370 lines
11 KiB
Markdown
370 lines
11 KiB
Markdown
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---
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title: "iex and dbg/1 without pry prompts"
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date: "2024-06-06"
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draft: true
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---
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A lot of folks have been pitting Go and Rust against each other. Normally, I
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would abstain from throwing my opinion out on the internet, but it's come up at
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work and since I heavily prefer one over the other (Rust subjectively!), I want
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to write out why that is. Hopefully it is useful to others out there.
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<!--more-->
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# Rust versus Golang
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I'm aiming to keep this succinct so the people I share this with will actually
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read it. This will probably be dense and pointed, as I'm trying to construct an
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argument.
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This article is opinion and not stating objective fact. These are my
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preferences. I have roughly-equivalent Rust experience, exposure, and knowledge
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than I do Golang, though I have run, operated, and maintained far more Golang
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services at my job than I have Rust.
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Also by posting this I'm sure I will get free consultancy on my Go code and help
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me be a better programmer! 😜
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## Stop Comparing! They're Different!
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Of course they are! This doesn't mean they can't be used to solve the same
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problems. In my experience, one is simply better than the other for the same
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use-cases.
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# Why Rust
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## Rust has _all_ of Go's superpowers
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### Goroutines
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Use `tokio::spawn`. Yes, they are different (mainly stackless versus
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stackful) but the goal and considerations are effectively the same.
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### Channels
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Use `std::sync::mpsc`.
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### Defer
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Largely unnecessary thanks to the compiler, but you can implement your
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own via the `Drop` trait or reach for `scopeguard`.
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### Tooling
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Again, Rust has an incredible tools ecosystem just like Go. Better in many ways
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since many tools considered "necessary" for modern and idiomatic Go are simply
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are not so for Rust, such as code generation. Such needs are instead fulfilled
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by metaprogramming (macros).
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### Explicit error handling
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Hahaha!
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You're gonna _love_ Rust in comparison.
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## Rust is expressive
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Being expressive has downsides. A common question I'll find myself asking is
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"Which of these four ways is the _best_ way to do this?"
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But I would rather be able to have the expressions in the code mirror the intent
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_more_ than be stuck with Go's simplicity.
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## Rust code has fewer bugs
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Obviously this is factually incorrect. However, I simply write my code in Rust
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and when it compiles it works as I intended. Rust code and the compiler make it
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much more difficult to represent invalid states.
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Meanwhile Go code has nil checks, pointers, implicit interfaces, and a few other
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things you will inevitably run into.
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That said, Go's tooling has been improving a _lot_ around this in my opinion;
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`golangci-lint` is awesome.
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## Inline tests
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I strongly dislike being required to put my unit tests in separate files. Call
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me crazy, but having the tests in the same file is something I find appealing.
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## Modules and dependencies
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Go's module system got bolted on a little late and suffers from the Google
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monorepo assumptions/expectations situation. In some ways, this is actually
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very cool. In many ways, though, it's pretty annoying.
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Rust has its own issues with Cargo and its ties to GitHub, but even those can be
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worked around if you like.
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Rust also has issues with MSRV "promises" being largely unenforceable due to
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Cargo lockfiles not being `--locked` by default. This is pretty mind-boggling
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to me. Could also be a skill issue.
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## Documentation
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Rust's standard library and popular crates' documentation is _generally_ much
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better than Go's. Doctests and examples are common.
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## Macros
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Having them is better than not. They are awesome. Yes, they make the compiler
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slower. Yes, they can do awful stuff.
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So does Go codegen.
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## No surprises
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Nothing that executes before `main()` while Go has freakin' `init()` and of
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course you can instantiate literally anything globally.
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In Rust, you don't have this, which sucks and means you do `OnceLock`/
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`OnceCell`/`lazy_static!` instead and it can be painful if you're so dead set on
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doing something weird like that.
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But I'll take no surprises and explicitness any day.
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## Examples
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I wanted to include a number of code examples I found particularly
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Rust-favoring. A picture is worth a thousand words!
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### Obvious: Error Handling
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This is a simplified function in production right now:
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```go
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func (t *Bot) FinishReceivingRequest(req RequestInProgress) (result *Request, err error) {
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result.Data = req.Data
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assignee, err := t.GetAssigneeSlackUser(req)
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if err != nil {
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return nil, fmt.Errorf("failed to retrieve assignee's Slack user info: %w", err)
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}
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result.SlackAssigneeID = assignee.ID
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manager, err := t.Slack.GetUserManager(assignee.ID)
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if err != nil {
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return nil, fmt.Errorf("failed to retrieve the assignee's manager Slack user info: %w", err)
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}
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result.SlackAssigneeMgrID = manager.ID
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issueSkeleton, err := req.Data.BuildJiraIssue(t, req)
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if err != nil {
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return nil, logrus.Errorf("Failed to create Jira issue object: %+v", err)
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}
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issue, res, err := t.Jira.CreateIssue(issueSkeleton)
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defer res.Body.Close()
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if err != nil {
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_, _, err := t.Slack.PostMessage(t.Conf.Slack.Channels.RequestThreads,
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slack.MsgOptionDisableLinkUnfurl(),
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slack.MsgOptionBlocks(
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slack.NewSectionBlock(
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&slack.TextBlockObject{
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Type: "mrkdwn",
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Text: "I failed to create a Jira ticket. See logs for details.\n\nError: " + err.Error(),
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}, nil, nil,
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),
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),
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)
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if err != nil {
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logrus.Errorf("failed to send Jira ticket creation failed message to slack: %v", err)
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}
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}
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result.JiraIssueKey = &issue.Key
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logrus.Infof("Jira issue created: %s", result.JiraIssueKey)
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channelId, ts, err := t.Slack.PostMessage(
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t.Conf.Slack.Channels.RequestThreads,
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slack.MsgOptionDisableLinkUnfurl(),
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req.MainMessageBlocks(),
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)
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if err != nil {
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return result, fmt.Errorf("failed to post Slack message for request -- this means there is data that has been created that nobody knows about: %w", err)
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}
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result.SlackTimeStamp = ts
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result.SlackChannelId = channelId
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// fetch permalink to the posted message to update jira ticket with
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url, err := t.Slack.GetPermalink(&slack.PermalinkParameters{
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Channel: channelId,
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Ts: ts,
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})
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if err != nil {
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// TODO: retry?
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logrus.Errorf("Failed to retrieve permalink for Slack message for request -- this means we could not link the jira ticket to the slack thread: %s", err)
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}
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req.SlackThreadURL = url
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if issue != nil {
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rl := jira.RemoteLink{
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Object: &jira.RemoteLinkObject{
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URL: url,
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Title: "Slack Thread",
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},
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}
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_, res, err := t.Jira.AddIssueRemoteLink(issue.ID, &rl)
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defer res.Body.Close()
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if err != nil {
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// TODO: retry?
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logrus.Errorf("Failed to add remote link to Slack message thread (ts: '%s', link: '%s') for jira issue (key: '%s'): %s", ts, url, issue.Key, err)
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}
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}
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logrus.Infof("Request data: %+v", req)
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logrus.Tracef("request's db data json: %+v", req.DataJSON)
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logrus.Tracef("request's db data: %+v", req.Data)
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dbResult := t.DB.Create(req)
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logrus.Tracef("request db create result: %+v", dbResult)
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// it's not the end of the world if we cannot update the main message, so we try it, log it, and keep going
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blocks, err = req.MainMessageBlocks()
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if err != nil {
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logrus.Errorf("Failed to build slack blocks for original message update: %v", err)
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}
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_, _, _, err = t.Slack.UpdateMessage(
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t.Conf.Slack.Channels.RequestThreads,
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req.SlackTimeStamp,
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blocks,
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)
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if err != nil {
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logrus.Errorf("Failed to update original message: %v", err)
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}
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_, _, err = t.Slack.PostMessage(
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channelId,
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slack.MsgOptionTS(ts),
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slack.MsgOptionBlocks(req.FirstReplyMessageBlocks()...),
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)
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if err != nil {
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logrus.Errorf("failed to post follow-up message in thread: %s", err)
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}
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if req.Data.NeedsApproval() {
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req, err = t.ApprovalSetup(req)
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if err != nil {
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return result, fmt.Errorf("failed to setup approval: %w", err)
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}
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}
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return
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}
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```
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Here's how it looks in my Rust dream rewrite (thanks `color_eyre::Result`):
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```rust
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// fetch permalink to the posted message to update jira ticket with
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url, err := t.Slack.GetPermalink(&slack.PermalinkParameters{
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Channel: channelId,
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Ts: ts,
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})
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if err != nil {
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// TODO: retry?
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logrus.Errorf("Failed to retrieve permalink for Slack message for request -- this means we could not link the jira ticket to the slack thread: %s", err)
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}
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req.SlackThreadURL = url
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if issue != nil {
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rl := jira.RemoteLink{
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Object: &jira.RemoteLinkObject{
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URL: url,
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Title: "Slack Thread",
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},
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}
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_, res, err := t.Jira.AddIssueRemoteLink(issue.ID, &rl)
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defer res.Body.Close()
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if err != nil {
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// TODO: retry?
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logrus.Errorf("Failed to add remote link to Slack message thread (ts: '%s', link: '%s') for jira issue (key: '%s'): %s", ts, url, issue.Key, err)
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}
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}
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logrus.Infof("Request data: %+v", req)
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logrus.Tracef("request's db data json: %+v", req.DataJSON)
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logrus.Tracef("request's db data: %+v", req.Data)
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dbResult := t.DB.Create(req)
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logrus.Tracef("request db create result: %+v", dbResult)
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// it's not the end of the world if we cannot update the main message, so we try it, log it, and keep going
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blocks, err = req.MainMessageBlocks()
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if err != nil {
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logrus.Errorf("Failed to build slack blocks for original message update: %v", err)
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}
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_, _, _, err = t.Slack.UpdateMessage(
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t.Conf.Slack.Channels.RequestThreads,
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req.SlackTimeStamp,
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blocks,
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)
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if err != nil {
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logrus.Errorf("Failed to update original message: %v", err)
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}
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_, _, err = t.Slack.PostMessage(
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channelId,
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slack.MsgOptionTS(ts),
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slack.MsgOptionBlocks(req.FirstReplyMessageBlocks()...),
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)
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if err != nil {
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logrus.Errorf("failed to post follow-up message in thread: %s", err)
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}
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if req.Data.NeedsApproval() {
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req, err = t.ApprovalSetup(req)
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if err != nil {
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return result, fmt.Errorf("failed to setup approval: %w", err)
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}
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}
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return
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}
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```
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# Why Not Rust
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While I've made it clear that I prefer Rust, I also recognize that there are
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things that I consider Go to handle better.
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## Standard libraries
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Go has a big standard library and just includes a ton of stuff. I wish Rust had
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something similar for "blessed" "core" crates. I understand the standard library
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for a systems-level language must be small, but that's how I feel.
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## Go is Simple
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It's easy to get caught up trying to do things in Rust the "right" way and work
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with the borrow checker and think about the optimal solution -- to revel in the
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computer science puzzle that the compiler presents to you.
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In Go, that is simply less true. You will do the obvious thing at perhaps some
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slight performance cost and get back to implementing your feature and shipping
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code.
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## Go Compilation Speed
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The Go compiler is wonderfully quick. In my experience, though, there are
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usually codegen tools you end up adopting that offset this speed and slow things
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down again that require extra vigilance and tending to keep things fast.
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With Rust, you have one compiler speed: not so fast. It's still sufficiently
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quick for me, especially on a Ryzen 9 5950X or an Apple M1 Max. For most
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projects, it does a good job being incremental, too.
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But you will build Rust
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## Build Tinkering
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With Go, you're just gonna build the binary and run it.
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With Rust, you _do_ have to think about `--release` performance -- such as when
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writing Leetcode solutions against your friends.
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I'm getting nitpicky here, but... it's my article.
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