Implement auto deploy on pull requests

[imella]

Use 'auto_deploy_on: pr' configuration to enable automatic deployments
in a pull request.

[colinjfw]

🎉 Thanks @imella I'll take a look at this as soon as I can, I guess the tests don't run on forks so I'll have to figure that out first here.

[colinjfw]

I was reading through the GitHub events and I think there may be a simpler way to write this logic. There is a pull request "synchronized" event which I believe is fired when a PR is pushed:
https://developer.github.com/v3/activity/events/types/#pullrequestevent

We could add a new listener for this event and just trigger the automatic deployment logic on this event specifically. It would save an extra call to getAssociatedPullRequests as well.

[imella]

You're right! I'll check that "synchronized" event and make the necessary changes, thanks!

[colinjfw]

This looks great!

I like using the original PR code so if there are errors this will write comments into the pull request with the error messages.

Missed something

[colinjfw]

@imella tested this out, I realized this doesn't wait for the necessary checks before deploying like the code in the src/auto.ts. I think that we need to plug this into the code in there so that it will use the same logic across the board.

Thanks so much for your patience here :)

Going to play around with this for a bit...

[colinjfw]

Something like this will create a 'watch' on the new ref synchronized by the pull request. This will then wait for the necessary checks before continuing to deploy.

I think this is probably a better situation since most people may need to build containers or other artifacts before deploying in a PR.

$ git diff src/
diff --git a/src/auto.ts b/src/auto.ts
index 7e48a7e..7909807 100644
--- a/src/auto.ts
+++ b/src/auto.ts
@@ -31,6 +31,7 @@ export function auto(
    */
   async function addWatch(
     context: Context,
+    matchRef: string, // The ref to match for auto deployments.
     ref: string,
     sha: string,
     repository: PayloadRepository
@@ -40,7 +41,7 @@ export function auto(
       const conf = await config(context.github, context.repo());
       for (const target in conf) {
         const targetVal = conf[target]!;
-        if (!match(targetVal.auto_deploy_on, ref)) {
+        if (!match(targetVal.auto_deploy_on, matchRef)) {
           continue;
         }
         context.log.info(
@@ -283,8 +284,28 @@ export function auto(
     await addWatch(
       context,
       context.payload.ref,
+      context.payload.ref,
       context.payload.after,
       context.payload.repository
     );
   });
+
+  app.on("pull_request.synchronize", async context => {
+    await addWatch(
+      context,
+      "pr", // If auto_deploy_on matches "pr" then deploy.
+      context.payload.pull_request.head.ref,
+      context.payload.pull_request.head.sha,
+      context.payload.repository,
+    )
+  })
+  app.on("pull_request.opened", async context => {
+    await addWatch(
+      context,
+      "pr", // If auto_deploy_on matches "pr" then deploy.
+      context.payload.pull_request.head.ref,
+      context.payload.pull_request.head.sha,
+      context.payload.repository,
+    )
+  })
 }

[imella]

@imella tested this out, I realized this doesn't wait for the necessary checks before deploying like the code in the src/auto.ts. I think that we need to plug this into the code in there so that it will use the same logic across the board.

Thanks so much for your patience here :)

Going to play around with this for a bit...

Oh you're right, it doesn't wait for anything. So using 'watches' will only deploy if all checks passes, doesn't it?

I'll give it a go with those changes, thanks!

[jbergstroem]

Excited to see this in production :)

[colinjfw]

Thanks very much @imella!