e2c304d473
The main improvement is a double-fork to prevent zombie processes if the parent process exits after the (child) async process. This is a real possibility since the parent process sticks around to monitor the results of the async process. In the first fork, ignore SIGCHLD in the very unlikely case that the async process exits before the first fork. This is probably only possible if the async process exits immediately, perhaps due to a chdir() failure. Set SIGCHLD back to default in the async process so waitpid() will work as expected. Also update the comment on chdir() to more accurately reflect what is happening. Finally, add a test in certain debug builds to ensure the first fork exits very quickly. This only works when valgrind is not in use because valgrind makes forking so slow that it is hard to tell if the async process performed work or not (in the case that the second fork goes missing and the async process is a direct child).
pgBackRest
Building Documentation
General Builds
The pgBackRest documentation can output a variety of formats and target several platforms and PostgreSQL versions.
This will build all documentation with defaults:
./doc.pl
The user guide can be built for different platforms: centos6, centos7, and debian. This will build the HTML user guide for CentOS/RHEL 7:
./doc.pl --out=html --include=user-guide --var=os-type=centos7
Documentation generation will build a cache of all executed statements and use the cache to build the documentation quickly if no executed statements have changed. This makes proofing text-only edits very fast, but sometimes it is useful to do a full build without using the cache:
./doc.pl --out=html --include=user-guide --var=os-type=centos6 --no-cache
Each os-type has a default container image that will be used as a base for creating hosts. For centos6/centos7 these defaults are generally fine, but for debian it can be useful to change the image.
./doc.pl --out=html --include=user-guide --var=os-type=debian --var=os-image=debian:9
The following is a sample CentOS/RHEL 7 configuration that can be used for building the documentation.
# Install docker
sudo yum install -y yum-utils device-mapper-persistent-data lvm2
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install -y docker-ce
sudo systemctl start docker
# Install tools
sudo yum install -y git wget
# Install latex (for building PDF)
sudo yum install -y texlive texlive-titlesec texlive-sectsty texlive-framed texlive-epstopdf ghostscript
# Install Perl modules that do not have CentOS packages via CPAN
sudo yum install -y yum cpanminus
sudo yum groupinstall -y "Development Tools" "Development Libraries"
sudo cpanm install --force XML::Checker::Parser
# Add documentation test user
sudo groupadd test
sudo adduser -gtest -n testdoc
sudo usermod -aG docker testdoc
Building with Packages
A user-specified package can be used when building the documentation. Since the documentation exercises most pgBackRest functionality this is a great way to smoke-test packages.
The package must be located within the pgBackRest repo and the specified path should be relative to the repository base. test/package is a good default path to use.
Ubuntu 16.04:
./doc.pl --out=html --include=user-guide --no-cache --var=os-type=debian --var=os-image=ubuntu:16.04 --var=package=test/package/pgbackrest_2.08-0_amd64.deb
CentOS/RHEL 6:
./doc.pl --out=html --include=user-guide --no-cache --var=os-type=centos6 --var=package=test/package/pgbackrest-2.08-1.el6.x86_64.rpm
CentOS/RHEL 7:
./doc.pl --out=html --include=user-guide --no-cache --var=os-type=centos7 --var=package=test/package/pgbackrest-2.08-1.el7.x86_64.rpm
Packages can be built with test.pl using the following configuration on top of the configuration given for building the documentation.
# Install recent git
sudo yum remove -y git
sudo yum install -y https://centos7.iuscommunity.org/ius-release.rpm
sudo yum install -y git2u-all
# Install Perl modules
sudo yum install -y perl-ExtUtils-ParseXS perl-ExtUtils-Embed perl-ExtUtils-MakeMaker perl-YAML-LibYAML
# Install dev libraries
sudo yum install -y libxml2-devel openssl-devel
# Add test user with sudo privileges
sudo adduser -gtest -n test
sudo usermod -aG docker test
sudo chmod 750 /home/test
sudo echo 'test ALL=(ALL) NOPASSWD: ALL' > /etc/sudoers.d/pgbackrest
# Add pgbackrest user required by tests
sudo adduser -gtest -n pgbackrest