I'm getting the same output as @George Boot. My pipeline seems to have caches up to some arbitrary point in my first stage and then wont cache any more because it "already exists".

Attachment 2614718555-Capture.PNG has been added with description: Originally embedded in Bitbucket issue #14144 in site/master

Attachment 4059371088-Screen%20Shot%202019-06-09%20at%202.23.46%20am.png has been added with description: Originally embedded in Bitbucket issue #14144 in site/master

Hey 740a1f9b5dc2 ,

Your cached docker image is ‘702.2MiB over the 1GiB upload limit’.

In my case the build case is around 700m after compressed but it still reports over 1GB limit. Can someone elaborate?

We use multi-stage builds, and the built in cache only seems to cache the first target:

+ docker build --target app -t app .
Sending build context to Docker daemon    123MB
Step 1/17 : FROM php:7.0-fpm-alpine as base
7.0-fpm-alpine: Pulling from library/php
Digest: sha256:b8ddafa001be63c0665e7c8501bdade02f29e77ceff88c57d9f142692d6401bb
Status: Downloaded newer image for php:7.0-fpm-alpine
 ---> f8f280d888a9
Step 2/17 : RUN ...
 ---> Using cache
 ---> 4e2ab674f07d
Step 3/17 : ENV PATH="/app/vendor/bin:${PATH}"
 ---> Using cache
 ---> adcbff086e7c
... # When we do FROM again it will no longer use the cache
Step 7/17 : FROM base as composer
 ---> 15f8d021ac02
Step 8/17 : RUN mkdir /tmp/composer && chmod 777 /tmp/composer
 ---> Running in adbe2935d2f9
Removing intermediate container adbe2935d2f9
 ---> b1587dff3fd4
Step 9/17 : ENV COMPOSER_HOME=/tmp/composer
 ---> Running in 18b1b49e35a7
Removing intermediate container 18b1b49e35a7
 ---> 22eb7b4f847d
Step 10/17 : COPY --from=composer /usr/bin/composer /usr/bin/composer
...

Same here. On the first build, it will build a cache and output some more details on what layers are getting cached etc.
Then, on the next build, it will download the cache but still run the docker build from the first step onwards, without using cached layers.

Also, after a build, it will not update the cache:

Skipping assembly of docker cache as one is already present
Cache "docker": Skipping upload for existing cache

@kmacleod thanks, but still no reason of fail:

Docker images saved to cache
Cache "docker": Compressing
Cache "docker": Compressed in 21 seconds
Cache "docker": Uploading 381.5 MiB
Cache "docker": Upload failed

Folks,

As of today, Pipelines is logging a bit more information about the assembly of the Docker layer cache in the Teardown section of the build. It now displays the reasoning behind whether or not the cache will be built and uploaded, as well as which images will be used to build the cache.

Hopefully this will make this feature a little more transparent.