategies ensure that errors are properly handled and do not cause unexpected behavior in the application. Additionally, using the recover function can help recover from panics and prevent the entire application from crashing, although it should be used judiciously and only for handling exceptional cases.
Your team is transitioning from a monolithic architecture to microservices, and each service has its own database schema. How would you coordinate database migrations across multiple services to maintain data consistency and minimize downtime?
- Adopt a shared-nothing architecture to isolate database instances for each microservice
- Assign each microservice team the responsibility of managing its database migrations
- Implement a centralized database migration service that coordinates schema changes across all microservices
- Use distributed transactions to synchronize schema changes across microservices
Assigning each microservice team the responsibility of managing its database migrations ensures that changes are aligned with the service's requirements and reduces coordination overhead. Implementing a centralized database migration service might introduce a single point of failure and increase complexity. Distributed transactions can lead to performance issues and tightly couple microservices. Adopting a shared-nothing architecture might provide isolation but doesn't inherently address coordination of schema changes and can increase operational complexity.
Which testing framework in Go provides support for table-driven tests, allowing multiple test cases to be defined in a structured format?
- Ginkgo
- GoConvey
- Testify
- Testify and Ginkgo
Ginkgo is a popular testing framework in Go that offers support for table-driven tests, which allow multiple test cases to be defined in a structured format. This approach enhances test readability and maintenance by separating test cases into clear tables.
MongoDB uses _______ for defining indexes to improve query performance.
- AVL trees
- B-trees
- Binary Search Trees
- Hashing
MongoDB primarily uses B-trees (balanced trees) for indexing. B-trees are well-suited for disk-based storage systems and efficiently support range queries and updates, enhancing query performance.
What does the '<<' operator do in Go when used with integers?
- Divides two integers
- Left shifts the bits of an integer
- Multiplies two integers
- Right shifts the bits of an integer
In Go, the '<<' operator performs a left shift operation on the bits of an integer. It moves each bit to the left by a specified number of positions, effectively multiplying the integer by 2 raised to the power of the shift count.
Explain the concept of capacity and length in slices in Go.
- Capacity and length both represent the maximum number of elements a slice can hold.
- Capacity is the number of elements in the slice and length is the maximum number of elements it can hold.
- Length is the number of elements in the slice and capacity is the maximum number of elements it can hold.
- Length represents the maximum number of elements a slice can hold and capacity represents the number of elements in the slice.
In Go, the length of a slice is the number of elements it contains, and the capacity of a slice is the number of elements in the underlying array, counting from the first element in the slice. The length of a slice can change during execution, but the capacity of a slice remains fixed. Understanding the difference between length and capacity is crucial for efficient memory management in Go programs.
You're developing a web application in Go, and you need to execute a SQL query that might return multiple rows. Which method from the database/sql package would you use, and how would you handle the returned rows?
- Exec method; Execute the query and retrieve the result set directly. Use rows.Scan() within a loop to scan each row into variables for processing.
- Prepare method; Prepare the SQL statement, execute it using Query or QueryRow, then scan each row using rows.Scan().
- Query method; Use rows.Next() in a loop to fetch each row one by one, then process each row's data.
- QueryRows method; Iterate over the rows using a loop and scan each row into a struct to process the data.
The correct method to use in this scenario is QueryRows. This method allows executing a SQL query that returns multiple rows. You can iterate over the rows using a loop and scan each row into a struct or variables for further processing.
You're writing unit tests for a function that should return an error under certain conditions. How would you test this behavior in Go?
- Check if the error returned is not nil
- Compare the returned error message to an expected error message
- Use the testing.T.Error function to fail the test if the error is not returned
- Use the testing.T.FailNow function to immediately fail the test
In Go, you can test error conditions by comparing the returned error message to an expected error message. This ensures that the function under test behaves as expected when encountering specific error conditions. Simply checking if the error returned is not nil may not provide enough information about the nature of the error. Similarly, using testing.T.Error only reports an error but doesn't validate the specific error returned. Using testing.T.FailNow immediately stops the test, which might not allow you to collect all the error information. Therefore, comparing the returned error message to an expected error message is the most appropriate approach.