Artifact Inspection

Just-in-time artifacts such as containers, directories and files are represented by core Dagger objects such as Container, Directory and File respectively. Each of these core objects defines various functions, which you can "chain" to inspect or interact with the resulting artifact.

For example, the Directory object exposes an Entries() function, which lists the contents of the directory. Here is an example of using it, by chaining an Entries() function call to the returned Directory object of a Go builder Dagger Function:

dagger -m github.com/kpenfound/dagger-modules/golang@v0.2.0 call build --source=https://github.com/dagger/dagger --args=./cmd/dagger entries

Similarly, the File object exposes a Contents() function, which prints the contents of the corresponding file. Here is an example of using it to print the JSON report of a ruff linter Dagger Function, by chaining a Contents() function call to the returned File object:

dagger call -m github.com/dagger/dagger/dev/ruff@a29dadbb5d9968784847a15fccc5629daf2985ae lint --source https://github.com/dagger/dagger report contents

Similar, the File object exposes a Size() function, which returns the size of the corresponding file. Here is an example of obtaining the size of the ZIP file returned by a file archiving Dagger Function, by chaining a Size() function call to the returned File object:

dagger -m github.com/sagikazarmark/daggerverse/arc@40057665476af62e617cc8def9ef5a87735264a9 call  archive-directory --name=dagger-cli '--directory=https://github.com/dagger/dagger#main:cmd/dagger'  create --format=zip size

Container objects expose a WithExec() function, which lets you execute a command in the corresponding container. Here is an example of chaining this function call to a container returned by a Wolfi container builder Dagger Function, to execute the cowsay command:

dagger -m github.com/shykes/daggerverse/wolfi@v0.1.4 call container --packages=cowsay with-exec --args=cowsay,dagger stdout