trac2gitea

trac2gitea is a command-line utility for migrating Trac projects to Gitea.

Scope

At present the following Trac data is converted:

• Trac users mapped onto Gitea usernames (can be customised by providing an explicit mapping)
• Trac components, priorities, resolutions, severities, types and versions to Gitea labels (can be customised by providing an explicit mapping)
• Trac milestones to Gitea milestones
• Trac tickets to Gitea issues
  • Trac ticket attachments to Gitea issue attachments
  • Trac ticket comments to Gitea issue comments with markdown text conversion
  • Trac ticket component, priority, resolution, severity, type and version changes to Gitea issue label changes
  • Trac ticket milestone changes to Gitea issue milestone changes
  • Trac ticket owner changes to Gitea issue assignee changes
  • Trac ticket "close" and "reopen" status changes to Gitea issue equivalents
  • Trac ticket summary changes to Gitea issue title changes
  • Trac ticket labels to Gitea issue labels
  • Trac ticket and comment owners to Gitea issue assignees
• Trac Wiki pages to files in the Gitea wiki repository
  • Markdown text conversion
  • Preservation of Trac wiki page history as separate wiki repository commits
• Trac to Gitea markdown conversions (copes with most cases but some Trac constructs may, possibly of necessity, not translate perfectly)
  • link anchors
  • block quotes
  • code blocks (single and multi-line)
  • definition lists
  • Trac bold, italic and underlines to markdown equivalents
  • headings
  • lists - bulletted, numbered, lettered and roman numbered
  • [br] paragraph breaks
  • tables (basic support)
  • Trac links:
  • images
  • [[url|text]] style
  • [url text] style
  • http://... and https://... links
  • htdocs:... (files are stored in a htdocs subdirectory of the Gitea wiki repository)
  • CamelCase inter-wiki links
  • wiki:... inter-wiki links
  • attachment:... current ticket or wiki page attachment references
  • attachment:...:ticket:... ticket attachment references
  • attachment:...:wiki:... wiki attachment references (files are stored in a attachments/<pageName> subdirectory of the Gitea wiki repository)
  • ticket:... ticket references
  • comment:... current ticket comment references
  • comment:...:ticket:... ticket comment references
  • milestone:... milestone references
  • changeset:... changeset references
  • source:... source file references

Requirements

The utility requires access to both the Trac and Gitea filestore. It retrieves data directly from the Trac database and writes into the Gitea database. Access to the Gitea project wiki is by checking out the wiki git repository.

The Gitea project must have been created prior to the migration as must the Gitea project wiki if a Trac wiki is to be converted (this can however just consist of an empty Home.md welcome page).

Usage

Usage: ./trac2gitea [options] <trac-root> <gitea-root> <gitea-org> <gitea-repo> [<user-map>] [<label-map>] [<revision-map>]
Options:
      --app-ini string            Path to Gitea configuration file (app.ini). If not set, fetch the configuration from the standard locations. Useful if Gitea is running in a Docker container and you need a separate configuration file to reference the data on the host volumes.
      --db-only                   convert database only
      --default-user string       Fallback Gitea user if a Trac user cannot be mapped to an existing Gitea user. Defaults to <gitea-org>
      --generate-maps             generate default user/label mappings into provided map files (note: no conversion will be performed in this case)
      --no-wiki-push              do not push wiki on completion
      --overwrite                 overwrite existing data (by default previously-imported issues, labels, wiki pages etc are skipped)
      --verbose                   verbose output
      --wiki-convert-predefined   convert Trac predefined wiki pages - by default we skip these
      --wiki-dir string           directory into which to checkout (clone) wiki repository - defaults to cwd
      --wiki-only                 convert wiki only
      --wiki-token string         password/token for accessing wiki repository (ignored if wiki-url provided)
      --wiki-url string           URL of wiki repository - defaults to <server-root-url>/<gitea-user>/<gitea-repo>.wiki.git

• <trac-root> is the root of the Trac project filestore containing the Trac config file in subdirectory conf/trac.ini
• <gitea-root> is the root of the Gitea installation
• <gitea-user> is the owner of the Gitea project being migrated to
• <gitea-repo> is the Gitea repository (project) name being migrated to
• <user-map> is a file containing mappings from Trac users to Gitea user names - see below
• <label-map> is a file containing mappings from Trac items to Gitea labels - see below
• <revision-map> is a file containing mappings from svn revisions to corresponding git commits - see below

User Mappings

A file mapping from Trac users onto Gitea usernames can be provided via the <user-map> parameter. This is a text file containing lines of the form: <trac-user> = <gitea-username>

A default version of the mapping file can be generated by providing the --generate-maps flag. This will write the default mapping into the user mapping file but not perform any actual data conversions. The file can then be reviewed and edited as appropriate and the actual conversion process run by removing the --generate-maps flag.

If the <user-map> parameter is omitted, the conversion will proceed using the default mapping.

The default mapping maps a Trac user onto a Gitea user where the Gitea user has any of the following:

• the same user name
• the same "full" name
• the same email address

Where no mapping exists for a Trac user (the user map contains a line <trac-user> =):

• the Gitea repository owner provided on the command line will be used as the author of any issues or comments
• any Trac tickets assigned to the user will be left unassigned in Gitea
• the Trac user will be recorded as the "original author" of any Gitea issues

Where a mapping exists for a Trac user, the mapped Gitea user will be used in all relevant issues, comments etc.

Label Mappings

A file mapping from Trac component, priority, resolution, severity, type and version names onto Gitea label names can be provided via the <label-map> parameter. This is a text file containing lines of the form: <label-type>:<trac-item-name> = <gitea-label-name> where <label-type> must be one of component, priority, resolution, severity, type and version.

As with user mappings, a default version of the mapping file can be generated by providing the --generate-maps flag. This will write the default mapping into the label mapping file but not perform any actual data conversions. Again, the file can then be reviewed and edited then actual conversion process run by removing the --generate-maps flag. The mapping file can be edited so that <gitea-label-name> is unset for any Trac item (e.g. resolution:fixed =), in which case no Gitea label will be created for the Trac item.

The default mapping maps a Trac item name onto a Gitea label of the same name whether or not the Gitea label already exists.

If the <label-map> parameter is omitted, the conversion will proceed using the default mapping.

Revision Mappings

When using Subgit to convert a subversion repository to git, git-notes are attached to each commit created from the svn changeset, e.g.

r4640 myapp/trunk

These can easily be extracted and used as a <revision-map> file:

git log --all --format="%H=%N" > revisions.txt

This produces a file that looks like this:

e06f33e922f84aca19701889724ef858d6aef9a8=r3992 myapp/trunk
c3f16196bdb1d25f8a8fa85bdad5a569cf481f2a=r3991 myapp/trunk
3c8f9ed45c943f3d4817d65600cd254d20337ab1=r3990 myapp/trunk
fca57ea123049cc56549c602e0daffc9c127fac6=r3987 myapp/trunk

Pass in this file as a <revision-map> and trac2gitea will re-write svn revision references in the ticket comments, e.g.:

• See r3992 becomes See e06f33e922f84aca19701889724ef858d6aef9a8
• Implemented in r3987-r3991 becomes Implemented in fca57ea123049cc56549c602e0daffc9c127fac6..c3f16196bdb1d25f8a8fa85bdad5a569cf481f2a

if the <revision-map> parameter is omitted, the conversion will proceed without trying to map svn revisions to git commits.

Limitations

The current trac access code is written for sqlite only.

Most of the SQL used by the converter is fairly generic so porting to a different database type should hopefully not be particularly difficult.

Ideally, adapting the trac code to use GORM (like the gitea code) to support multiple database types should be straight forward.

For anyone using a different trac database, the database connection is created in:

• Trac: accessor/trac/defaultAccessor.go, func CreateDefaultAccessor

All trac database accesses are in package accessor.trac.

Building

From the root of the source tree run:

make

This will build the application as an executable trac2gitea (in the source tree root directory) and run the tests.

To build the application itself without running the tests, use:

make build

Missing dependencies can be fetched using:

make deps

Docker

In order to improve the reproducibility, one can leverage Docker:

docker compose build
docker compose run --rm go-shell
go version
...
make mockdeps && make
...