Category Archives: golang

Install go2 beta on MacOS

A quick guide on installing golang v2 development revision. It works for my MacOS Big Sur (with an Intel processor).

Using DataDog on your CentOs

DD_AGENT_MAJOR_VERSION=7 DD_API_KEY=<your-key> DD_SITE="datadoghq.eu" bash -c "$(curl -L https://s3.amazonaws.com/dd-agent/scripts/install_script.sh)"

sudo nano /etc/datadog-agent/datadog.yaml
# uncomment logs_enabled: true
sudo systemctl restart datadog-agent
sudo mkdir /etc/datadog-agent/conf.d/go.d
sudo nano /etc/datadog-agent/conf.d/go.d/conf.yaml
# and add contents from the url below

DD_AGENT_MAJOR_VERSION=7 DD_API_KEY=<your-key> DD_SITE="datadoghq.eu" bash -c "$(curl -L https://s3.amazonaws.com/dd-agent/scripts/install_script.sh)"

sudo nano /etc/datadog-agent/datadog.yaml

# uncomment logs_enabled: true

sudo systemctl restart datadog-agent

sudo mkdir /etc/datadog-agent/conf.d/go.d

sudo nano /etc/datadog-agent/conf.d/go.d/conf.yaml

# and add contents from the url below

https://app.datadoghq.eu/logs/onboarding/server https://docs.datadoghq.com/agent/faq/error-restarting-agent-already-listening-on-a-configured-port/ Or, if you want a dockerized version of DataDog agent, and you want to listen to docker logs, you can do this:

docker run -d --name datadog-agent \
           -e DD_API_KEY=<DATADOG_API_KEY> \
           -e DD_LOGS_ENABLED=true \
           -e DD_LOGS_CONFIG_CONTAINER_COLLECT_ALL=true \
           -e DD_CONTAINER_EXCLUDE_LOGS="name:datadog-agent" \
           -e DD_SITE="datadoghq.eu"  \
           -v /var/run/docker.sock:/var/run/docker.sock:ro \
           -v /proc/:/host/proc/:ro \
           -v /opt/datadog-agent/run:/opt/datadog-agent/run:rw \
           -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro \
           datadog/agent:latest

docker run -d --name datadog-agent \

-e DD_API_KEY=<DATADOG_API_KEY> \

-e DD_LOGS_ENABLED=true \

-e DD_LOGS_CONFIG_CONTAINER_COLLECT_ALL=true \

-e DD_CONTAINER_EXCLUDE_LOGS="name:datadog-agent" \

-e DD_SITE="datadoghq.eu" \

-v /var/run/docker.sock:/var/run/docker.sock:ro \

-v /proc/:/host/proc/:ro \

-v /opt/datadog-agent/run:/opt/datadog-agent/run:rw \

-v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro \

datadog/agent:latest

More info here — https://docs.datadoghq.com/agent/docker/log/?tab=containerinstallation Then you will see your logs here — https://app.datadoghq.eu/logs

Install go with gvm on MacOS Big Sur

I used to use gvm for this — https://github.com/moovweb/gvm. But initial installation of go from scratch does not work for Big Sur as 1.4 does not have a binary for this OS (this command fails — gvm install go1.4 -B). To use gvm, you can do this: 0. Install gvm — bash <

Complete list of swagger options to protobuf file

Here is an example with many options that help generate proper swagger out of protofile. Original URL — https://raw.githubusercontent.com/grpc-ecosystem/grpc-gateway/master/examples/internal/proto/examplepb/a_bit_of_everything.proto.

Refactor your code and know it’s completely backward compatible

The idea is to run 2 versions of code on production: 1 (control group) — is your old implementation which will be returned to the end user 2 (the experiment) — is a new implementation which results will be checked against the control group and logged It will be run asynchronously and only for a …

GRPC fallback to Rest API with custom field names

When you generate JSON for Rest API from proto-file, protoc-gen-gofast generates field names for JSON in lowerCamelCase format while most of the Rest APIs use snake_case for that. And if you want to replace some legacy API with your new implementation without breaking backward compatibility, you need to fix it. There could be different ways …

Integration tests with testcontainers-go

Here is the go library that simplifies integration tests with docker containers — https://github.com/testcontainers/testcontainers-go. That’s how you can use it to test sql — https://github.com/testcontainers/testcontainers-go/blob/master/docs/examples/cockroachdb.md. Project documentation — https://golang.testcontainers.org/features/docker_compose/ The idea is to prepare the environment, build your app, then make requests and check the DB state.

«Awesome go» resources

A list of good resources for each go specific part — https://github.com/avelino/awesome-go. A list of good tools for go performance or just fast libs — https://github.com/cristaloleg/awesome-go-perf Security lists — https://github.com/guardrailsio/awesome-golang-security, https://github.com/Binject/awesome-go-security

Go library for creating slack bots

You can use it like that:

package main

import (
	"context"
	"github.com/shomali11/slacker"
	"log"
)

func main() {
	bot := slacker.NewClient("<YOUR SLACK BOT TOKEN>")

	definition := &slacker.CommandDefinition{
		Handler: func(request slacker.Request, response slacker.ResponseWriter) {
			response.Reply("pong")
		},
	}

	bot.Command("ping", definition)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	err := bot.Listen(ctx)
	if err != nil {
		log.Fatal(err)
	}
}

package main

import (

"context"

"github.com/shomali11/slacker"

"log"

)

func main() {

bot := slacker.NewClient("<YOUR SLACK BOT TOKEN>")

definition := &slacker.CommandDefinition{

Handler: func(request slacker.Request, response slacker.ResponseWriter) {

response.Reply("pong")

}

bot.Command("ping", definition)

ctx, cancel := context.WithCancel(context.Background())

defer cancel()

err := bot.Listen(ctx)

if err != nil {

log.Fatal(err)

}

https://github.com/shomali11/slacker

How to work with core dumps of Go programs

If you want to check what is going on in your service during load (on production or during stress testing process), you can take a core dump of your app and load it into Goland for further debugging.

# first you need to get your app's PID
ps aux|grep <your-app-bin-name> 
gcore <PID>
# download dump file and binary file to a local machine with
kubectl cp <some-namespace>/<some-pod>:/core.<PID> ~/Downloads
kubectl cp <some-namespace>/<some-pod>:<your-app-bin-path> ~/Downloads

# first you need to get your app's PID

ps aux|grep <your-app-bin-name>

gcore <PID>

# download dump file and binary file to a local machine with

kubectl cp <some-namespace>/<some-pod>:/core.<PID> ~/Downloads

kubectl cp <some-namespace>/<some-pod>:<your-app-bin-path> ~/Downloads

Then open it your Goland: Navigate to Run | Open Core Dump. In the Executable field, …