Create and deploy simple openscad api

A minimal frontend integration has been added to as a POC

resolves #219 and #222

api/src/docker/openscad/runScad.js

@@ -0,0 +1,68 @@
+const { exec } = require('child_process')
+const { promises } = require('fs')
+const { writeFile } = promises
+const { nanoid } = require('nanoid')
+
+module.exports.runScad = async ({
+  file,
+  settings: { size: { x = 500, y = 500 } = {} } = {}, // TODO add view settings
+} = {}) => {
+  const tempFile = await makeFile(file)
+
+  try {
+    const result = await runCommand(
+      `xvfb-run --auto-servernum --server-args "-screen 0 1024x768x24" openscad -o /tmp/${tempFile}/output.png --imgsize=${x},${y} /tmp/${tempFile}/main.scad`,
+      10000
+    )
+    return { result, tempFile }
+  } catch (error) {
+    return { error, tempFile }
+  }
+}
+
+module.exports.stlExport = async ({ file } = {}) => {
+  const tempFile = await makeFile(file)
+
+  try {
+    const result = await runCommand(
+      `openscad -o /tmp/${tempFile}/output.stl /tmp/${tempFile}/main.scad`,
+      300000 // lambda will time out before this, we might need to look at background jobs if we do git integration stl generation
+    )
+    return { result, tempFile }
+  } catch (error) {
+    return { error, tempFile }
+  }
+}
+
+async function makeFile(file) {
+  const tempFile = 'a' + nanoid() // 'a' ensure nothing funny happens if it start with a bad character like "-", maybe I should pick a safer id generator :shrug:
+  console.log(`file to write: ${file}`)
+
+  await runCommand(`mkdir /tmp/${tempFile}`)
+  await writeFile(`/tmp/${tempFile}/main.scad`, file)
+  return tempFile
+}
+
+async function runCommand(command, timeout = 5000) {
+  return new Promise((resolve, reject) => {
+    exec(command, (error, stdout, stderr) => {
+      if (error) {
+        console.log(`error: ${error.message}`)
+        console.log(`stderr: ${stderr}`)
+        console.log(`stdout: ${stdout}`)
+        reject(stdout || stderr) // it seems random if the message is in stdout or stderr, but not normally both
+        return
+      }
+      if (stderr) {
+        console.log(`stderr: ${stderr}`)
+        resolve(`stderr: ${stderr}`)
+        return
+      }
+      console.log(`stdout: ${stdout}`)
+      resolve(`stdout: ${stdout}`)
+    })
+    setTimeout(() => {
+      reject('timeout')
+    }, timeout)
+  })
+}