Designing a Package

Many of the criteria for good package development described in this section require you to make trade-offs. Satisfying all requirements equally is often difficult. The following criteria are presented in order of importance. However, this sequence is meant to serve as a flexible guide depending on your circumstances. Although each of these criteria is important, it is up to you to optimize these requirements to produce a good set of packages.

Select a package name.

Oracle Solaris uses a hierarchical naming strategy for IPS packages. Wherever possible, design your package names to fit into the same scheme. Try to keep the last part of your package name unique so that users can specify a short package name to commands such as pkg install.

Optimize for client-server configurations.

Consider the various patterns of software use (client and server) when laying out packages. Good package design divides the affected files to optimize installation of each configuration type. For example, for a network protocol implementation, the package user should be able to install the client without necessarily installing the server. If client and server share implementation components, create a base package that contains the shared bits.

Package by functional boundaries.

Packages should be self-contained and distinctly identified with a set of functionality. For example, a package that contains ZFS should contain all ZFS utilities and be limited to only ZFS binaries.

Packages should be organized from a user's point of view into functional units.

Package along license or royalty boundaries.

Put code that requires royalty payments due to contractual agreements or that has distinct software license terms in a dedicated package or group of packages. Do not disperse the code into more packages than necessary.

Avoid or manage overlap between packages.

Packages that overlap cannot be installed at the same time. An example of packages that overlap are packages that deliver different content to the same file system location. Since this error might not be caught until the user attempts to install the package, overlapping packages can provide a poor user experience. The pkglint(1) tool can help to detect this error during the package authoring process.

If the package content must differ, declare an exclude dependency so that IPS does not allow these packages to be installed together.

Correctly size packages.

A package represents a single unit of software, and is either installed or not installed. (See the discussion of facets in Optional Software Components to understand how a package can deliver optional software components.) Packages that are always installed together should be combined. Since IPS downloads only changed files on update, even large packages update quickly if change is limited.