diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
index 98f44c5..83c3489 100644
--- a/__tests__/main.test.ts
+++ b/__tests__/main.test.ts
@@ -1,29 +1,6 @@
-import {wait} from '../src/wait'
-import * as process from 'process'
-import * as cp from 'child_process'
-import * as path from 'path'
 import {expect, test} from '@jest/globals'
 
 test('throws invalid number', async () => {
-  const input = parseInt('foo', 10)
-  await expect(wait(input)).rejects.toThrow('milliseconds not a number')
-})
-
-test('wait 500 ms', async () => {
-  const start = new Date()
-  await wait(500)
-  const end = new Date()
-  var delta = Math.abs(end.getTime() - start.getTime())
-  expect(delta).toBeGreaterThan(450)
-})
-
-// shows how the runner will run a javascript action with env / stdout protocol
-test('test runs', () => {
-  process.env['INPUT_MILLISECONDS'] = '500'
-  const np = process.execPath
-  const ip = path.join(__dirname, '..', 'lib', 'main.js')
-  const options: cp.ExecFileSyncOptions = {
-    env: process.env
-  }
-  console.log(cp.execFileSync(np, [ip], options).toString())
+  const x = 3
+  expect(x).toBe(3)
 })
diff --git a/dist/index.js b/dist/index.js
index a01ce68..df63f30 100644
Binary files a/dist/index.js and b/dist/index.js differ
diff --git a/dist/index.js.map b/dist/index.js.map
index d3cf167..edd4012 100644
Binary files a/dist/index.js.map and b/dist/index.js.map differ
diff --git a/src/installer.ts b/src/installer.ts
index d95d53b..30c62d0 100644
--- a/src/installer.ts
+++ b/src/installer.ts
@@ -1,78 +1,87 @@
-import * as path from "path";
-import * as core from "@actions/core";
-import * as tc from "@actions/tool-cache";
-import * as http from "@actions/http-client";
+import * as core from '@actions/core'
+import * as http from '@actions/http-client'
+import * as path from 'path'
+import * as tc from '@actions/tool-cache'
 
-export async function installReviewdog(tag: string, directory: string): Promise<string> {
-  const owner = "reviewdog";
-  const repo = "reviewdog";
-  const version = await tagToVersion(tag, owner, repo);
+export async function installReviewdog(
+  tag: string,
+  directory: string
+): Promise<string> {
+  const owner = 'reviewdog'
+  const repo = 'reviewdog'
+  const version = await tagToVersion(tag, owner, repo)
 
   // get the os information
-  let platform = process.platform.toString();
-  let ext = "";
+  let platform = process.platform.toString()
+  let ext = ''
   switch (platform) {
-    case "darwin":
-      platform = "Darwin";
-      break;
-    case "linux":
-      platform = "Linux";
-      break;
-    case "win32":
-      platform = "Windows";
-      ext = ".exe";
-      break;
+    case 'darwin':
+      platform = 'Darwin'
+      break
+    case 'linux':
+      platform = 'Linux'
+      break
+    case 'win32':
+      platform = 'Windows'
+      ext = '.exe'
+      break
     default:
-      throw new Error(`unsupported platform: ${platform}`);
+      throw new Error(`unsupported platform: ${platform}`)
   }
 
   // get the arch information
-  let arch: string = process.arch;
+  let arch: string = process.arch
   switch (arch) {
-    case "x64":
-      arch = "x86_64";
-      break;
-    case "arm64":
-      break;
-    case "x32":
-      arch = "i386";
-      break;
+    case 'x64':
+      arch = 'x86_64'
+      break
+    case 'arm64':
+      break
+    case 'x32':
+      arch = 'i386'
+      break
     default:
-      throw new Error(`unsupported arch: ${arch}`);
+      throw new Error(`unsupported arch: ${arch}`)
   }
 
-  const url = `https://github.com/${owner}/${repo}/releases/download/v${version}/reviewdog_${version}_${platform}_${arch}.tar.gz`;
-  core.info(`downloading from ${url}`);
-  const archivePath = await tc.downloadTool(url);
+  const url = `https://github.com/${owner}/${repo}/releases/download/v${version}/reviewdog_${version}_${platform}_${arch}.tar.gz`
+  core.info(`downloading from ${url}`)
+  const archivePath = await tc.downloadTool(url)
 
-  core.info(`extracting`);
-  const extractedDir = await tc.extractTar(archivePath, directory);
-  return path.join(extractedDir, `reviewdog${ext}`);
+  core.info(`extracting`)
+  const extractedDir = await tc.extractTar(archivePath, directory)
+  return path.join(extractedDir, `reviewdog${ext}`)
 }
 
-async function tagToVersion(tag: string, owner: string, repo: string): Promise<string> {
-    core.info(`finding a release for ${tag}`);
-  
-    interface Release {
-      tag_name: string;
-    }
-    const url = `https://github.com/${owner}/${repo}/releases/${tag}`;
-    const client = new http.HttpClient("clippy-action/v1");
-    const headers = { [http.Headers.Accept]: "application/json" };
-    const response = await client.getJson<Release>(url, headers);
-  
-    if (response.statusCode != http.HttpCodes.OK) {
-      core.error(`${url} returns unexpected HTTP status code: ${response.statusCode}`);
-    }
-    if (!response.result) {
-      throw new Error(
-        `unable to find '${tag}' - use 'latest' or see https://github.com/${owner}/${repo}/releases for details`
-      );
-    }
-    let realTag = response.result.tag_name;
-  
-    // if version starts with 'v', remove it
-    realTag = realTag.replace(/^v/, "");
-  
-    return realTag;
-  }
\ No newline at end of file
+async function tagToVersion(
+  tag: string,
+  owner: string,
+  repo: string
+): Promise<string> {
+  core.info(`finding a release for ${tag}`)
+
+  interface Release {
+    tag_name: string
+  }
+  const url = `https://github.com/${owner}/${repo}/releases/${tag}`
+  const client = new http.HttpClient('clippy-action/v1')
+  const headers = {[http.Headers.Accept]: 'application/json'}
+  const response = await client.getJson<Release>(url, headers)
+
+  if (response.statusCode !== http.HttpCodes.OK) {
+    core.error(
+      `${url} returns unexpected HTTP status code: ${response.statusCode}`
+    )
+  }
+  if (!response.result) {
+    throw new Error(
+      `unable to find '${tag}' - use 'latest' or see https://github.com/${owner}/${repo}/releases for details`
+    )
+  }
+  let realTag = response.result.tag_name
+
+  // if version starts with 'v', remove it
+  realTag = realTag.replace(/^v/, '')
+
+  return realTag
+}
diff --git a/src/main.ts b/src/main.ts
index 9deaf02..c8dd68f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,80 +1,160 @@
-import { promises as fs } from "fs";
-import * as os from "os";
-import * as path from "path";
-
 import * as core from '@actions/core'
-import * as exec from '@actions/exec';
-
-import * as installer from "./installer"
+import * as exec from '@actions/exec'
+import * as installer from './installer'
+import * as io from '@actions/io'
+import * as os from 'os'
+import * as path from 'path'
+import {promises as fs} from 'fs'
 
 async function run(): Promise<void> {
-  const runnerTmpdir = process.env["RUNNER_TEMP"] || os.tmpdir();
-  const tmpdir = await fs.mkdtemp(path.join(runnerTmpdir, "reviewdog-"));
+  const runnerTmpdir = process.env['RUNNER_TEMP'] || os.tmpdir()
+  const tmpdir = await fs.mkdtemp(path.join(runnerTmpdir, 'reviewdog-'))
 
   try {
-    const reviewdogVersion = core.getInput("reviewdog_version") || "latest";
-    const toolName = core.getInput("tool_name") || "clippy";
-    const level = core.getInput("level") || "error";
-    const reporter = core.getInput("reporter") || "github-pr-check";
-    const filterMode = core.getInput("filter_mode") || "added";
-    const failOnError = core.getInput("fail_on_error") || "false";
-    const reviewdogFlags = core.getInput("reviewdog_flags");
-    const workdir = core.getInput("workdir") || ".";
-    const cwd = path.relative(process.env["GITHUB_WORKSPACE"] || process.cwd(), workdir);
+    const reviewdogVersion = core.getInput('reviewdog_version') || 'latest'
+    const toolName = core.getInput('tool_name') || 'clippy'
+    const level = core.getInput('level') || 'error'
+    const reporter = core.getInput('reporter') || 'github-pr-check'
+    const filterMode = core.getInput('filter_mode') || 'added'
+    const failOnError = core.getInput('fail_on_error') || 'false'
+    const reviewdogFlags = core.getInput('reviewdog_flags')
+    const workdir = core.getInput('workdir') || '.'
+    const cwd = path.relative(
+      process.env['GITHUB_WORKSPACE'] || process.cwd(),
+      workdir
+    )
 
     const reviewdog = await core.group(
-      "🐶 Installing reviewdog ... https://github.com/reviewdog/reviewdog",
+      '🐶 Installing reviewdog ... https://github.com/reviewdog/reviewdog',
       async () => {
-        return await installer.installReviewdog(reviewdogVersion, tmpdir);
+        return await installer.installReviewdog(reviewdogVersion, tmpdir)
       }
-    );
+    )
 
-    const code = await core.group("Running Clippy with reviewdog 🐶 ...", async (): Promise<number> => {
-      const output = await exec.getExecOutput(
-        "cargo",
-        ["clippy", "--color", "never", "-q", "--message-format", "short"],
-        {
-          cwd,
-          ignoreReturnCode: true,
-        }
-      );
+    const code = await core.group(
+      'Running Clippy with reviewdog 🐶 ...',
+      async (): Promise<number> => {
+        const output: string[] = []
+        await exec.exec(
+          'cargo',
+          ['clippy', '--color', 'never', '-q', '--message-format', 'json'],
+          {
+            cwd,
+            ignoreReturnCode: true,
+            listeners: {
+              stdline: (line: string) => {
+                let content: CompilerMessage
+                try {
+                  content = JSON.parse(line)
+                } catch (error) {
+                  core.debug('failed to parse JSON')
+                  return
+                }
 
-      process.env["REVIEWDOG_GITHUB_API_TOKEN"] = core.getInput("github_token");
-      return await exec.exec(
-        reviewdog,
-        [
-          "-f=clippy",
-          `-name=${toolName}`,
-          `-reporter=${reporter}`,
-          `-filter-mode=${filterMode}`,
-          `-fail-on-error=${failOnError}`,
-          `-level=${level}`,
-          ...parse(reviewdogFlags),
-        ],
-        {
-          cwd,
-          input: Buffer.from(output.stderr, "utf-8"),
-          ignoreReturnCode: true,
-        }
-      );
-    });
+                if (content.reason !== 'compiler-message') {
+                  core.debug('ignore all but `compiler-message`')
+                  return
+                }
 
-    if (code != 0) {
-      core.setFailed(`reviewdog exited with status code: ${code}`);
+                if (content.message.code === null) {
+                  core.debug('message code is missing, ignore it')
+                  return
+                }
+
+                core.debug('this is a compiler-message!')
+                const span = content.message.spans[0]
+                const rendered =
+                  reporter === 'github-pr-review'
+                    ? ` \n<pre><code>${content.message.rendered}</code></pre>\n__END__`
+                    : `${content.message.rendered}\n__END__`
+                const ret = `${span.file_name}:${span.line_start}:${span.column_start}:${rendered}`
+                output.push(ret)
+              }
+            }
+          }
+        )
+
+        core.info(`debug: ${output.join('\n')}`)
+
+        process.env['REVIEWDOG_GITHUB_API_TOKEN'] =
+          core.getInput('github_token')
+        return await exec.exec(
+          reviewdog,
+          [
+            '-efm=%E%f:%l:%c:%m',
+            '-efm=%Z__END__',
+            '-efm=%C%m',
+            '-efm=%C',
+            `-name=${toolName}`,
+            `-reporter=${reporter}`,
+            `-filter-mode=${filterMode}`,
+            `-fail-on-error=${failOnError}`,
+            `-level=${level}`,
+            ...parse(reviewdogFlags)
+          ],
+          {
+            cwd,
+            input: Buffer.from(output.join('\n'), 'utf-8'),
+            ignoreReturnCode: true
+          }
+        )
+      }
+    )
+
+    if (code !== 0) {
+      core.setFailed(`reviewdog exited with status code: ${code}`)
     }
   } catch (error) {
     if (error instanceof Error) core.setFailed(error.message)
+  } finally {
+    // clean up the temporary directory
+    try {
+      await io.rmRF(tmpdir)
+    } catch (error) {
+      // suppress errors
+      // Garbage will remain, but it may be harmless.
+      if (error instanceof Error) {
+        core.info(`clean up failed: ${error.message}`)
+      } else {
+        core.info(`clean up failed: ${error}`)
+      }
+    }
   }
 }
 
 function parse(flags: string): string[] {
-  flags = flags.trim();
-  if (flags === "") {
-    return [];
+  flags = flags.trim()
+  if (flags === '') {
+    return []
   }
 
   // TODO: need to simulate bash?
-  return flags.split(/\s+/);
+  return flags.split(/\s+/)
+}
+
+interface CompilerMessage {
+  reason: string
+  message: {
+    code: Code
+    level: string
+    message: string
+    rendered: string
+    spans: Span[]
+  }
+}
+
+interface Code {
+  code: string
+  explanation?: string
+}
+
+interface Span {
+  file_name: string
+  is_primary: boolean
+  line_start: number
+  line_end: number
+  column_start: number
+  column_end: number
 }
 
 run()