Sources/XCMetricsPlugins/GitPlugin.swift

// Copyright (c) 2021 Spotify AB.
//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

import Foundation
import XCMetricsClient
import XCMetricsUtils

public struct GitPlugin {
    
    public enum GitData {
        // The current branch name
        case branch
        // The status of the repo
        case isDirty
        // The most recent commit hash in short format (6)
        case latestSHA
        // The branch's creator's email, redacted if necessary
        case userEmail(redacted: Bool)
    }

    private let gitDirectoryPath: String
    private let gitData: [GitData]
    private let shell: ShellOutFunction

    /// Initializes a `GitPlugin` using a configurable location for the git directory
    /// as well as the git data to attach to the associated build metadata.
    /// - Parameter gitDirectoryPath: The location of the git directory to use - usually Xcode's `${SRCROOT}` environment variable can be used (this variable is not available in the default environment variables for XCMetrics, and would need to be passed in).
    /// - Parameter gitData: The data to be retrieved from git (eg: the build's current branch).  Available data points can be found and added to the `GitData` enumeration.
    /// - Parameter shell: Will default to `shellGetStdout`
    public init(gitDirectoryPath: String, gitData: [GitData] = [.branch, .latestSHA, .isDirty, .userEmail(redacted: true)], shell: @escaping ShellOutFunction = shellGetStdout) {
        self.gitDirectoryPath = gitDirectoryPath
        self.gitData = gitData
        self.shell = shell
    }

    public func create() -> XCMetricsPlugin {
        return XCMetricsPlugin(name: "Git", body: { _ -> [String : String] in
            guard !gitData.isEmpty else { return [:] }

            return gitData.reduce(into: [String: String]()) {
                dictionary, target  in
                switch target {
                case .branch:
                    if let branch = try? shell("git", ["-C", gitDirectoryPath, "rev-parse", "--abbrev-ref", "HEAD"], nil, nil) {
                        dictionary["git_branch"] = branch
                    }
                case .isDirty:
                    let hasChanges = try? shell("git", ["-C", gitDirectoryPath, "status", "--short"], nil, nil)
                    // account for nil and empty string output
                    dictionary["git_is_dirty"] = hasChanges.isNilOrEmpty ? "false" : "true"
                        
                case .latestSHA:
                    if let latestSHA = try? shell("git", ["-C", gitDirectoryPath, "rev-parse", "--short=6", "--verify", "HEAD"], nil, nil) {
                        dictionary["git_commit_sha"] = latestSHA
                    }
                case .userEmail(let redacted):
                    if let userEmail = try? shell("git", ["-C", gitDirectoryPath, "config", "--get", "user.email"], nil, nil) {
                        dictionary["git_user_email"] = redacted ? userEmail.md5() : userEmail
                    }
                }
            }
        })
    }
}

fileprivate extension Optional where Wrapped: Collection {
    var isNilOrEmpty: Bool {
        return self?.isEmpty ?? true
    }
}