The C-Project web application provides a method of returning the last N number of lines from a log file via a REST-like web interface.

git clone [email protected]:marklap/cproject.git
cd cproject

In the dist/ directory are pre-compiled executables. Choose the appropriate one for your operating system.

If you prefer to build the executable yourself, follow the Build the Application instructions.

By default the server will listen on all interfaces (0.0.0.0) on TCP port 8080 and will only respond to requests for log files in the /var/log directory.

To start the server using the defaults, execute the following command:

./bin/cproject

To start the server with a customized configuration, reference the Command Line Usage section or execute ./bin/project -h to see the help information.

NOTE: Ensure the server is started with a user account that has permissions to read the files that exist in the directories provided with the -prefixes argument when starting the server.

To tail a log file, make a POST http request with a JSON request body of the following structure.

Structure

{
	"path": "/var/log/zoo.log",
	"num_lines": 10,
	"match_substrings": ["monkey", "octopus"],
	"case_sensitive": true,
}

Where:

• path: (required; string) the full path to a log file to tail
• num_lines: (integer) the number of lines to read from the end of the log file
• match_substrings: (list[string]) lines will only be returned if they match one of these strings
• case_sensitive: (boolean) if match_substrings is provided, set this to true to match in a case-sensitive manner

Responses are streamed ("chunked") to the client as they are yielded from the file reader. As such, while the content type of the response is technically text (text/plain MIME type), each chunk can be read as an individual JSON object.

Structure

{"host": "web.server.zoo:8080", "line": "2024-02-20T07:10:42Z marklap fed the monkey 2 bananas"}
{"host": "web.server.zoo:8080", "line": "2024-02-20T07:10:42Z marklap fed the octopus 3 crabs"}

Where:

• host: (string) the host that responded with the line
• line: (string) a line from the log file

Using curl:

 $ curl -v localhost:8080/tail -d '{"num_lines":2,"path":"/var/log/zoo.log","match_substrings":["monkey","octopus"],"case_sensitive":true}'
*   Trying 127.0.0.1:8080...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /tail HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.68.0
> Accept: */*
> Content-Length: 102
> Content-Type: application/x-www-form-urlencoded
> 
* upload completely sent off: 102 out of 102 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Wed, 21 Feb 2024 15:13:40 GMT
< Content-Length: 1731
< Content-Type: text/plain; charset=utf-8
< 
{"host": "web.server.zoo:8080", "line": "2024-02-20T07:10:42Z marklap fed the monkey 2 bananas"}
{"host": "web.server.zoo:8080", "line": "2024-02-20T07:10:42Z marklap fed the octopus 3 crabs"}
* Connection #0 to host localhost left intact

./bin/cproject -h
Usage of ./bin/cproject:
  -ip string
    	IP address to listen on (default "0.0.0.0")
  -port int
    	port to listen on (default 8080)
  -prefixes string
    	path prefixes to use for path validation [':' deliminted] (default "/var/log")

Ensure you have go 1.20+ installed.

To build using Make:

make build

To build for *nix/Mac using the go build tool:

go build -o ./bin/cproject ./cmd/

To build for Windows using the go build tool:

go build -o ./bin/cproject.exe ./cmd/

Run tests using Make:

make test

Run tests using go test tool:

go test -v