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    b05a3e28cf24
    automation: perform tasks on remote machines · b05a3e28cf24
    Gregory Szorc authored
    Sometimes you don't have access to a machine in order to
    do something. For example, you may not have access to a Windows
    machine required to build Windows binaries or run tests on that
    platform.
    
    This commit introduces a pile of code intended to help
    "automate" common tasks, like building release artifacts.
    
    In its current form, the automation code provides functionality
    for performing tasks on Windows EC2 instances.
    
    The hgautomation.aws module provides functionality for integrating
    with AWS. It manages EC2 resources such as IAM roles, EC2
    security groups, AMIs, and instances.
    
    The hgautomation.windows module provides a higher-level
    interface for performing tasks on remote Windows machines.
    
    The hgautomation.cli module provides a command-line interface to
    these higher-level primitives.
    
    I attempted to structure Windows remote machine interaction
    around Windows Remoting / PowerShell. This is kinda/sorta like
    SSH + shell, but for Windows. In theory, most of the functionality
    is cloud provider agnostic, as we should be able to use any
    established WinRM connection to interact with a remote. In
    reality, we're tightly coupled to AWS at the moment because
    I didn't want to prematurely add abstractions for a 2nd cloud
    provider. (1 was hard enough to implement.)
    
    In the aws module is code for creating an image with a fully
    functional Mercurial development environment. It contains VC9,
    VC2017, msys, and other dependencies. The image is fully capable
    of building all the existing Mercurial release artifacts and
    running tests.
    
    There are a few things that don't work. For example, running
    Windows tests with Python 3. But building the Windows release
    artifacts does work. And that was an impetus for this work.
    (Although we don't yet support code signing.)
    
    Getting this functionality to work was extremely time consuming.
    It took hours debugging permissions failures and other wonky
    behavior due to PowerShell Remoting. (The permissions model for
    PowerShell is crazy and you brush up against all kinds of
    issues because of the user/privileges of the user running
    the PowerShell and the permissions of the PowerShell session
    itself.)
    
    The functionality around AWS resource management could use some
    improving. In theory we support shared tenancy via resource
    name prefixing. In reality, we don't offer a way to configure
    this.
    
    Speaking of AWS resource management, I thought about using a tool
    like Terraform to manage resources. But at our scale, writing a
    few dozen lines of code to manage resources seemed acceptable.
    Maybe we should reconsider this if things grow out of control.
    Time will tell.
    
    Currently, emphasis is placed on Windows. But I only started
    there because it was likely to be the most difficult to implement.
    It should be relatively trivial to automate tasks on remote Linux
    machines. In fact, I have a ~1 year old script to run tests on a
    remote EC2 instance. I will likely be porting that to this new
    "framework" in the near future.
    
    # no-check-commit because foo_bar functions
    
    Differential Revision: https://phab.mercurial-scm.org/D6142
    b05a3e28cf24
    History
    automation: perform tasks on remote machines
    Gregory Szorc authored
    Sometimes you don't have access to a machine in order to
    do something. For example, you may not have access to a Windows
    machine required to build Windows binaries or run tests on that
    platform.
    
    This commit introduces a pile of code intended to help
    "automate" common tasks, like building release artifacts.
    
    In its current form, the automation code provides functionality
    for performing tasks on Windows EC2 instances.
    
    The hgautomation.aws module provides functionality for integrating
    with AWS. It manages EC2 resources such as IAM roles, EC2
    security groups, AMIs, and instances.
    
    The hgautomation.windows module provides a higher-level
    interface for performing tasks on remote Windows machines.
    
    The hgautomation.cli module provides a command-line interface to
    these higher-level primitives.
    
    I attempted to structure Windows remote machine interaction
    around Windows Remoting / PowerShell. This is kinda/sorta like
    SSH + shell, but for Windows. In theory, most of the functionality
    is cloud provider agnostic, as we should be able to use any
    established WinRM connection to interact with a remote. In
    reality, we're tightly coupled to AWS at the moment because
    I didn't want to prematurely add abstractions for a 2nd cloud
    provider. (1 was hard enough to implement.)
    
    In the aws module is code for creating an image with a fully
    functional Mercurial development environment. It contains VC9,
    VC2017, msys, and other dependencies. The image is fully capable
    of building all the existing Mercurial release artifacts and
    running tests.
    
    There are a few things that don't work. For example, running
    Windows tests with Python 3. But building the Windows release
    artifacts does work. And that was an impetus for this work.
    (Although we don't yet support code signing.)
    
    Getting this functionality to work was extremely time consuming.
    It took hours debugging permissions failures and other wonky
    behavior due to PowerShell Remoting. (The permissions model for
    PowerShell is crazy and you brush up against all kinds of
    issues because of the user/privileges of the user running
    the PowerShell and the permissions of the PowerShell session
    itself.)
    
    The functionality around AWS resource management could use some
    improving. In theory we support shared tenancy via resource
    name prefixing. In reality, we don't offer a way to configure
    this.
    
    Speaking of AWS resource management, I thought about using a tool
    like Terraform to manage resources. But at our scale, writing a
    few dozen lines of code to manage resources seemed acceptable.
    Maybe we should reconsider this if things grow out of control.
    Time will tell.
    
    Currently, emphasis is placed on Windows. But I only started
    there because it was likely to be the most difficult to implement.
    It should be relatively trivial to automate tasks on remote Linux
    machines. In fact, I have a ~1 year old script to run tests on a
    remote EC2 instance. I will likely be porting that to this new
    "framework" in the near future.
    
    # no-check-commit because foo_bar functions
    
    Differential Revision: https://phab.mercurial-scm.org/D6142