Merge pull request #64 from roc-lang/init-api

Change platform API to include `init` and `respond`

Author: Anton-4

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ concurrency:
 
 jobs:
   build-and-test:
-    runs-on: [ubuntu-20.04]
+    runs-on: [ubuntu-22.04]
     steps:
       - uses: actions/checkout@v3
 

.gitignore

@@ -20,6 +20,7 @@ app
 .DS_Store
 *.a
 *.dylib
+*.ll
 
 # roc linking files
 dynhost

Cargo.lock

@@ -15,24 +15,32 @@ A webserver [platform](https://github.com/roc-lang/roc/wiki/Roc-concepts-explain
 Run this example server with `$ roc helloweb.roc` (on linux, add `--linker=legacy`) and go to `http://localhost:8000` in your browser. You can change the port (8000) and the host (localhost) by setting the environment variables ROC_BASIC_WEBSERVER_PORT and ROC_BASIC_WEBSERVER_HOST.
 
 ```roc
-app [main] {
-     pf: platform "https://github.com/roc-lang/basic-webserver/releases/download/0.6.0/LQS_Avcf8ogi1SqwmnytRD4SMYiZ4UcRCZwmAjj1RNY.tar.gz"
+app [Model, server] {
+     pf: platform "https://github.com/roc-lang/basic-webserver/releases/download/0.7.0/vUnq0H5KAITUGuzI3av6AHYLS8LnaYI6qzIMsTNHq3M.tar.br"
 }
 
 import pf.Stdout
 import pf.Task exposing [Task]
 import pf.Http exposing [Request, Response]
 import pf.Utc
 
-main : Request -> Task Response []
-main = \req ->
+# Model is produced by `init`.
+Model : {}
 
-    # Log request date, method and url
-    date = Utc.now! |> Utc.toIso8601Str
-    Stdout.line! "$(date) $(Http.methodToStr req.method) $(req.url)"
+# With `init` you can set up a database connection once at server startup,
+# generate css by running `tailwindcss`,...
+# In this case we don't have anything to initialize, so it is just `Task.ok {}`.
 
-    Task.ok { status: 200, headers: [], body: Str.toUtf8 "<b>Hello, world!</b>\n" }
+server = { init: Task.ok {}, respond }
 
+respond : Request, Model -> Task Response [ServerErr Str]_
+respond = \req, _ ->
+    # Log request datetime, method and url
+    datetime = Utc.now! |> Utc.toIso8601Str
+
+    Stdout.line! "$(datetime) $(Http.methodToStr req.method) $(req.url)"
+
+    Task.ok { status: 200, headers: [], body: Str.toUtf8 "<b>Hello, world!</b></br>" }
 ```
 
 
@@ -43,3 +51,25 @@ If you'd like to contribute, check out our [group chat](https://roc.zulipchat.co
 ## Developing / Building Locally
 
 If you have cloned this repository and want to run the examples without using a packaged release (...tar.br), you will need to build the platform first by running `roc build.roc`. Run examples with `roc examples/hello.roc` (on linux, add `--linker=legacy`).
+
+## Benchmarking
+
+Basic webserver should have decent performance due to being built on top of Rust's [hyper](https://hyper.rs).
+That said, it has a few known issues that hurt performance:
+1. We do [extra data copying on every request](https://github.com/roc-lang/basic-webserver/issues/23).
+2. Until roc has effect interpreters, basic-webserver can only do blocking io for effects. To work around this, every request is spawned in a blocking thread.
+3. Until [sqlite improvements](https://github.com/roc-lang/basic-webserver/pull/61) land, we never prepare queries.
+
+That said, running benchmarks and debugging performance is still a great idea. It can help improve both Roc and basic-webserver.
+
+Lots of load generators exist. Generally, it is advised to use one that avoids [coordinated omission](https://www.youtube.com/watch?v=lJ8ydIuPFeU).
+A trusted generator that fits this criteria is [wrk2](https://github.com/giltene/wrk2) (sadly doesn't work on Apple Silicon).
+
+If you are benchmarking on a single machine, you can use the `TOKIO_WORKER_THREADS` environment variable to limit parallelism of the webserver.
+
+> Note: When benchmarking, it is best to run the load generator and the webserver on different machines.
+
+When benchmarking on a single 8 core machine with `wrk2`, these commands could be used (simply tune connections `-c` and rate `-R`):
+1. Optimized Build: `roc build --optimize my-webserver.roc`
+2. Launch server with 4 cores: `TOKIO_WORKER_THREADS=4 ./my-webserver`
+3. Generate load with 4 cores: `wrk -t4 -c100 -d30s -R2000 http://127.0.0.1:8000`

README.md

@@ -55,16 +55,9 @@ find . -type d -name "roc_nightly" -prune -o -type f -name "*.roc" -print | whil
     fi
 done
 
-# TODO use loop instead
-expect ci/expect_scripts/command.exp
-expect ci/expect_scripts/dir.exp
-expect ci/expect_scripts/echo.exp
-expect ci/expect_scripts/env.exp
-expect ci/expect_scripts/error-handling.exp
-expect ci/expect_scripts/file.exp
-expect ci/expect_scripts/hello-web.exp
-expect ci/expect_scripts/sleep.exp
-expect ci/expect_scripts/result.exp
+for script in ci/expect_scripts/*.exp; do
+    expect "$script"
+done
 
 # test building website
 $ROC docs platform/main.roc

ci/all_tests.sh

@@ -10,7 +10,7 @@ spawn $env(EXAMPLES_DIR)command
 expect "Listening on <http://127.0.0.1:8000>\r\n" {
     set curlOutput [exec curl -sS localhost:8000]
 
-    if {$curlOutput eq "Command succeeded"} {
+    if {$curlOutput eq "Command succeeded."} {
         expect "Z Get /\r\n" {
             exit 0
         }

ci/expect_scripts/command.exp

@@ -10,7 +10,7 @@ spawn $env(EXAMPLES_DIR)hello-web
 expect "Listening on <http://127.0.0.1:8000>\r\n" {
     set curlOutput [exec curl -sS localhost:8000]
 
-    if {$curlOutput eq "<b>Hello, world!</b>"} {
+    if {$curlOutput eq "<b>Hello from server</b></br>"} {
         expect "Z Get /\r\n" {
             exit 0
         }

ci/expect_scripts/hello-web.exp

@@ -0,0 +1,24 @@
+#!/usr/bin/expect
+
+# uncomment line below for debugging
+# exp_internal 1
+
+set timeout 7
+
+spawn $env(EXAMPLES_DIR)init-basic
+
+expect "Listening on <http://127.0.0.1:8000>\r\n" {
+    set curlOutput [exec curl -sS localhost:8000]
+
+    if {$curlOutput eq "<b>init gave me 🎁</b>"} {
+        expect "Z Get /\r\n" {
+            exit 0
+        }
+    } else {
+        puts "Error: curl output was different than expected: $curlOutput"
+        exit 1
+    }
+}
+
+puts stderr "\nError: output was different than expected."
+exit 1