From 8652a7ddbea90b088e4564925162cc4c22d7dcbb Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Mon, 16 Sep 2019 09:14:42 -0400
Subject: [PATCH] update the comments to reflect the strategy
---
.circleci/config.yml | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/.circleci/config.yml b/.circleci/config.yml
index d4cc783..ae41e43 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -29,10 +29,6 @@ jobs:
# time of this comment. We can bump it to a newer version when that
# makes sense. Meanwhile, the platform won't shift around beneath us
# unexpectedly.
- #
- # Note CircleCI cannot interpolate environment variables set here into
- # cache keys. Therefore, this value is *duplicated* below. When
- # changing it, change the value below as well.
NIXPKGS_REV: "3c83ad6ac13b67101cc3e2e07781963a010c1624"
steps:
@@ -50,6 +46,15 @@ jobs:
- "checkout"
- "run":
+ # CircleCI won't let us interpolate NIXPKGS_REV into a cache key.
+ # Only CircleCI's own environment variables or variables set via the
+ # web interface in a "context" can be interpolated into cache keys.
+ # However, we can interpolate the checksum of a file... Since we
+ # don't care about the exact revision, we just care that a new
+ # revision gives us a new string, we can write the revision to a
+ # file and then put the checksum of that file into the cache key.
+ # This way, we don't have to maintain the nixpkgs revision in two
+ # places and risk having them desynchronize.
name: "Prepare For Cache Key"
command: |
echo "${NIXPKGS_REV}" > nixpkgs.rev
@@ -77,10 +82,6 @@ jobs:
# If nixpkgs changes then potentially a lot of cached packages for
# the base system will be invalidated so we may as well drop them
# and make a new cache with the new packages.
- #
- # Note: The literal hash here must match NIXPKGS_REV set above.
- # CircleCI doesn't let us interpolate that value so we *duplicate*
- # it instead.
- paymentserver-nix-store-v1-{{ checksum "nixpkgs.rev" }}-{{ checksum "ristretto.nix" }}
- paymentserver-nix-store-v1-{{ checksum "nixpkgs.rev" }}-
- paymentserver-nix-store-v1-
--
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