[PATCH 2/2] travis-ci: record and skip successfully built trees
- From
SZEDER Gábor <szeder.dev@gmail.com>
- Date
- Dec 27, 2017, 16:49 UTC
- Message-ID
- <20171227164905.13872-3-szeder.dev@gmail.com>
- In-Reply-To
- <20171227164905.13872-1-szeder.dev@gmail.com>
Travis CI dutifully builds and tests each new branch tip, even if its tree has previously been successfully built and tested. This happens often enough in contributors' workflows, when a work-in-progress branch is rebased changing e.g. only commit messages or the order or number of commits while leaving the resulting code intact, and is then pushed to a Travis CI-enabled GitHub fork.
This is wasting Travis CI's resources and is sometimes scary-annoying when the new tip commit with a tree identical to the previous, successfully tested one is suddenly reported in red, because one of the OSX build jobs happened to exceed the time limit yet again.
So extend our Travis CI build scripts to skip building commits whose trees have previously been successfully built and tested. Use the Travis CI cache feature to keep a record of the object names of trees that tested successfully, in a plain and simple flat text file, one line per tree object name. Append the current tree's object name at the end of every successful build job to this file, along with a bit of additional info about the build job (commit object name, Travis CI job number and id). Check, using a simple grep invocation, in each build job whether the current commit's tree is already in there, and skip the build if it is. Include a message in the skipped build job's trace log, containing the URL to the build job successfully testing that tree for the first time and instructions on how to force a re-build. Catch the case when a build job, which successfully built and tested a particular tree for the first time, is restarted and omit the URL of the previous build job's trace log, as in this case it's the same build job and the trace log has just been overwritten.
Using an ever-growing flat text file might seem like asking for trouble on the long run, but it's perfectly adequate for this purpose. Contributors' topic branches are short-lived in general, so this file won't grow large enough to cause any issues. Grepping through several tens of thousands such lines is sufficiently fast, so not even git/git's forever living integration branches will cause scalability issues with the current rate of ~1 push/day for a couple of decades. And even if we reach the point that this file grows too big, the caches can be deleted on Travis CI's web interface.
Note: this won't kick in if two identical trees are on two different branches, because Travis CI caches are not shared between build jobs of different branches.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> --- ci/lib-travisci.sh | 43 +++++++++++++++++++++++++++++++++++++++++++ ci/run-linux32-docker.sh | 2 ++ ci/run-static-analysis.sh | 2 ++ ci/run-tests.sh | 2 ++ ci/run-windows-build.sh | 2 ++ ci/test-documentation.sh | 2 ++ 6 files changed, 53 insertions(+)
diff --git a/ci/lib-travisci.sh b/ci/lib-travisci.sh index 348fe3c3c..05e73123f 100755 --- a/ci/lib-travisci.sh +++ b/ci/lib-travisci.sh @@ -21,6 +21,48 @@ skip_branch_tip_with_tag () { fi } +good_trees_file="$HOME/travis-cache/good-trees" + +# Save some info about the current commit's tree, so we can skip the build +# job if we encounter the same tree again and can provide a useful info +# message. +save_good_tree () { + echo "$(git rev-parse $TRAVIS_COMMIT^{tree}) $TRAVIS_COMMIT $TRAVIS_JOB_NUMBER $TRAVIS_JOB_ID" >>"$good_trees_file" +} + +# Skip the build job if the same tree has already been built and tested +# successfully before (e.g. because the branch got rebased, changing only +# the commit messages). +skip_good_tree () { + if ! good_tree_info="$(grep "^$(git rev-parse $TRAVIS_COMMIT^{tree}) " "$good_trees_file")" + then + # haven't seen this tree yet; continue the build job + return + fi + + echo "$good_tree_info" | { + read tree prev_good_commit prev_good_job_number prev_good_job_id + + if test "$TRAVIS_JOB_ID" = "$prev_good_job_id" + then + cat <<-EOF + Skipping build job for commit $TRAVIS_COMMIT. + This commit has already been built and tested successfully by this build job. + To force a re-build delete the branch's cache and then hit 'Restart job'. + EOF + else + cat <<-EOF + Skipping build job for commit $TRAVIS_COMMIT. + This commit's tree has already been built and tested successfully in build job $prev_good_job_number for commit $prev_good_commit. + The log of that build job is available at https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$prev_good_job_id + To force a re-build delete the branch's cache and then hit 'Restart job'. + EOF + fi + } + + exit 0 +} + # Set 'exit on error' for all CI scripts to let the caller know that # something went wrong. # Set tracing executed commands, primarily setting environment variables @@ -28,6 +70,7 @@ skip_branch_tip_with_tag () { set -ex skip_branch_tip_with_tag +skip_good_tree if test -z "$jobname" then diff --git a/ci/run-linux32-docker.sh b/ci/run-linux32-docker.sh index 3a8b2ba42..870a41246 100755 --- a/ci/run-linux32-docker.sh +++ b/ci/run-linux32-docker.sh @@ -22,3 +22,5 @@ docker run \ --volume "${HOME}/travis-cache:/tmp/travis-cache" \ daald/ubuntu32:xenial \ /usr/src/git/ci/run-linux32-build.sh $(id -u $USER) + +save_good_tree diff --git a/ci/run-static-analysis.sh b/ci/run-static-analysis.sh index 68dd0f080..fe4ee4e06 100755 --- a/ci/run-static-analysis.sh +++ b/ci/run-static-analysis.sh @@ -6,3 +6,5 @@ . ${0%/*}/lib-travisci.sh make coccicheck + +save_good_tree diff --git a/ci/run-tests.sh b/ci/run-tests.sh index ccdfc2b9d..eb5ba4058 100755 --- a/ci/run-tests.sh +++ b/ci/run-tests.sh @@ -7,3 +7,5 @@ ln -s $HOME/travis-cache/.prove t/.prove make --quiet test + +save_good_tree diff --git a/ci/run-windows-build.sh b/ci/run-windows-build.sh index 86999268a..d99a180e5 100755 --- a/ci/run-windows-build.sh +++ b/ci/run-windows-build.sh @@ -99,3 +99,5 @@ gfwci "action=log&buildId=$BUILD_ID" | cut -c 30- # Set exit code for TravisCI test "$RESULT" = "success" + +save_good_tree diff --git a/ci/test-documentation.sh b/ci/test-documentation.sh index 7a0a848e8..3d62e6c95 100755 --- a/ci/test-documentation.sh +++ b/ci/test-documentation.sh @@ -25,3 +25,5 @@ sed '/^GIT_VERSION = / d' stderr.log ! test -s stderr.log test -s Documentation/git.html grep '<meta name="generator" content="Asciidoctor ' Documentation/git.html + +save_good_tree
-- 2.15.1.500.g54ea76cc4