analyze-docker-build-errors

Docker Build Error Analysis

Analyze Dockerfile and build logs for PHP project build failures and provide targeted fixes.

Common Build Error Patterns

Error Category	Symptom	Root Cause
Extension compilation	configure: error: ...	Missing dev packages
Package not found	E: Unable to locate package	Wrong package name for base image
Permission denied	COPY failed: permission denied	File ownership or Docker socket
Memory exhausted	Allowed memory size exhausted	Composer or PHP memory limit
Context too large	sending build context... 2GB	Missing .dockerignore
Multi-stage failure	COPY --from=builder ... not found	Wrong stage name or path

Detection Patterns

1. Extension Compilation Failure

# ERROR: gd extension on Alpine
RUN docker-php-ext-install gd
# configure: error: png.h not found

# FIX (Alpine):
RUN apk add --no-cache libpng-dev libjpeg-turbo-dev freetype-dev \
    && docker-php-ext-configure gd --with-freetype --with-jpeg \
    && docker-php-ext-install -j$(nproc) gd

# FIX (Debian):
RUN apt-get update && apt-get install -y libpng-dev libjpeg62-turbo-dev libfreetype6-dev \
    && docker-php-ext-configure gd --with-freetype --with-jpeg \
    && docker-php-ext-install -j$(nproc) gd

2. Extension Dependencies by Base Image

Extension	Alpine Packages	Debian Packages
gd	libpng-dev libjpeg-turbo-dev freetype-dev	libpng-dev libjpeg62-turbo-dev libfreetype6-dev
intl	icu-dev	libicu-dev
zip	libzip-dev	libzip-dev
pdo_pgsql	postgresql-dev	libpq-dev
soap	libxml2-dev	libxml2-dev
xsl	libxslt-dev	libxslt1-dev
imagick	imagemagick-dev (PECL)	libmagickwand-dev (PECL)

3. Memory Exhausted During Build

# ERROR: Composer runs out of memory
RUN composer install
# PHP Fatal error: Allowed memory size of 134217728 bytes exhausted

# FIX: Increase memory limit for Composer
RUN php -d memory_limit=-1 /usr/bin/composer install --no-dev --optimize-autoloader

4. Context Too Large

# Required .dockerignore entries
.git
node_modules
vendor
var/cache
var/log
docker-compose*.yml
.env.local
tests
docs

5. Alpine Build Essentials

RUN apk add --no-cache --virtual .build-deps \
    $PHPIZE_DEPS build-base autoconf \
    && pecl install redis \
    && docker-php-ext-enable redis \
    && apk del .build-deps

Grep Patterns

# Find Dockerfiles with extension installs
Grep: "docker-php-ext-install" --glob "**/Dockerfile*"

# Find missing dev package installs before ext-install
Grep: "ext-install.*(gd|intl|zip|pdo_pgsql|imagick)" --glob "**/Dockerfile*"

# Find unrestricted memory Composer runs
Grep: "composer install|composer update" --glob "**/Dockerfile*"

# Find large base images
Grep: "FROM php:[0-9.]+-apache|FROM php:[0-9.]+-cli$" --glob "**/Dockerfile*"

# Check for .dockerignore existence
Glob: "**/.dockerignore"

Root Cause Analysis

Build Fails on CI but Works Locally

1. Different Docker version -- check docker version output
2. No BuildKit -- CI may not have DOCKER_BUILDKIT=1
3. Cache differences -- CI has cold cache, local has warm
4. Platform mismatch -- local ARM (M1/M2), CI AMD64

Extension Fails Only on Alpine

1. musl vs glibc -- some extensions require glibc patches
2. Package naming -- Alpine uses different package names
3. Missing build tools -- add build-base for compilation

Fix Templates

Alpine

RUN apk add --no-cache --virtual .build-deps $PHPIZE_DEPS <DEV_PACKAGES> \
    && docker-php-ext-configure <EXT> <OPTIONS> \
    && docker-php-ext-install -j$(nproc) <EXT> \
    && apk del .build-deps \
    && apk add --no-cache <RUNTIME_PACKAGES>

Debian

RUN apt-get update \
    && apt-get install -y --no-install-recommends <DEV_PACKAGES> \
    && docker-php-ext-configure <EXT> <OPTIONS> \
    && docker-php-ext-install -j$(nproc) <EXT> \
    && apt-get purge -y --auto-remove <DEV_ONLY_PACKAGES> \
    && rm -rf /var/lib/apt/lists/*

Severity Classification

Pattern	Severity	Impact
Extension compile failure	Critical	Build completely blocked
Memory exhausted	Critical	Build cannot complete
Package not found	Major	Build blocked, easy fix
Context too large	Major	Slow builds, wasted bandwidth
COPY path error	Minor	Build blocked, trivial fix

Output Format

### Build Error: [Category]

**Severity:** Critical/Major/Minor
**Stage:** `FROM ... AS <stage>`
**Line:** Dockerfile:line

**Error Message:**
<exact error from build log>

**Root Cause:**
[Explanation of why the build fails]

**Fix:**
```dockerfile
// Corrected Dockerfile instruction

Prevention: [How to avoid this error in future builds]