Go’s standard library provides everything needed to generate RSA key pairs and save them in PEM format. Here are the essential packages: crypto/rsa — Implements RSA encryption per PKCS #1 and RFC 8017. The GenerateKey() function creates a keypair of specified bit size. crypto/rand — Provides Reader, a cryptographically secure random source. On Linux, it…
Hyperledger Fabric is a modular, enterprise-grade consortium blockchain platform. While its official documentation is comprehensive, deploying a test network from scratch requires configuring multiple dependencies and tools—a process that’s time-consuming for new users. This guide covers both automated and manual setup approaches to get a working Fabric network running quickly. Prerequisites You’ll need: Ubuntu 24.04…
When you need a specific Go version on Ubuntu, the default package manager often lags behind. Production systems like Kubernetes, Hyperledger Fabric, and other projects frequently require versions newer than what’s available in standard repositories. This guide covers system-level installation that allows multiple versions to coexist. Remove existing Go installations Start by cleaning up any…
Go doesn’t have a dedicated FileExists() function. Instead, use os.Stat() to retrieve file metadata and inspect the error type to determine what actually happened. Basic File Existence Check import “os” func fileExists(path string) bool { _, err := os.Stat(path) return !os.IsNotExist(err) } os.Stat() returns an error only if something goes wrong. The key is using…
Go’s net/http package provides straightforward methods for sending POST requests. The two main approaches are Post() for raw body content and PostForm() for URL-encoded form data. Using PostForm for Form Data PostForm() handles URL-encoded form submissions automatically, setting the Content-Type header to application/x-www-form-urlencoded: package main import ( “io” “net/http” “net/url” ) func main() { data…
Go provides straightforward ways to write to standard output and standard error streams. Understanding when and how to use each is essential for building robust applications, especially in containerized and cloud environments where log separation matters. Using the fmt Package The fmt package is the most common approach for printing to STDOUT: package main import…
Getting a process’s parent process ID (PPID) is useful for monitoring, debugging, and process management tasks. Go provides straightforward ways to access this information across different platforms. Using the os Package The simplest approach is the os package, which works on Unix-like systems: package main import ( “fmt” “os” ) func main() { ppid :=…
The standard way to get your running process’s PID in Go is through the os package: package main import ( “fmt” “os” ) func main() { pid := os.Getpid() fmt.Println(“Current PID:”, pid) } os.Getpid() returns an int representing the current process’s ID. This works across all platforms—Linux, macOS, Windows, and others. Getting the Parent Process…
Go’s os package provides a straightforward function to retrieve the system’s hostname: package main import ( “fmt” “os” ) func main() { hostname, err := os.Hostname() if err != nil { fmt.Println(“Error:”, err) return } fmt.Println(“Hostname:”, hostname) } The os.Hostname() function returns a string containing the hostname and an error value. Always check the error—it…
Getting the current epoch timestamp is straightforward using the time package: package main import ( “fmt” “time” ) func main() { epoch := time.Now().Unix() fmt.Println(epoch) } The time.Now().Unix() call returns the number of seconds since January 1, 1970 UTC as an int64. Getting nanosecond precision If you need higher resolution, use UnixNano() for nanoseconds since…
Go compiles quickly and go run handles small scripts, but a REPL is more practical for interactive testing and exploration. Here are the best options available today. gore gore remains the most mature Go REPL. It’s actively maintained and handles most interactive development workflows. Install it: go install github.com/motemen/gore/cmd/gore@latest Basic usage: $ gore gore version…
Use os.Getenv() to read an environment variable: package main import ( “fmt” “os” ) func main() { val := os.Getenv(“MY_VAR”) fmt.Println(val) } os.Getenv() returns an empty string if the variable doesn’t exist. This means you can’t distinguish between an unset variable and one explicitly set to an empty string. Checking if a variable exists To…
Go’s io.Reader interface is fundamental to working with streams of data. When you have a byte slice and need to pass it to a function expecting an io.Reader, the standard library provides straightforward solutions. Using bytes.NewReader The most direct approach is bytes.NewReader(), which wraps a byte slice in an io.Reader: package main import ( “bytes”…
The most straightforward approach is using ioutil.ReadFile() or the modern os.ReadFile() function, both of which return the entire file content as a byte slice that you can convert to a string. package main import ( “fmt” “os” ) func main() { content, err := os.ReadFile(“example.txt”) if err != nil { fmt.Println(“Error reading file:”, err) return…
In Go, a string is a read-only slice of bytes, while a rune is an alias for int32 representing a Unicode code point. Understanding this distinction is essential when you need to work with individual characters, especially in multilingual text. Basic Conversion The simplest approach is direct type conversion: s := “Hello, 世界” runes :=…
Sending output to stderr keeps error messages separate from normal program output, making it easier to redirect and filter logs in shell scripts and pipelines. Basic Approach with fmt The simplest method uses fmt.Fprintln() with os.Stderr: package main import ( “fmt” “os” ) func main() { fmt.Fprintln(os.Stderr, “This is an error message”) } This writes…
Error handling is fundamental to Go development. Often you’ll need to convert an error to a string for logging, displaying to users, or including in API responses. Go provides several straightforward approaches. Using the Error() Method Every error in Go implements the error interface, which has a single method: Error() string. The simplest conversion is…
Processing files line by line is a common task in Go. Here are the practical approaches, from simplest to most flexible. Using bufio.Scanner The most straightforward method uses bufio.Scanner, which handles line splitting automatically: package main import ( “bufio” “fmt” “log” “os” ) func main() { file, err := os.Open(“input.txt”) if err != nil {…
Many Go functions accept an io.Reader interface. To pass a string to these functions, use strings.NewReader, which wraps the string without copying it—the data is read directly from the original string. Basic Usage import “strings” reader := strings.NewReader(“Hello, World!”) This creates an io.Reader that can be passed to any function expecting that interface. The reader…