[CC-1740] Add Elixir to SQLite #134
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- Created .formatter.exs for code formatting. - Added .gitattributes for text file handling. - Included .gitignore to exclude unnecessary files. - Set up codecrafters.yml for configuration. - Implemented download_sample_databases.sh to fetch sample databases. - Established mix.exs for project configuration. - Added README.md with instructions for the SQLite challenge. - Created your_program.sh for local execution. - Included compile.sh and run.sh for CodeCrafters integration. - Developed main.ex as the entry point for the SQLite implementation.
WalkthroughElixir support is added for the "Build Your Own SQLite" challenge, including starter templates, solution scaffolding, Docker build configuration, and course integration. The changes introduce scripts for compilation and execution, project configuration files, code formatting and ignore rules, documentation, and a basic Elixir CLI implementation to process SQLite database files. Changes
Sequence Diagram(s)sequenceDiagram
participant User
participant CLI (Elixir)
participant SQLite File
User->>CLI (Elixir): Run with [db_file, ".dbinfo"]
CLI (Elixir)->>SQLite File: Open db_file in binary mode
CLI (Elixir)->>SQLite File: Seek to byte 16, read 2 bytes
SQLite File-->>CLI (Elixir): Return page size bytes
CLI (Elixir)->>User: Output page size
Note over CLI (Elixir): If invalid args, print usage message
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Actionable comments posted: 1
🔭 Outside diff range comments (2)
solutions/elixir/01-dr6/code/download_sample_databases.sh (1)
3-10: 🛠️ Refactor suggestionAdd error handling to download script.
Withoutset -eorcurl -f, failed downloads won’t stop the script. It’s important to exit on any failure and detect HTTP errors.+# Exit on failure, undefined variables, and pipe errors +set -euo pipefail echo "Downloading superheroes.db: ~1MB (used in stage 7)" -curl -Lo superheroes.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/superheroes.db +curl -fLo superheroes.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/superheroes.db echo "Downloading companies.db: ~7MB (used in stage 8)" -curl -Lo companies.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/companies.db +curl -fLo companies.db https://raw.githubusercontent.com/codecrafters-io/sample-sqlite-databases/master/companies.db echo "Sample databases downloaded."compiled_starters/elixir/download_sample_databases.sh (1)
1-10: 🛠️ Refactor suggestionAdd fail-fast error handling to database downloads.
Currently the script lacks
set -eand flags to fail on HTTP errors, which could lead to partial or silent failures. To ensure robustness, prependset -eand usecurl -fLo:+#!/bin/sh +set -e echo "Downloading superheroes.db: ~1MB (used in stage 7)" - curl -Lo superheroes.db https://.../superheroes.db + curl -fLo superheroes.db https://.../superheroes.db echo "Downloading companies.db: ~7MB (used in stage 8)" - curl -Lo companies.db https://.../companies.db + curl -fLo companies.db https://.../companies.db echo "Sample databases downloaded."This change ensures any download error exits the script immediately.
🧹 Nitpick comments (17)
solutions/elixir/01-dr6/explanation.md (1)
14-18: Add language specifier to code fence.The fenced code block should specify a language for better syntax highlighting and adherence to markdown best practices.
-``` +```bash git add . git commit -m "pass 1st stage" # any msg git push origin master🧰 Tools
🪛 markdownlint-cli2 (0.17.2)
14-14: Fenced code blocks should have a language specified
null(MD040, fenced-code-language)
compiled_starters/elixir/lib/main.ex (2)
7-16: Consider adding file closing.The file is opened but never explicitly closed. While Elixir/Erlang will eventually clean up resources, it's a good practice to explicitly close files when done with them.
file = File.open!(database_file_path, [:read, :binary]) # You can use print statements as follows for debugging, they'll be visible when running tests. IO.puts(:stderr, "Logs from your program will appear here!") # Uncomment this to pass the first stage # :file.position(file, 16) # Skip the first 16 bytes of the header # <<page_size::16>> = IO.binread(file, 2) # IO.puts("database page size: #{page_size}") +# File.close(file)
5-16: Consider handling other commands gracefully.The code only handles the ".dbinfo" command but doesn't provide feedback for other commands. Consider adding an "else" clause to handle unrecognized commands with a helpful error message.
case command do ".dbinfo" -> file = File.open!(database_file_path, [:read, :binary]) # You can use print statements as follows for debugging, they'll be visible when running tests. IO.puts(:stderr, "Logs from your program will appear here!") # Uncomment this to pass the first stage # :file.position(file, 16) # Skip the first 16 bytes of the header # <<page_size::16>> = IO.binread(file, 2) # IO.puts("database page size: #{page_size}") + _ -> + IO.puts("Error: unknown command '#{command}'") endcompiled_starters/elixir/.codecrafters/run.sh (1)
1-8: Use/usr/bin/envin shebang for portability.
Prefer invoking the shell viaenvto ensure compatibility across environments where/bin/shmight differ.-#!/bin/sh +#!/usr/bin/env shstarter_templates/elixir/code/.codecrafters/run.sh (1)
1-8: Use/usr/bin/envin shebang for portability.
Align with other scripts and avoid hardcoding/bin/sh.-#!/bin/sh +#!/usr/bin/env shstarter_templates/elixir/code/.codecrafters/compile.sh (1)
1-8: Use/usr/bin/envin shebang for consistency.
Switch to#!/usr/bin/env shto mirror other scripts and improve portability.-#!/bin/sh +#!/usr/bin/env shsolutions/elixir/01-dr6/code/download_sample_databases.sh (1)
1-2: Use/usr/bin/envin shebang for portability.
Consistent shebang usage across scripts will avoid path issues.-#!/bin/sh +#!/usr/bin/env shsolutions/elixir/01-dr6/code/lib/main.ex (2)
7-11: Consider closing the file after reading.While Elixir's garbage collection will eventually close the file, it's a good practice to explicitly close it after reading to release system resources promptly.
file = File.open!(database_file_path, [:read, :binary]) :file.position(file, 16) # Skip the first 16 bytes of the header <<page_size::16>> = IO.binread(file, 2) IO.puts("database page size: #{page_size}") +File.close(file)
4-12: Add error handling for file operations.The current implementation uses
File.open!which will raise an exception if the file doesn't exist or can't be opened. Consider adding error handling to provide a more user-friendly message.case args do [database_file_path, command] -> case command do ".dbinfo" -> - file = File.open!(database_file_path, [:read, :binary]) - - :file.position(file, 16) # Skip the first 16 bytes of the header - <<page_size::16>> = IO.binread(file, 2) - IO.puts("database page size: #{page_size}") + try do + file = File.open!(database_file_path, [:read, :binary]) + + :file.position(file, 16) # Skip the first 16 bytes of the header + <<page_size::16>> = IO.binread(file, 2) + IO.puts("database page size: #{page_size}") + File.close(file) + rescue + error in File.Error -> + IO.puts("Error: Could not open database file '#{database_file_path}': #{error.reason}") + System.halt(1) + endstarter_templates/elixir/code/lib/main.ex (1)
12-15: Consider adding more context about SQLite file format.For educational purposes, it might be helpful to add a brief comment explaining why we're skipping 16 bytes (it's the SQLite file header) and that the page size is stored as a 16-bit integer at that position according to the SQLite file format specification.
# Uncomment this to pass the first stage # :file.position(file, 16) # Skip the first 16 bytes of the header # <<page_size::16>> = IO.binread(file, 2) # IO.puts("database page size: #{page_size}") +# Note: The first 16 bytes of a SQLite file contain the header +# The page size is stored as a 2-byte integer at offset 16 +# See: https://www.sqlite.org/fileformat.htmldockerfiles/elixir-1.18.Dockerfile (1)
23-25: Consider multi-stage build for leaner images
Right now you’re moving build artifacts into/app-cached. As an alternative, use a multi-stage Docker build: one stage to compile and cache deps, another minimal stage copying only the escript output.# Builder stage FROM elixir:1.18.3-alpine AS builder WORKDIR /app COPY . . RUN mix local.hex --force && \ mix local.rebar --force && \ mix deps.get && \ mix deps.compile && \ .codecrafters/compile.sh # Final stage FROM alpine:latest WORKDIR /app COPY --from=builder /app/codecrafters_sqlite /usr/local/bin/ ENTRYPOINT ["codecrafters_sqlite"]solutions/elixir/01-dr6/code/README.md (3)
61-61: Use clearer approximation notation
Replace~1MBwith a more standard form (e.g., “≈1 MB” or “about 1 MB”) for readability.
65-65: Use clearer approximation notation
Replace~7MBwith “≈7 MB” or “about 7 MB” to avoid confusion with markdown syntax.
67-68: Make phrasing more concise
Change “These aren’t included in the repository because they’re large in size.” to “These aren’t included because they’re large.”🧰 Tools
🪛 LanguageTool
[style] ~67-~67: This wording could be more concise.
Context: ...luded in the repository because they're large in size. You can download them by running this ...(ADJECTIVE_IN_ATTRIBUTE)
compiled_starters/elixir/README.md (3)
61-61: Use clearer approximation notation
In the compiled starter README, change~1MBto “≈1 MB” or “about 1 MB” for consistency.
65-65: Use clearer approximation notation
Update~7MBto “≈7 MB” or “about 7 MB” to prevent markdown parsing issues.
67-68: Streamline wording
Revise “These aren’t included in the repository because they're large in size.” to “These aren’t included because they’re large.”🧰 Tools
🪛 LanguageTool
[style] ~67-~67: This wording could be more concise.
Context: ...luded in the repository because they're large in size. You can download them by running this ...(ADJECTIVE_IN_ATTRIBUTE)
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📒 Files selected for processing (33)
compiled_starters/elixir/.codecrafters/compile.sh(1 hunks)compiled_starters/elixir/.codecrafters/run.sh(1 hunks)compiled_starters/elixir/.formatter.exs(1 hunks)compiled_starters/elixir/.gitattributes(1 hunks)compiled_starters/elixir/.gitignore(1 hunks)compiled_starters/elixir/README.md(1 hunks)compiled_starters/elixir/codecrafters.yml(1 hunks)compiled_starters/elixir/download_sample_databases.sh(1 hunks)compiled_starters/elixir/lib/main.ex(1 hunks)compiled_starters/elixir/mix.exs(1 hunks)compiled_starters/elixir/your_program.sh(1 hunks)course-definition.yml(1 hunks)dockerfiles/elixir-1.18.Dockerfile(1 hunks)solutions/elixir/01-dr6/code/.codecrafters/compile.sh(1 hunks)solutions/elixir/01-dr6/code/.codecrafters/run.sh(1 hunks)solutions/elixir/01-dr6/code/.formatter.exs(1 hunks)solutions/elixir/01-dr6/code/.gitattributes(1 hunks)solutions/elixir/01-dr6/code/.gitignore(1 hunks)solutions/elixir/01-dr6/code/README.md(1 hunks)solutions/elixir/01-dr6/code/codecrafters.yml(1 hunks)solutions/elixir/01-dr6/code/download_sample_databases.sh(1 hunks)solutions/elixir/01-dr6/code/lib/main.ex(1 hunks)solutions/elixir/01-dr6/code/mix.exs(1 hunks)solutions/elixir/01-dr6/code/your_program.sh(1 hunks)solutions/elixir/01-dr6/diff/lib/main.ex.diff(1 hunks)solutions/elixir/01-dr6/explanation.md(1 hunks)starter_templates/elixir/code/.codecrafters/compile.sh(1 hunks)starter_templates/elixir/code/.codecrafters/run.sh(1 hunks)starter_templates/elixir/code/.formatter.exs(1 hunks)starter_templates/elixir/code/.gitignore(1 hunks)starter_templates/elixir/code/lib/main.ex(1 hunks)starter_templates/elixir/code/mix.exs(1 hunks)starter_templates/elixir/config.yml(1 hunks)
🧰 Additional context used
🧬 Code Graph Analysis (3)
starter_templates/elixir/code/lib/main.ex (2)
compiled_starters/elixir/lib/main.ex (1)
main(2-20)solutions/elixir/01-dr6/code/lib/main.ex (1)
main(2-16)
compiled_starters/elixir/lib/main.ex (2)
solutions/elixir/01-dr6/code/lib/main.ex (1)
main(2-16)starter_templates/elixir/code/lib/main.ex (1)
main(2-20)
solutions/elixir/01-dr6/code/lib/main.ex (2)
compiled_starters/elixir/lib/main.ex (1)
main(2-20)starter_templates/elixir/code/lib/main.ex (1)
main(2-20)
🪛 markdownlint-cli2 (0.17.2)
solutions/elixir/01-dr6/explanation.md
14-14: Fenced code blocks should have a language specified
null
(MD040, fenced-code-language)
🪛 LanguageTool
solutions/elixir/01-dr6/code/README.md
[uncategorized] ~58-~58: Loose punctuation mark.
Context: ...s that you can use: 1. superheroes.db: - This is a small version of the tes...
(UNLIKELY_OPENING_PUNCTUATION)
[uncategorized] ~62-~62: Loose punctuation mark.
Context: ... - It is ~1MB in size. 1. companies.db: - This is a small version of the tes...
(UNLIKELY_OPENING_PUNCTUATION)
[style] ~67-~67: This wording could be more concise.
Context: ...luded in the repository because they're large in size. You can download them by running this ...
(ADJECTIVE_IN_ATTRIBUTE)
compiled_starters/elixir/README.md
[uncategorized] ~58-~58: Loose punctuation mark.
Context: ...s that you can use: 1. superheroes.db: - This is a small version of the tes...
(UNLIKELY_OPENING_PUNCTUATION)
[uncategorized] ~62-~62: Loose punctuation mark.
Context: ... - It is ~1MB in size. 1. companies.db: - This is a small version of the tes...
(UNLIKELY_OPENING_PUNCTUATION)
[style] ~67-~67: This wording could be more concise.
Context: ...luded in the repository because they're large in size. You can download them by running this ...
(ADJECTIVE_IN_ATTRIBUTE)
🪛 Hadolint (2.12.0)
dockerfiles/elixir-1.18.Dockerfile
[error] 10-10: invalid flag: --exclude
(DL1000)
🔇 Additional comments (36)
compiled_starters/elixir/.gitattributes (1)
1-1: Approve: Normalize line endings for Elixir compiled starter
Adding* text=autoensures consistent line endings across platforms and aligns with other language templates.compiled_starters/elixir/mix.exs (4)
1-4: Approve: Mix project module declaration
TheApp.MixProjectmodule anduse Mix.Projectinvocation follow standard Mix conventions.
5-14: Approve: Project settings configuration
The project is correctly configured with:codecrafters_sqliteas the app, semantic versioning, Elixir requirement, production flag, and escript main module.
16-21: Approve: Application runtime configuration
Declaring:loggerinextra_applicationsis appropriate for CLI logging.
23-29: Approve: Dependency placeholder
No active dependencies are declared yet. The commented examples provide guidance on adding Hex or Git dependencies when needed.solutions/elixir/01-dr6/code/.gitattributes (1)
1-1: Approve: Normalize line endings for Elixir solution code
Setting* text=autoaligns solution files with the starter template and ensures consistent Git behavior.starter_templates/elixir/config.yml (1)
1-3: Approve: Starter template metadata configuration
Therequired_executableanduser_editable_filekeys correctly describe the tooling requirement and user entry point.compiled_starters/elixir/.formatter.exs (1)
1-4: Approve: Formatter configuration
Theinputslist correctly includesmix.exs,.formatter.exs, and all Elixir source files underconfig,lib, andtest.solutions/elixir/01-dr6/code/codecrafters.yml (2)
1-5: Configuration: debug flag
Thedebug: falsedefault is sensible to minimize verbose logs. Developers can enable it when troubleshooting.
7-11: Configuration: language pack
Pinning toelixir-1.18ensures consistency across CI and local environments. Looks correct.starter_templates/elixir/code/.gitignore (1)
1-27: Comprehensive .gitignore for Elixir starter template
All common build artifacts—compiled binaries,_build,deps,cover, docs, crash dumps, archives, etc.—are excluded. This will keep the starter repo clean.course-definition.yml (1)
32-37: Enable Elixir track in course definition
Adding- slug: "elixir"correctly exposes the new Elixir implementation alongside other languages.solutions/elixir/01-dr6/code/.formatter.exs (1)
1-4: Elixir formatter configuration
Theinputspatterns covermix.exs,.formatter.exs, and all.ex/.exsfiles underconfig,lib, andtest. This aligns with standard Mix formatting conventions.compiled_starters/elixir/codecrafters.yml (2)
1-5: Configuration: debug flag in compiled starter
The defaultdebug: falseis appropriate. Enable when you need detailed runtime logs.
7-11: Configuration: language pack for compiled starter
Specifyingelixir-1.18ensures the compiled starter uses the correct Elixir version.starter_templates/elixir/code/.formatter.exs (1)
1-4: Looks good - appropriate formatter configuration.This is a standard Elixir formatter configuration that properly specifies patterns for files to be formatted by the
mix formattool.solutions/elixir/01-dr6/code/.codecrafters/run.sh (1)
1-11: Execution script looks correct.The run script properly executes the compiled Elixir program at the expected location with appropriate error handling. The use of
execis a good practice to replace the shell process with the target process.solutions/elixir/01-dr6/code/.codecrafters/compile.sh (1)
1-12: Compilation script is correctly implemented.The compile script correctly builds the Elixir project as an escript and moves it to the expected location for execution. The error handling with
set -eensures compilation failures are properly reported.solutions/elixir/01-dr6/explanation.md (1)
1-18: Clear instructions for first stage implementation.The explanation provides clear guidance on how to implement the first stage by directing the user to the relevant code file and showing the specific code to uncomment.
🧰 Tools
🪛 markdownlint-cli2 (0.17.2)
14-14: Fenced code blocks should have a language specified
null(MD040, fenced-code-language)
compiled_starters/elixir/lib/main.ex (1)
1-21: Main module implementation looks good.The CLI module correctly implements the entry point for the SQLite challenge with appropriate command handling. The commented code provides a good scaffold for users to implement the first stage.
compiled_starters/elixir/.codecrafters/run.sh (1)
9-12: Run script logic is correct.
Theset -eensures the script fails fast on any error, andexec ... "$@"properly forwards all arguments to the escript.starter_templates/elixir/code/.codecrafters/run.sh (1)
9-12: Starter template run script is solid.
set -eandexec /tmp/codecrafters-build-sqlite-elixir "$@"correctly handle errors and argument passing.solutions/elixir/01-dr6/code/.gitignore (1)
1-31: .gitignore rules are comprehensive for Elixir artifacts
The patterns cover database files, build outputs, coverage reports, dependencies, docs, crash dumps, and package artifacts. This aligns well with Elixir project conventions.starter_templates/elixir/code/.codecrafters/compile.sh (1)
9-13: Compile script follows best practices.
mix escript.buildand moving the executable into/tmpwithset -eis exactly what's needed for the CodeCrafters workflow.solutions/elixir/01-dr6/code/lib/main.ex (1)
1-17: Well-structured CLI module for SQLite database inspection.The implementation correctly opens the database file in binary mode, skips the 16-byte SQLite header, reads the 2-byte page size value, and outputs it in the expected format. The command-line argument handling is also properly implemented.
solutions/elixir/01-dr6/diff/lib/main.ex.diff (1)
10-19: Clean transformation from template to implementation.The diff correctly removes the debug statements and comments, and implements the necessary code to read and display the database page size. This transformation is exactly what we'd expect when moving from a template to a working solution.
compiled_starters/elixir/.codecrafters/compile.sh (1)
1-12: Well-structured compile script for the CodeCrafters environment.The script correctly builds the Elixir escript and moves it to the expected location for the CodeCrafters platform. The use of
set -eensures the script will exit immediately if any command fails, which is good practice.starter_templates/elixir/code/lib/main.ex (1)
1-21: Clear and helpful starter template for Elixir SQLite implementation.The template provides a good starting point with clear comments and instructions on what to uncomment to complete the first stage. The debug print statement helps users understand how to output debug information during testing.
compiled_starters/elixir/.gitignore (1)
1-30: Ignore patterns cover relevant build artifacts and temporary files.All key Elixir/Mix artifacts (
/_build/,/deps/,/cover/,/doc/), compiled escript binaries,.dbfiles, VM dumps, and other transient files are excluded. This will keep the repository clean and focused on source files.compiled_starters/elixir/your_program.sh (1)
1-25: Local run script correctly compiles and executes the Elixir escript.The shebang and
set -edirective ensure immediate exit on failure, and thecdinto the script directory guarantees the correct working context. Themix escript.buildandmvcommands mirror the remote compile script, andexecproperly launches the escript with passed arguments. Ensure the file has executable permissions (chmod +x) when committing.solutions/elixir/01-dr6/code/your_program.sh (1)
1-26: Solution run script follows the same compile-and-exec pattern.This script mirrors the starter version for local execution within the solution directory. It uses
set -e, compiles viamix escript.build, moves the binary, and execs it. Confirm executable permissions are set, and consider consolidating shared logic if maintenance overhead grows.starter_templates/elixir/code/mix.exs (1)
1-31: Mix project configuration is properly defined.The
project/0,application/0, anddeps/0definitions correctly set up:codecrafters_sqlitewith the appropriate version, Elixir requirement, and escript entry point. The empty deps list is suitable for a starter template, and the file aligns with standard Mix conventions.solutions/elixir/01-dr6/code/mix.exs (4)
1-4: Project module declaration is solid
TheApp.MixProjectmodule correctly usesMix.Projectand sets up the application scaffold.
5-14: Mix project configuration looks correct
Theproject/0function properly declares the app name, version, Elixir requirement, escript main module, and deps invocation.
17-21: OTP application settings are appropriate
Declaring only:loggerinextra_applicationsis sufficient for this CLI-focused project.
24-29: Dependencies placeholder is ready for future additions
No active deps are needed yet; commented examples can guide adding Hex or Git dependencies.
| # .git & README.md are unique per-repository. We ignore them on first copy to prevent cache misses | ||
| COPY --exclude=.git --exclude=README.md . /app | ||
|
|
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Invalid COPY --exclude flags: switch to .dockerignore
--exclude isn’t supported by Docker’s COPY. Use a .dockerignore file to omit .git and README.md.
Apply this diff:
- COPY --exclude=.git --exclude=README.md . /app
+ COPY . /appAnd add a .dockerignore alongside your Dockerfile:
.git
README.md
🧰 Tools
🪛 Hadolint (2.12.0)
[error] 10-10: invalid flag: --exclude
(DL1000)
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