Category Archives: golang
Forward multiple kubernetes pods for local development
kubefwd is a great tool that can forward a lot of pods at once to your local machine. The only downside for me is that it touches your local /etc/hosts. That’s how I use it:
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sudo KUBECONFIG=<path to your k8s config> kubefwd svc -l "app in (first-api, second-api, third-service)" |
It does not have huge documentation, but it is written in golang, and you can check how the source …
Force ipv4 for golang http client
Sometimes you want to prevent your http client from using ipv6/tcp6. That’s how you do it.
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dialer := &net.Dialer{ Timeout: dialTimeout, KeepAlive: keepAliveTimeout, } transport := &http.Transport{ Proxy: http.ProxyFromEnvironment, ForceAttemptHTTP2: false, DialContext: func(ctx context.Context, network string, addr string) (net.Conn, error) { ipv4, err := resolveIPv4(addr) if err != nil { return nil, err } return dialer.DialContext(ctx, network, ipv4) }, } httpClient := &http.Client{ Transport: transport, Timeout: args.HTTPTimeout, } // resolveIPv4 resolves an address to IPv4 address. func resolveIPv4(addr string) (string, error) { url := strings.Split(addr, ":") m := new(dns.Msg) m.SetQuestion(dns.Fqdn(url[0]), dns.TypeA) m.RecursionDesired = true config, _ := dns.ClientConfigFromFile("/etc/resolv.conf") c := new(dns.Client) r, _, err := c.Exchange(m, net.JoinHostPort(config.Servers[0], config.Port)) if err != nil { return "", err } for _, ans := range r.Answer { if a, ok := ans.(*dns.A); ok { url[0] = a.A.String() } } return strings.Join(url, ":"), nil } |
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
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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:
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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 …
«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
Go library for creating slack bots
You can use it like that:
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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