Information Technology Reference
In-Depth Information
change has occurred. A scheduled activity may be appropriate
for an off-hour process, such as running a set of exhaustive secu-
rity or load tests on the software. You can use
cron
to schedule
tasks, but many of the CI servers support a scheduling capability
as well.
•
Poll for changes
—A process wakes up on a regular interval and
checks for changes to the version control repository. If changes
are detected, it runs the integration build. All CI servers support
some type of “poll for changes” mechanism.
•
Event-driven
—Event-driven is like polling for changes, but
instead of the CI tool, the version control repository triggers the
build, based on a predefined change event. If the version control
repository detects a change, it initiates the build script.
Triggering Builds
Table 4-1 links the build type with how the build might be triggered.
Triggering Builds Using Different Mechanisms
TABLE 4-1
Build Type
Build Mechanism
Private
On-demand
Integration
On-demand, poll for changes, scheduled, event-driven
Release
On-demand, scheduled
When you dedicate a machine to integration builds, you drastically
reduce assumptions about environment and configuration, and you
help prevent the “but it works on my machine” problem from occur-
ring too late in development. Any local workstation typically has
slightly different configurations and dependencies, often undetectable,
from the deployment environments. If a developer makes local
