How to use the command gops (with examples)

The gops command is a tool that allows you to list and diagnose Go processes currently running on your system. It provides various useful functionalities for troubleshooting and monitoring Go programs. In this article, we will explore each of the use cases of the gops command with examples.

Use case 1: Print all go processes running locally

Code:

gops

Motivation:

The motivation for using this example is to quickly view all the Go processes running on the local system. It is useful for verifying if the Go programs are running as expected and to identify any potential issues.

Explanation:

The gops command without any arguments lists all the Go processes running on the local system. It gives an overview of the process ID (PID), the call name, the program name, and the start time of each process.

Example output:

PID     NAME              COMMAND
123     example-app       /path/to/example-app
456     another-app       /path/to/another-app
789     hello-world       /path/to/hello-world

Use case 2: Print more information about a process

Code:

gops pid

Motivation:

The motivation for using this example is to obtain detailed information about a specific Go process. By providing the process ID as an argument, we can gather insights into the program, including the version, the start time, the working directory, and other details.

Explanation:

The gops command with a process ID (pid) as an argument prints detailed information about a specific Go process. The process ID can be obtained from the output of the gops command without any arguments.

Example output:

NAME:       example-app
PID:        123
VERSION:    go1.X.X
START:      2022-01-01 00:00:00
UPTIME:     2h10m6s
WORKDIR:    /path/to/example-app
...

Use case 3: Display a process tree

Code:

gops tree

Motivation:

The motivation for using this example is to visualize the process hierarchy of the Go programs running on the system. It helps in understanding the relationship between parent and child processes, allowing for further investigation or identification of potential performance bottlenecks.

Explanation:

The gops tree command displays a process tree, depicting the hierarchical relationship between Go processes. It provides insights into the child and parent processes, helping to understand the execution flow and dependencies.

Example output:

example-app (123)
├── goroutine1 (456)
│   ├── goroutine1.1 (789)
└── goroutine2 (012)

Use case 4: Print the current stack trace from a target program

Code:

gops stack pid|addr

Motivation:

The motivation for using this example is to obtain a current stack trace from a target Go program. By providing either the process ID (pid) or the address (addr) of the target program, we can diagnose any issues, such as deadlocks or inefficiencies.

Explanation:

The gops stack command with an argument of either process ID (pid) or address (addr) prints the current stack trace from a target Go program. The process ID or address can be obtained from the output of the gops command without any arguments.

Example output:

goroutine 1 [running]:
main.myGoroutine()
/path/to/example-app/main.go:10 +0xf0
created by main.main
/path/to/example-app/main.go:6 +0x20

Use case 5: Print the current runtime memory statistics

Code:

gops memstats pid|addr

Motivation:

The motivation for using this example is to retrieve the current runtime memory statistics of a specific Go program. By providing either the process ID (pid) or the address (addr) of the target program, we can monitor memory usage and identify any memory-related issues.

Explanation:

The gops memstats command with an argument of either process ID (pid) or address (addr) prints the current runtime memory statistics of a Go program. It provides information on the heap and stack allocations, garbage collection details, and other memory-related metrics.

Example output:

Alloc        = 12345678
TotalAlloc   = 23456789
Sys          = 34567890
...

Conclusion

The gops command is a versatile tool for managing and diagnosing Go processes. By utilizing various use cases provided by this command, you can effectively monitor, debug, and optimize your Go programs. Experiment with these examples to gain insights into the Go processes running on your system and enhance your development and troubleshooting experience.