diff --git a/action.yml b/action.yml
new file mode 100644
index 0000000..e853c32
--- /dev/null
+++ b/action.yml
@@ -0,0 +1,18 @@
+name: '"AWS CodeBuild run project" Action For GitHub Actions'
+description: 'Execute CodeBuild::startBuild for the current repo.'
+branding:
+  icon: 'cloud'
+  color: 'orange'
+inputs:
+  project-name:
+    description: 'AWS CodeBuild Project Name'
+    required: true
+  buildspec-override:
+    description: 'Buildspec Override'
+    required: false
+  env-passthrough:
+    description: 'Comma separated list of environment variables to send to CodeBuild'
+    required: false
+runs:
+  using: 'node12'
+  main: 'dist/index.js'
\ No newline at end of file
diff --git a/code-build.js b/code-build.js
new file mode 100644
index 0000000..6f474c0
--- /dev/null
+++ b/code-build.js
@@ -0,0 +1,139 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+const core = require("@actions/core");
+const github = require("@actions/github");
+const aws = require("aws-sdk");
+const assert = require("assert");
+
+module.exports = {
+  buildProject,
+  _buildProject,
+  waitForBuildEndTime,
+  inputs2Parameters,
+  buildSdk,
+  logName
+};
+
+function buildProject() {
+  // get a codeBuild instance from the SDK
+  const sdk = buildSdk();
+
+  // Get input options for startBuild
+  const params = inputs2Parameters();
+
+  return _buildProject(sdk, params);
+}
+
+async function _buildProject(sdk, params) {
+  // Start the build
+  const start = await sdk.codeBuild.startBuild(params).promise();
+
+  // Wait for the build to "complete"
+  const build = await waitForBuildEndTime(sdk, start.build);
+
+  // Signal the outcome
+  assert(
+    build.buildStatus === "SUCCEEDED",
+    `Build status: ${build.buildStatus}`
+  );
+}
+
+async function waitForBuildEndTime(sdk, { id, logs }, nextToken) {
+  const { codeBuild, cloudWatchLogs, wait = 1000 * 5 } = sdk;
+
+  // Get the CloudWatchLog info
+  const startFromHead = true;
+  const { cloudWatchLogsArn } = logs;
+  const { logGroupName, logStreamName } = logName(cloudWatchLogsArn);
+
+  // Check the state
+  const [batch, cloudWatch = {}] = await Promise.all([
+    codeBuild.batchGetBuilds({ ids: [id] }).promise(),
+    // The CloudWatchLog _may_ not be set up, only make the call if we have a logGroupName
+    logGroupName &&
+      cloudWatchLogs
+        .getLogEvents({ logGroupName, logStreamName, startFromHead, nextToken })
+        .promise()
+  ]);
+  // Pluck off the relevant state
+  const [current] = batch.builds;
+  const { nextForwardToken, events = [] } = cloudWatch;
+
+  // stdout the CloudWatchLog (everyone likes progress...)
+  events.forEach(({ message }) => console.log(message));
+
+  // We did it! We can stop looking!
+  if (current.endTime && !events.length) return current;
+
+  // More to do: Sleep for 5 seconds :)
+  await new Promise(resolve => setTimeout(resolve, wait));
+
+  // Try again
+  return waitForBuildEndTime(sdk, current, nextForwardToken);
+}
+
+function inputs2Parameters() {
+  const projectName = core.getInput("project-name", { required: true });
+
+  // The github.context.sha is evaluated on import.
+  // This makes it hard to test.
+  // So I use the raw ENV
+  const sourceVersion = process.env[`GITHUB_SHA`];
+  const sourceTypeOverride = "GITHUB";
+  const { owner, repo } = github.context.repo;
+  const sourceLocationOverride = `https://github.com/${owner}/${repo}.git`;
+
+  const buildspecOverride =
+    core.getInput("buildspec-override", { required: false }) || undefined;
+
+  const envVars = core
+    .getInput("env-passthrough", { required: false })
+    .split(",")
+
+    .map(i => i.trim());
+
+  const environmentVariablesOverride = Object.entries(process.env)
+    .filter(([key]) => key.startsWith("GITHUB_") || envVars.includes(key))
+    .map(([name, value]) => ({ name, value, type: "PLAINTEXT" }));
+
+  // The idempotencyToken is intentionally not set.
+  // This way the GitHub events can manage the builds.
+  return {
+    projectName,
+    sourceVersion,
+    sourceTypeOverride,
+    sourceLocationOverride,
+    buildspecOverride,
+    environmentVariablesOverride
+  };
+}
+
+function buildSdk() {
+  const codeBuild = new aws.CodeBuild({
+    customUserAgent: "aws-codbuild-run-project"
+  });
+
+  const cloudWatchLogs = new aws.CloudWatchLogs({
+    customUserAgent: "aws-codbuild-run-project"
+  });
+
+  assert(
+    codeBuild.config.credentials && cloudWatchLogs.config.credentials,
+    "No credentials. Try adding @aws-actions/configure-aws-credentials earlier in your job to set up AWS credentials."
+  );
+
+  return { codeBuild, cloudWatchLogs };
+}
+
+function logName(Arn) {
+  const [logGroupName, logStreamName] = Arn.split(":log-group:")
+    .pop()
+    .split(":log-stream:");
+  if (logGroupName === "null" || logStreamName === "null")
+    return {
+      logGroupName: undefined,
+      logStreamName: undefined
+    };
+  return { logGroupName, logStreamName };
+}
diff --git a/index.js b/index.js
new file mode 100644
index 0000000..9521c56
--- /dev/null
+++ b/index.js
@@ -0,0 +1,20 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+const core = require("@actions/core");
+const { buildProject } = require("./code-build");
+
+/* istanbul ignore next */
+if (require.main === module) {
+  run();
+}
+
+module.exports = run;
+
+async function run() {
+  try {
+    await buildProject();
+  } catch (error) {
+    core.setFailed(error.message);
+  }
+}
diff --git a/test/code-build-test.js b/test/code-build-test.js
new file mode 100644
index 0000000..d861edc
--- /dev/null
+++ b/test/code-build-test.js
@@ -0,0 +1,258 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+const {
+  logName,
+  inputs2Parameters,
+  waitForBuildEndTime
+} = require("../code-build");
+const { expect } = require("chai");
+
+describe("logName", () => {
+  it("return the logGroupName and logStreamName from an ARN", () => {
+    const arn =
+      "arn:aws:logs:us-west-2:111122223333:log-group:/aws/codebuild/CloudWatchLogGroup:log-stream:1234abcd-12ab-34cd-56ef-1234567890ab";
+    const test = logName(arn);
+    expect(test)
+      .to.haveOwnProperty("logGroupName")
+      .and.to.equal("/aws/codebuild/CloudWatchLogGroup");
+    expect(test)
+      .to.haveOwnProperty("logStreamName")
+      .and.to.equal("1234abcd-12ab-34cd-56ef-1234567890ab");
+  });
+
+  it("return undefined when the group and stream are null", () => {
+    const arn =
+      "arn:aws:logs:us-west-2:111122223333:log-group:null:log-stream:null";
+    const test = logName(arn);
+    expect(test)
+      .to.haveOwnProperty("logGroupName")
+      .and.to.equal(undefined);
+    expect(test)
+      .to.haveOwnProperty("logStreamName")
+      .and.to.equal(undefined);
+  });
+});
+
+describe("inputs2Parameters", () => {
+  const OLD_ENV = { ...process.env };
+  afterEach(() => {
+    process.env = { ...OLD_ENV };
+  });
+
+  const projectName = "project_name";
+  const repoInfo = "owner/repo";
+  const sha = "1234abcd-12ab-34cd-56ef-1234567890ab";
+
+  it("build basic parameters for codeBuild.startBuild", () => {
+    // This is how GITHUB injects its input values.
+    // It would be nice if there was an easy way to test this...
+    process.env[`INPUT_PROJECT-NAME`] = projectName;
+    process.env[`GITHUB_REPOSITORY`] = repoInfo;
+    process.env[`GITHUB_SHA`] = sha;
+    const test = inputs2Parameters();
+    expect(test)
+      .to.haveOwnProperty("projectName")
+      .and.to.equal(projectName);
+    expect(test)
+      .to.haveOwnProperty("sourceVersion")
+      .and.to.equal(sha);
+    expect(test)
+      .to.haveOwnProperty("sourceTypeOverride")
+      .and.to.equal("GITHUB");
+    expect(test)
+      .to.haveOwnProperty("sourceLocationOverride")
+      .and.to.equal(`https://github.com/owner/repo.git`);
+    expect(test)
+      .to.haveOwnProperty("buildspecOverride")
+      .and.to.equal(undefined);
+
+    // I send everything that starts 'GITHUB_'
+    expect(test)
+      .to.haveOwnProperty("environmentVariablesOverride")
+      .and.to.have.lengthOf(2);
+    expect(test.environmentVariablesOverride[0])
+      .to.haveOwnProperty("name")
+      .and.to.equal("GITHUB_REPOSITORY");
+    expect(test.environmentVariablesOverride[0])
+      .to.haveOwnProperty("value")
+      .and.to.equal(repoInfo);
+    expect(test.environmentVariablesOverride[0])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+
+    expect(test.environmentVariablesOverride[1])
+      .to.haveOwnProperty("name")
+      .and.to.equal("GITHUB_SHA");
+    expect(test.environmentVariablesOverride[1])
+      .to.haveOwnProperty("value")
+      .and.to.equal(sha);
+    expect(test.environmentVariablesOverride[1])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+  });
+
+  it("a project name is required.", () => {
+    expect(() => inputs2Parameters()).to.throw();
+  });
+
+  it("can send env-passthrough", () => {
+    // This is how GITHUB injects its input values.
+    // It would be nice if there was an easy way to test this...
+    process.env[`INPUT_PROJECT-NAME`] = projectName;
+    process.env[`GITHUB_REPOSITORY`] = repoInfo;
+    process.env[`GITHUB_SHA`] = sha;
+
+    process.env[`INPUT_ENV-PASSTHROUGH`] = `one, two 
+    , three,
+    four    `;
+
+    process.env.one = "_one_";
+    process.env.two = "_two_";
+    process.env.three = "_three_";
+    process.env.four = "_four_";
+
+    const test = inputs2Parameters();
+
+    expect(test)
+      .to.haveOwnProperty("environmentVariablesOverride")
+      .and.to.have.lengthOf(6);
+
+    expect(test.environmentVariablesOverride[2])
+      .to.haveOwnProperty("name")
+      .and.to.equal("one");
+    expect(test.environmentVariablesOverride[2])
+      .to.haveOwnProperty("value")
+      .and.to.equal("_one_");
+    expect(test.environmentVariablesOverride[2])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+
+    expect(test.environmentVariablesOverride[3])
+      .to.haveOwnProperty("name")
+      .and.to.equal("two");
+    expect(test.environmentVariablesOverride[3])
+      .to.haveOwnProperty("value")
+      .and.to.equal("_two_");
+    expect(test.environmentVariablesOverride[3])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+
+    expect(test.environmentVariablesOverride[4])
+      .to.haveOwnProperty("name")
+      .and.to.equal("three");
+    expect(test.environmentVariablesOverride[4])
+      .to.haveOwnProperty("value")
+      .and.to.equal("_three_");
+    expect(test.environmentVariablesOverride[4])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+
+    expect(test.environmentVariablesOverride[5])
+      .to.haveOwnProperty("name")
+      .and.to.equal("four");
+    expect(test.environmentVariablesOverride[5])
+      .to.haveOwnProperty("value")
+      .and.to.equal("_four_");
+    expect(test.environmentVariablesOverride[5])
+      .to.haveOwnProperty("type")
+      .and.to.equal("PLAINTEXT");
+  });
+});
+
+describe("waitForBuildEndTime", () => {
+  it("basic usages", async () => {
+    let count = 0;
+    const buildID = "buildID";
+    const cloudWatchLogsArn =
+      "arn:aws:logs:us-west-2:111122223333:log-group:/aws/codebuild/CloudWatchLogGroup:log-stream:1234abcd-12ab-34cd-56ef-1234567890ab";
+
+    const buildReplies = [
+      {
+        builds: [
+          { id: buildID, logs: { cloudWatchLogsArn }, endTime: "endTime" }
+        ]
+      }
+    ];
+    const logReplies = [{ events: [] }];
+    const sdk = help(
+      () => buildReplies[count++],
+      () => logReplies[count - 1]
+    );
+
+    const test = await waitForBuildEndTime(sdk, {
+      id: buildID,
+      logs: { cloudWatchLogsArn }
+    });
+
+    expect(test).to.equal(buildReplies.pop().builds[0]);
+  });
+
+  it("waits for a build endTime **and** no cloud watch log events", async function() {
+    this.timeout(25000);
+    let count = 0;
+    const buildID = "buildID";
+    const nullArn =
+      "arn:aws:logs:us-west-2:111122223333:log-group:null:log-stream:null";
+    const cloudWatchLogsArn =
+      "arn:aws:logs:us-west-2:111122223333:log-group:/aws/codebuild/CloudWatchLogGroup:log-stream:1234abcd-12ab-34cd-56ef-1234567890ab";
+
+    const buildReplies = [
+      { builds: [{ id: buildID, logs: { cloudWatchLogsArn } }] },
+      {
+        builds: [
+          { id: buildID, logs: { cloudWatchLogsArn }, endTime: "endTime" }
+        ]
+      },
+      {
+        builds: [
+          { id: buildID, logs: { cloudWatchLogsArn }, endTime: "endTime" }
+        ]
+      }
+    ];
+    const logReplies = [
+      undefined,
+      { events: [{ message: "got one" }] },
+      { events: [] }
+    ];
+    const sdk = help(
+      () => buildReplies[count++],
+      () => logReplies[count - 1]
+    );
+
+    const test = await waitForBuildEndTime(sdk, {
+      id: buildID,
+      logs: { cloudWatchLogsArn: nullArn }
+    });
+    expect(test).to.equal(buildReplies.pop().builds[0]);
+  });
+});
+
+function help(builds, logs) {
+  const codeBuild = {
+    batchGetBuilds() {
+      return {
+        async promise() {
+          return ret(builds);
+        }
+      };
+    }
+  };
+
+  const cloudWatchLogs = {
+    getLogEvents() {
+      return {
+        async promise() {
+          return ret(logs);
+        }
+      };
+    }
+  };
+
+  return { codeBuild, cloudWatchLogs, wait: 10 };
+
+  function ret(thing) {
+    if (typeof thing === "function") return thing();
+    return thing;
+  }
+}