How to use the "cache" in gitlab? - gitlab

Question

I have created the following test pipeline in gitlab:
job1:
stage: stage1
rules:
- if: $RUN != "run2"
when: always
- when: never
script:
- echo "Job stage1 updating file dates.txt"
- date >> data/dates.txt
cache:
key: statusfiles
paths:
- data/dates.txt
job2:
stage: stage2
rules:
- if: $RUN == "run2"
when: always
script:
- echo "Running stage 2"
- cat data/dates.txt
cache:
key: statusfiles
paths:
- data/dates.txt
where I want to use the "cache" feature of gitlab.
Here I first run job1 which update the file date.txt and add an entry to this example files, so it contains two lines.
However, when I run a new pipeline with job2 alone, the files contain only ONE line. The files seem to be the original, unmodified files.
How can I "upload" or "save" the files into the cache in job1, so I can use the updated file in a later run of job2?

Answer 1

Test first if the section "Share caches between jobs in the same branch" is relevant.
To have jobs in each branch use the same cache, define a cache with the key: >
$CI_COMMIT_REF_SLUG:
cache:
key: $CI_COMMIT_REF_SLUG
This configuration prevents you from accidentally overwriting the cache.
In your case, from the discussion, and from "How archiving and extracting works":
stages:
- build
- test
before_script:
- echo "Hello"
job A:
stage: build
rules:
- if: $RUN != "run3"
when: always
- when: never
script:
- mkdir -p data/
- date > data/hello.txt
cache:
key: build-cache
paths:
- data/
after_script:
- echo "World"
job B:
stage: test
rules:
- if: $RUN == "run3"
script:
- cat data/hello.txt
cache:
key: build-cache
paths:
- data/
By using a single runner on a single machine, you don’t have the issue where job B might execute on a runner different from job A.
This setup guarantees the cache can be reused between stages.
It only works if the execution goes from the build stage to the test stage in the same runner/machine. Otherwise, the cache might not be available.