Software Configuration Management AE6382

Transcription

1 Software Configuration Management

2 Software Configuration Management What is it? Software Configuration Management is the process of tracking changes to software. Why use it? Maintain multiple branches and versions. Recover previous versions. Keep track of changes, ie, committed changes. When to use it? For text files: programs, data, and configuration files. Supports binary files: Word and Excel files, etc. In multi developer contexts: can assign blame for changes.

3 Software Configuration Management Used in both single user and multi user environments. There are two multi user paradigms Locked access A single developer checks-out a copy of a file before modifying it. The modified file is then checked-in. During check-out only a single developer has access to the file. Concurrent access Multiple developers work with their own copy of a file. Conflicts are resolved as the local copies are committed to the common repository.

4 Software Configuration Management There are many implementations of version control software. RCS (Revision Control System) is one of the earliest. It was developed along with Unix. It is implemented as check-in/check-out. CVS (Concurrent Versioning System) is built on top of RCS and implements a concurrent access scheme. Subversion is a newer and is designed as a replacement for CVS. It is more easily deployed as a server. It is rapidly displacing CVS as the version control system of choice. Visual Source Safe is part of Microsoft Visual Studio. It is a check-in/check-out system and only runs on Windows. There are other open source and commercial implementations available.

5 Runs on Linux, Unix, MacOS, and Windows. Files, properties, and versioning information is maintained in a repository. The developer works with a copy located in a local working directory. Subversion repositories are local or server-based. The URL of the repository describes the access method file://... a local file based repository svn:// - a repository using the built-in svnserver svn+ssh:// - an svnserver with ssh used to control access (not a tunnel) a web based repository, most common in multi user environments home page Subversion Book

6 URL Notes When using the file:// method, do not use it in multi user mode while the repository is located on a shared network disk. It is unreliable and will eventually corrupt your repository. When using the method, you can view the current head revision files using a normal browser.

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8 Plain SVN is a line mode system. ex, svn update There are several GUI clients TortoiseSVN is popular Windows client, explorer extension Download TortoiseSVN from

9 Installation of TortoiseSVN Download TortoiseSVN from Double click file TortoiseSVN win32-svn msi Installs as an explorer extension special file icons for affected files added right-click menu items Start Programs TortoiseSVN Includes a differences program After installation explorer or computer must be restarted.

10 Use Cases create a repository import initial files into new repository check out a repository into a working directory update a working directory change file svn properties add a new file to a repository commit changes to the repository checking status of files in working set listing files in repository show a files log entries revert to a previous version resolving conflicts

11 Create a Local Repository

12 Create a pair of directories/folders. work is the working directory. repos is the directory where repositories will reside.

13 Create the specific repository directory. Use the TortiseSVN Explorer extension, right click the mouse on the repos folder.

14 A dialog box will appear asking for the type of repository to create. The choice is either a Berkeley Database file or a file-based repository. In most cases the file-based repository is best. The line-mode equivalent is svnadmin create proj1 fs-type fsfs

15 Now the repos directory is filled with folders and files that are used by Subversion to manage the repository. The repository is still empty.

16 Import Project Files to Repository

17 The initial set of files that are to be placed under version control are created in the work directory. In this example a single file, matmult.c, is created. This is an optional step. It is used only if there is an existing project that is being added to a repository. See slides on Adding Files to repository.

18 The next slide shows the contents of matmult.c. In particular see line 5. The string $Id: $ identifies the revision number associated with the file. This string is updated to show the version id every time the working file is updated, if the appropriate property is set.

19 #include <stdio.h> #include <time.h> #define MAX 500 static char svnid[] = "$Id: $"; void printmat(double *a,int imax, int jmax) { } long int i,j; printf("enter printmat\n"); for (i=0;i<imax;i++) { for (j=0;j<jmax;j++) { printf("%5.2f ",*(a + (jmax * i) + j)); } printf("\n"); } int main(int argc, char **argv) { long int i,j, k; int iter; double a[max][max]; double b[max][max]; double c[max][max]; clock_t t1,t2; t1 = clock(); for(iter=0;iter<10;iter++) { for(i=0;i<max;i++) { for(j=0;j<max;j++) { c[i][j] = 0.0; for(k=0;k<max;k++) { c[i][j] = c[i][j] + a[i][k] * b[k][j]; } } } } t2 = clock(); printf("t1=%d, t2=%d\n",t1,t2); printf("cpu time=%8.3f\n",(float)(t2 - t1)/clocks_per_sec); /* printmat(c,max,max); */ } for(i=0;i<max;i++) { a[i][i] = 2.0; b[i][i] = 3.0; }

20 The next step is to import the initial set of files into the repository. Right-click the mouse on the work directory.

21 This dialog box requests the location of the repository. It is entered as a URL. In this case the repository is a local directory so use the file:// form. A web based URL might be

22 This is the result of the import operation. It shows that one file has been added to the repository. The current revision number is 1.

23 The contents of the work directory can now be discarded.

24 Check Out the Repository to a Working Directory

25 Create a subversion working directory under revision control. We will reuse the work directory. To do this delete the contents of the work directory. At least the files that were added to the repository. Now checkout the contents of the repository to the work directory.

26 This dialog box is used to control what is checked out and to where. The directory work will be created if it does not exist.

27 For a server based working directory, the file work usually has the same name as the repository.

28 This dialog box lists the files that were added to the working directory.

29 Opening the working directory. Subversion The TortoiseSVN extension results in changes to the file icons.

30 Additional information about revision controlled files can be displayed by using View/Details and then View/Choose Details

31 The dialog box that results from View/Choose Details The SVN parameters, if selected, will be displayed when View/Details is selected as the directory format.

32 The result of selecting SVN Revision and SVN Status.

33 Update a Working Directory

34 Right click on directory or file and select SVN Update. This will load the current version from the repository to the working directory. When using a multi user repository it is a good idea to execute an update before working on the file.

35 Set Subversion Properties

36 To set properties on svn controlled files

37 To set properties on svn controlled files.

38 To set properties on svn controlled files. The drop-down box shows the available properties.

39 svn:eol-style Subversion will set the end-of-line in a text file appropriate to the destination working directory. svn:keywords Informs Subversion to handle the keywords, eg, $Id: $, which will be updated when downloaded to the working directory. svn:executable Informs Subversion that the file is an executable file. It will set permissions on the working copy to allow execution.

40 For this file svn:keywords has been set to Id and svn:eol-style has been set to native.

41 Going back an looking at the work directory notice that the icon for the file matmult.c has changed. In this case it indicates that the svn properties for the file have changed.

42 Add a New File to a Working Directory

43 To add a new file, readme.txt, to the repository. Create the file in the working directory, then use svn add

44 The dialog box that lists the files to be added to the repository. And the result of the add operation.

45 The freshly added file has a + icon to indicate its status. Now set the properties of the file then commit it.

46 The status of the working directory after the commit operation. Note that readme.txt is level 3 and matmult.c is level 2.

47 Adding is the better way to put files into a repository. Create the file in the working directory. Add the file to the repository. Set the appropriate properties. Commit the file to the repository.

48 Commit Changes to Repository

49 Now commit the changed file to the repository.

50 The dialog that results from the commit operation allows you to enter a log message that describes the changes made.

51 The final dialog box verifying the update of the repository. The revision number is now 2. The icon for matmult.c reverts to the green check. Looking at the file matmult.c shows the following: static char svnid[] = "$Id: matmult.c :33:16Z latham $";

52 Listing the Contents of the Repository

53 The contents of the repository can be viewed by using the repository browser.

54 The list of files in the repository.

55 Show Log for File

56 To show a files log entries, right click the file and select TortoiseSVN Show Log. The window at the right shows every revision made that included a comment. Use TortoiseSVN Revision Graph for a complete list of all revisions.

57 Revert to a Previous Version

58 Right click on the file to revert, then select the revision number that you want.

59 Resolving Conflicts (todo)