hapistrano
A deployment library for Haskell applications
https://github.com/stackbuilders/hapistrano
Version on this page: | 0.3.6.1 |
LTS Haskell 18.28: | 0.4.3.0 |
Stackage Nightly 2021-06-14: | 0.4.2.0 |
Latest on Hackage: | 0.4.8.0 |
hapistrano-0.3.6.1@sha256:d9bc921eb74c69141f9a04fc9f9bf518dab32e506614daaededb71dac48893fc,4637
Module documentation for 0.3.6.1
Hapistrano
Hapistrano is a deployment library for Haskell applications similar to Ruby’s Capistrano.
Purpose
We created Hapistrano because:
- Deploys should be simple, but as close to atomic as possible (eg, they shouldn’t require much application downtime).
- Rollback should be trivial to achieve to bring the application back to the last-deployed state.
- Deploys shouldn’t fail because of dependency problems.
How it Works
Hapistrano (like Capistrano for Ruby) deploys applications to a new directory marked with a timestamp on the remote host. It creates this new directory quickly by placing a git repository for caching purposes on the remote server.
When the build process completes, it switches a symlink to the current
release directory, and optionally restarts the web server.
By default, Hapistrano keeps the last five releases on the target host filesystem and deletes previous releases to avoid filling up the disk.
Usage
Hapistrano 0.3.0.0 looks for a configuration file called hap.yaml
that
typically looks like this:
deploy_path: '/var/projects/my-project'
host: myserver.com
port: 2222
repo: 'https://github.com/stackbuilders/hapistrano.git'
revision: origin/master
build_script:
- stack setup
- stack build
restart_command: systemd restart my-app-service
The following parameters are required:
deploy_path
— the root of the deploy target on the remote host.repo
— the origin repository.revision
— the SHA1 or branch to deploy. If a branch, you will need to specify it asorigin/branch_name
due to the way that the cache repo is configured.
The following parameters are optional:
host
— the target host, if missing,localhost
will be assumed (which is useful for testing and playing withhap
locally).port
— SSH port number to use. If missing, 22 will be used.build_script
— instructions how to build the application in the form of shell commands.restart_command
— if you need to restart a remote web server after a successful rollback, specify the command that you use in this variable. It will be run after both deploy and rollback.vc_action
- Controls if version control related activity should take place. It defaults to true. When you don’t want activity like cloning, fetching etc. to take place, set this tofalse
.linux
- Specify, whether or not, the target system where Hapistrano will deploy to is a GNU/Linux or other UNIX (g.e. BSD, Mac). This is set totrue
by default so unless the target system is not GNU/Linux, this should not be necessary. The platform where Hapistrano is running won’t affect the available options for commands (g.e. A Mac deploying to a Ubuntu machine, doesn’t need this flag)run_locally:
- Instructions to run locally on your machine in the form of shell commands. Example:
run_locally:
- pwd
- bash deploy.sh
Note how we are even able to execute a bash script named deploy.sh
above. Be sure to use set -e
in your bash script to avoid
headaches. Hapistrano will stop the execution on non zero exit
codes. Without the usage of set -e
, there is a possiblity that your
bash script may return a zero exit code even if your intermediate
command resulted in an error.
After creating a configuration file as above, deploying is as simple as:
$ hap deploy
Rollback is also trivial:
$ hap rollback # to rollback to previous successful deploy
$ hap rollback -n 2 # go two deploys back in time, etc.
Environment Variables
Configuration files are parsed using loadYamlSettings, therefore, variable substitution is supported. Considering the following configuration file:
revision: "_env:HAPISTRANO_REVISION:origin/master
...
The revision
value could be overwritten as follows:
HAPISTRANO_REVISION=origin/feature_branch hap deploy
What to do when compiling on server is not viable
Sometimes the target machine (server) is not capable of compiling your
application because e.g. it has not enough memory and GHC exhausts it all.
You can copy pre-compiled files from local machine or CI server using
copy_files
and copy_dirs
parameters:
copy_files:
- src: '/home/stackbuilders/my-file.txt'
dest: 'my-file.txt'
copy_dirs:
- src: .stack-work
dest: .stack-work
src
maybe absolute or relative, it’s path to file or directory on local
machine, dest
may only be relative (it’s expanded relatively to cloned
repo) and specifies where to put the files/directories on target machine.
Directories and files with clashing names will be overwritten. Directories
are copied recursively.
Deploying to multiple machines concurrently
Beginning with Hapistrano 0.3.1.0 it’s possible to deploy to several
machines concurrently. The only things you need to do is to adjust your
configuration file and use targets
parameter instead of host
and port
,
like this:
targets:
- host: myserver-a.com
port: 2222
- host: myserver-b.com
# the rest is the same…
A few things to note here:
-
host
item is required for every target, butport
may be omitted and then it defaults to22
. -
The deployment will run concurrently and finish when interactions with all targets have finished either successfully or not. If at least one interaction was unsuccessful, the
hap
tool will exit with non-zero exit code. -
The log is printed in such a way that messages from several machines get intermixed, but it’s guaranteed that they won’t overlap (printing itself is sequential) and the headers will tell you exactly which machine was executing which command.
If you don’t specify host
and targets
, hap
will assume localhost
as
usually, which is mainly useful for testing.
Docker
If you would like to use Docker, there is a lightweight image available on Docker Hub.
License
MIT, see the LICENSE file.
Contributing
Pull requests for modifications to this program are welcome. Fork and open a PR. Feel free to email me if you have questions about what may be accepted before working on a PR.
If you’re looking for a place to start, you may want to check the open issue.
Changes
0.3.6.1
- Loose upper bound for yaml 0.11
0.3.6.0
- Add support to interpolate ENV variables in a configuration file.
- Add support for GHC 8.6.1
- Loose constraint for stm-2.5.0.0
0.3.5.10
- Updated upper bound for yaml 0.10
0.3.5.9
- Loose upper bound for path-io 1.4
0.3.5.8
- Loose upper bound for yaml 0.9
0.3.5.7
- Loose upper bound for aeson 1.4
0.3.5.6
- Add Dockerfile
0.3.5.5
- Adding tested compatibility with GHC 8.4
0.3.5.4
- Support for temporary 1.3
0.3.5.3
- Support for aeson 1.3
0.3.5.2
- Loose uppers bounds for async
0.3.5.1
- Standarize style
- When showing version information also show git branch and commit
0.3.5.0
- Add support for deploying to other Unix systems, besides GNU/Linux which didn’t supported all the flags that Hapistrano was using. See issue #63
0.3.4.0
- Use
git checkout
instead ofgit reset
to set the release revision
0.3.3.0
- Correct bounds for base. GHC support for versions older than 7.10 was dropped on 0.3.0.0
- Add
run_locally
to run user defined commands locally before deployment. Thanks to Sibi (GitHub: psibi) for this contribution
0.3.2.4
- Allow time 1.8
- Allow process 1.6
0.3.2.3
- Allow path-io 1.3
0.3.2.2
- Allow optparse-applicative 0.14
0.3.2.1
- Add support for help in subcommands. Thanks to Vanessa McHale (GitHub: vmchale) for this contribution
0.3.2.0
- Fix
-v
switch for hap. Thanks to Sibi (GitHub: psibi) for this contribution - Add
vc_action
to control version control related tasks. Thanks to Sibi (GitHub: psibi) for this contribution
0.3.1.0
- Fixed a bug with repos not being fetched properly.
- Implemented concurrent deployment to multiple hosts.
- Now completion tokens are dropped automatically like old releases.
0.3.0.1
- Reduced verbosity of some commands to make reading logs easier.
- Restart command is now invoked after activation of new release (as it should).
- Fix a typo in flag that specifies SSH port for
scp
. - Ensure that containing directories for files and directories to copy
exist before invoking
scp
.
0.3.0.0
- Add proper set of dependency version constraints.
- Use
optparse-applicative
to parse arguments. - Allow to specify non-standard SSH port.
- Drop support for GHCs older than 7.10 (because Chris Done’s
path
does not compile with them, see: https://github.com/chrisdone/path/issues/46). - Now Hapistrano uses
hap.yaml
file for all its configuration. - Added the ability to copy arbitrary files and directories verbatim from local machine to target host.
0.2.1.2
- Add change log (#23).
- Add
README.md
to extra source files. - Handle missing environment variables more graciously.
- Allow GHC 8 and base 4.9.
0.2.1.1
- Fix tests (#31).
0.2.1
- Use Stack (#17).
- Clean up package (#20).
- Fix tests (#25).
0.2.0.2
- GHC 7.10 support.
0.2.0.1
- Refactoring and documentation improvements.
0.2.0.0
- Various refactoring and relaxed dependency constraints.
0.1.0.2
- Print error messages to
stderr
, return non-zero exit code on failure.
0.1.0.1
- Initial release.