Dear all,
Here is a proposal to introduce directory-based configuration loading for
NaviServer using
nsd -t <directory>
Key properties:
* predictable lexicographic ordering
* improved maintainability for large configurations
* compatibility with both pure NaviServer and OpenACS deployments
* improved error localization
* alignment with established Unix configuration practices
The feature is simple to implement, non-intrusive, and immediate useful for
complex deployments.
Below are my design considerations. The goal would be to include this in the
NaviServer 5.1 release.
Comments of all kinds are always appreciated.
All the best
-g
---------------------------------------------------------------------------------------------------------------------------
## 1. Motivation
NaviServer currently requires the `-t` option to reference a single
Tcl configuration file. Large installations (both OpenACS-based and
pure NaviServer setups) increasingly require splitting configuration
into multiple smaller files for:
* improved readability and maintainability
* separation of defaults, parameters, modules, and per-server configuration
* easier isolation of syntax errors
* smaller diffs and clearer version control history
* provide a mechanism to include/remove sections without file editing
* reuse of configuration fragments across multiple server instances
At present, this requires explicit source logic inside a main
configuration file. This RFC proposes first-class support in
NaviServer for loading configuration from a directory, while
continuing support for single configuration files.
## 2. Proposed Feature
Extend NaviServer so that the `-t` option accepts either:
* a file (current behavior, unchanged), or
* a directory, interpreted as a configuration set.
Example:
nsd ... -t /usr/local/ns/conf/openacs-config.d
This proposal is strictly additive and does not modify existing
file-based behavior.
## 3. Directory interpretation
When the argument passed to -t is a directory, NaviServer shall:
1. Verify that the directory exists and is readable.
2. Enumerate all files in the directory matching *.tcl.
3. Sort these filenames lexicographically.
4. Evaluate each file in order using the same Tcl interpreter used
for a single configuration file.
Example directory contents:
00-bootstrap.tcl
10-parameters.tcl
20-network.tcl
30-runtime.tcl
40-db.tcl
50-modules-global.tcl
60-server-openacs.tcl
70-final.tcl
Load order:
00-bootstrap.tcl -> 10-parameters.tcl -> 20-network.tcl -> ... ->
70-final.tcl
Ordering is therefore explicit, predictable, and controlled solely by
filenames.
## 4. Variable scope and execution environment
All configuration fragments are executed in the same global Tcl
interpreter used today for monolithic configuration files.
As a result:
* Variables defined in earlier fragments are visible in later fragments.
* `ns_section` declarations behave exactly as in a single-file configuration.
* No special scoping rules or namespace changes are introduced.
This preserves full compatibility with existing configuration logic.
## 5. Behavior when `-t` is a file
When `-t` refers to a file, behavior remains unchanged:
nsd ... -t /usr/local/ns/conf/nsd-openacs.tcl
* Only that file is evaluated.
* No directory scanning or fragment loading occurs.
This ensures full backward compatibility and avoids unexpected behavior.
## 6. Error handling
If any configuration fragment loaded from a directory fails due to a
syntax error or runtime error:
* The error SHALL be reported with filename and line number.
* `nsd` SHALL terminate startup with a non-zero exit status.
This mirrors existing behavior for single-file configurations while
making error localization significantly easier.
## 7. Logging behavior
During startup, before sourcing each configuration fragment, `nsd`
SHOULD emit a log entry such as:
ns_log Notice "nsd: sourcing config fragment: <filename>"
This makes fragment ordering and loading behavior visible and debuggable.
## 8. Naming recommendations (non-normative)
While NaviServer does not enforce naming conventions, the following
scheme is strongly recommended:
NN-description.tcl
Where:
* 'NN' is a two-digit numeric prefix controlling load order
* 'description' is a short, human-readable identifier
Example:
00-bootstrap.tcl
10-parameters.tcl
20-network.tcl
30-runtime.tcl
40-db.tcl
50-modules-global.tcl
60-server-openacs.tcl
60-server-xotcl.tcl
60-server-cvs.tcl
70-final.tcl
This structure supports:
* multiple server configurations
* OpenACS and non-OpenACS servers
* consistent ordering across installations
## 9. Backward compatibility
This proposal is fully backward compatible:
* Existing configurations using `-t <file>` continue to work unchanged.
* Inline `source` commands remain supported.
* Directory-based configuration is opt-in and only activated when `-t`
references a directory.
No existing configuration files need to be modified.
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