From 9f267aa60871075ddcb8d937e79ec4ee4f19bdd7 Mon Sep 17 00:00:00 2001
From: Oliver Gould <ver@buoyant.io>
Date: Fri, 17 Nov 2023 20:55:21 +0000
Subject: [PATCH 1/2] ci: Fetch tarpaulin binary instead of compiling

This should shave 2+ minutes off of coverage tests.
---
 .github/workflows/coverage.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index bfd0d82516..dced3f5aed 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -31,7 +31,7 @@ jobs:
     steps:
       # XXX(ver) Workaround for a linking problem in the binary we store in the
       # devcontainer.
-      - run: rm -f /usr/local/bin/cargo-tarpaulin && cargo install cargo-tarpaulin
+      - run: scurl https://github.com/xd009642/tarpaulin/releases/download/0.27.1/cargo-tarpaulin-x86_64-unknown-linux-musl.tar.gz | tar -C /usr/local/bin -zxvf -
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       # linkerd-transport-header and opencencus-proto tests only check codegen.
       - run: cargo tarpaulin --locked --workspace --exclude=linkerd2-proxy --exclude=linkerd-transport-header --exclude=opencensus-proto --no-run

From a45e99b7e871097cceaab06334a3e2bf282dd118 Mon Sep 17 00:00:00 2001
From: Oliver Gould <ver@buoyant.io>
Date: Fri, 17 Nov 2023 21:13:22 +0000
Subject: [PATCH 2/2] ci: Enable coverage on main and all PRs

In preparation for some larger changes to the proxy, this change enables
codecov on main and on PRs that change code. We need to run coverage on
main so that PRs have a meaningful comparison point.

We use the styfle/cancel-workflow-action to prevent multiple runs
from clogging up Actions Runners.

We can adapt this configuration if it's too annoying, but it seems low
risk to add for now.
---
 .codecov.yml                   | 34 ++++++++++++++++++++++++++++++----
 .github/workflows/coverage.yml | 23 ++++++++++++++++++++---
 2 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/.codecov.yml b/.codecov.yml
index 97697e132f..38facf2e17 100644
--- a/.codecov.yml
+++ b/.codecov.yml
@@ -1,8 +1,34 @@
+codecov:
+  ignore:
+    - "linkerd/app/integration/src/**"
+    - "**/src/gen/**"
+    - "tools/**"
+
 coverage:
-  # Disable statuses until we sort out coverage more broadly. This is noisy as
-  # it is.
+  precision: 2
+  round: down
+  range: "70...100"
+
   status:
     project:
-      default: false
+      default:
+        target: auto
+        threshold: 2%
+        if_not_found: success
+        if_ci_failed: error
+        paths:
+          - "!linkerd/app/integration/src/**"
+          - "!**/src/gen/**"
+          - "!tools/**"
+
     patch:
-      default: false
+      default:
+        target: auto
+        threshold: 1%
+        if_not_found: success
+        if_ci_failed: error
+
+comment:
+  layout: "header, diff, files, footer"
+  behavior: default
+  require_changes: false
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index dced3f5aed..197bd28aff 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -4,13 +4,18 @@ permissions:
   contents: read
 
 on:
+  # We run coverage on main so that PRs can have a meaninful comparison that
+  # doesn't lag a whole day.
+  push:
+    branches:
+      - main
+
+  # Coverage runs on all code changes (as well as changes to the workflow).
   pull_request:
     paths:
       - .codecov.yml
       - .github/workflows/coverage.yml
-  schedule:
-    # Run daily at 11AM UTC (3AM PST).
-    - cron: '0 11 * * *'
+      - '**/*.rs'
 
 env:
   CARGO_INCREMENTAL: 0
@@ -19,6 +24,18 @@ env:
   RUSTUP_MAX_RETRIES: 10
 
 jobs:
+  # Cancel any previous runs of this workflow so coverage runs don't back up,
+  # especially on main (i.e. after merging several PRs).
+  cleanup:
+    runs-on: ubuntu-latest
+    permissions:
+      actions: write
+    steps:
+      - uses: styfle/cancel-workflow-action@01ce38bf961b4e243a6342cbade0dbc8ba3f0432
+        with:
+          all_but_latest: true
+          access_token: ${{ github.token }}
+
   test:
     name: codecov
     runs-on: ubuntu-latest