Command Execution in Containers

Some test scenarios require running commands within a container. In order to achieve this, the testcontainers library provides the ability to execute commands in 3 different ways:

• exec method of ContainerAsync (or Container)

Allows to run a command in an already running container.

• Image::exec_after_start

Only if you implement your own Image: Allows to define commands to be executed after the container is started and ready.

• Image::exec_before_ready

Only if you implement your own Image: Allows to define commands to be executed executed after the container has started, but before the Image::ready_conditions are awaited for.

Here we will focus on the first option, which is the most common one. The method expects an ExecCommand struct, and returns an ExecResult struct.

ExecCommand

The ExecCommand struct represents a command to be executed within a container. It includes the command itself and conditions to be checked on the command output and the container.

ExecCommand Usage

To create a new ExecCommand:

let command = ExecCommand::new(vec!["echo", "Hello, World!"])
    .with_container_ready_conditions(vec![/* conditions */])
    .with_cmd_ready_condition(CmdWaitFor::message_on_stdout("Hello, World!"));

CmdWaitFor

The CmdWaitFor enum defines conditions to be checked on the command's output.

ExecResult / SyncExecResult

For async version, the ExecResult struct represents the result of an executed command in a container. For non-async (blocking feature), the SyncExecResult struct is used instead.

The structs represents the result of an executed command in a container.

ExecResult Usage

To execute a command and handle the result:

let result = container.exec(command).await?;
let exit_code = result.exit_code().await?;
let stdout = result.stdout_to_vec().await?;
let stderr = result.stderr_to_vec().await?;