chore: minor refactor of the prometheus module

go.mod

@@ -5,16 +5,16 @@ go 1.21
 require (
 	github.com/alexliesenfeld/health v0.8.0
 	github.com/andybalholm/brotli v1.0.6 // indirect
-	github.com/chromedp/cdproto v0.0.0-20231101223124-24f5925b5980
+	github.com/chromedp/cdproto v0.0.0-20231114014204-3e458d5176f9
 	github.com/chromedp/chromedp v0.9.3
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/uuid v1.4.0
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
-	github.com/hashicorp/go-retryablehttp v0.7.4
+	github.com/hashicorp/go-retryablehttp v0.7.5
-	github.com/klauspost/compress v1.17.2 // indirect
+	github.com/klauspost/compress v1.17.3 // indirect
 	github.com/klauspost/pgzip v1.2.6 // indirect
-	github.com/labstack/echo/v4 v4.11.2
+	github.com/labstack/echo/v4 v4.11.3
-	github.com/labstack/gommon v0.4.0
+	github.com/labstack/gommon v0.4.1
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mholt/archiver/v3 v3.5.1
 	github.com/microcosm-cc/bluemonday v1.0.26
@@ -27,12 +27,12 @@ require (
 	github.com/ulikunitz/xz v0.5.11 // indirect
 	go.uber.org/multierr v1.11.0
 	go.uber.org/zap v1.26.0
-	golang.org/x/crypto v0.14.0 // indirect
+	golang.org/x/crypto v0.15.0 // indirect
-	golang.org/x/image v0.13.0 // indirect
+	golang.org/x/image v0.14.0 // indirect
-	golang.org/x/net v0.17.0
+	golang.org/x/net v0.18.0
 	golang.org/x/sync v0.5.0
 	golang.org/x/sys v0.14.0 // indirect
-	golang.org/x/term v0.13.0
+	golang.org/x/term v0.14.0
 	golang.org/x/text v0.14.0
 )
 

go.sum

@@ -10,13 +10,12 @@ github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6r
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/chromedp/cdproto v0.0.0-20231011050154-1d073bb38998/go.mod h1:GKljq0VrfU4D5yc+2qA6OVr8pmO/MBbPEWqWQ/oqGEs=
-github.com/chromedp/cdproto v0.0.0-20231101223124-24f5925b5980 h1:/nOO3ctHFqUmUwK5EdItjTCRQQCTcxWU7aJgyjFGtEc=
+github.com/chromedp/cdproto v0.0.0-20231114014204-3e458d5176f9 h1:e3tMnG8i9SfKOilykpprojNk3a49O4dn+wqZsam1qYQ=
-github.com/chromedp/cdproto v0.0.0-20231101223124-24f5925b5980/go.mod h1:GKljq0VrfU4D5yc+2qA6OVr8pmO/MBbPEWqWQ/oqGEs=
+github.com/chromedp/cdproto v0.0.0-20231114014204-3e458d5176f9/go.mod h1:GKljq0VrfU4D5yc+2qA6OVr8pmO/MBbPEWqWQ/oqGEs=
 github.com/chromedp/chromedp v0.9.3 h1:Wq58e0dZOdHsxaj9Owmfcf+ibtpYN1N0FWVbaxa/esg=
 github.com/chromedp/chromedp v0.9.3/go.mod h1:NipeUkUcuzIdFbBP8eNNvl9upcceOfWzoJn6cRe4ksA=
 github.com/chromedp/sysutil v1.0.0 h1:+ZxhTpfpZlmchB58ih/LBHX52ky7w2VhQVKQMucy3Ic=
 github.com/chromedp/sysutil v1.0.0/go.mod h1:kgWmDdq8fTzXYcKIBqIYvRRTnYb9aNS9moAV0xufSww=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dsnet/compress v0.0.2-0.20210315054119-f66993602bf5 h1:iFaUwBSo5Svw6L7HYpRu/0lE3e0BaElwnNO1qkNQxBY=
@@ -44,8 +43,8 @@ github.com/hashicorp/go-cleanhttp v0.5.2 h1:035FKYIWjmULyFRBKPs8TBQoi0x6d9G4xc9n
 github.com/hashicorp/go-cleanhttp v0.5.2/go.mod h1:kO/YDlP8L1346E6Sodw+PrpBSV4/SoxCXGY6BqNFT48=
 github.com/hashicorp/go-hclog v0.9.2 h1:CG6TE5H9/JXsFWJCfoIVpKFIkFe6ysEuHirp4DxCsHI=
 github.com/hashicorp/go-hclog v0.9.2/go.mod h1:5CU+agLiy3J7N7QjHK5d05KxGsuXiQLrjA0H7acj2lQ=
-github.com/hashicorp/go-retryablehttp v0.7.4 h1:ZQgVdpTdAL7WpMIwLzCfbalOcSUdkDZnpUv3/+BxzFA=
+github.com/hashicorp/go-retryablehttp v0.7.5 h1:bJj+Pj19UZMIweq/iie+1u5YCdGrnxCT9yvm0e+Nd5M=
-github.com/hashicorp/go-retryablehttp v0.7.4/go.mod h1:Jy/gPYAdjqffZ/yFGCFV2doI5wjtH1ewM9u8iYVjtX8=
+github.com/hashicorp/go-retryablehttp v0.7.5/go.mod h1:Jy/gPYAdjqffZ/yFGCFV2doI5wjtH1ewM9u8iYVjtX8=
 github.com/hhrutter/lzw v1.0.0 h1:laL89Llp86W3rRs83LvKbwYRx6INE8gDn0XNb1oXtm0=
 github.com/hhrutter/lzw v1.0.0/go.mod h1:2HC6DJSn/n6iAZfgM3Pg+cP1KxeWc3ezG8bBqW5+WEo=
 github.com/hhrutter/tiff v1.0.1 h1:MIus8caHU5U6823gx7C6jrfoEvfSTGtEFRiM8/LOzC0=
@@ -54,8 +53,8 @@ github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8Hm
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/klauspost/compress v1.4.1/go.mod h1:RyIbtBH6LamlWaDj8nUwkbUhJ87Yi3uG0guNDohfE1A=
 github.com/klauspost/compress v1.11.4/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
-github.com/klauspost/compress v1.17.2 h1:RlWWUY/Dr4fL8qk9YG7DTZ7PDgME2V4csBXA8L/ixi4=
+github.com/klauspost/compress v1.17.3 h1:qkRjuerhUU1EmXLYGkSH6EZL+vPSxIrYjLNAK4slzwA=
-github.com/klauspost/compress v1.17.2/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
+github.com/klauspost/compress v1.17.3/go.mod h1:/dCuZOvVtNoHsyb+cuJD3itjs3NbnF6KH9zAO4BDxPM=
 github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/klauspost/pgzip v1.2.5/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
@@ -64,18 +63,16 @@ github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/labstack/echo/v4 v4.11.2 h1:T+cTLQxWCDfqDEoydYm5kCobjmHwOwcv4OJAPHilmdE=
+github.com/labstack/echo/v4 v4.11.3 h1:Upyu3olaqSHkCjs1EJJwQ3WId8b8b1hxbogyommKktM=
-github.com/labstack/echo/v4 v4.11.2/go.mod h1:UcGuQ8V6ZNRmSweBIJkPvGfwCMIlFmiqrPqiEBfPYws=
+github.com/labstack/echo/v4 v4.11.3/go.mod h1:UcGuQ8V6ZNRmSweBIJkPvGfwCMIlFmiqrPqiEBfPYws=
-github.com/labstack/gommon v0.4.0 h1:y7cvthEAEbU0yHOf4axH8ZG2NH8knB9iNSoTO8dyIk8=
+github.com/labstack/gommon v0.4.1 h1:gqEff0p/hTENGMABzezPoPSRtIh1Cvw0ueMOe0/dfOk=
-github.com/labstack/gommon v0.4.0/go.mod h1:uW6kP17uPlLJsD3ijUYn3/M5bAxtlZhMI6m3MFxTMTM=
+github.com/labstack/gommon v0.4.1/go.mod h1:TyTrpPqxR5KMk8LKVtLmfMjeQ5FEkBYdxLYPw/WfrOM=
 github.com/ledongthuc/pdf v0.0.0-20220302134840-0c2507a12d80 h1:6Yzfa6GP0rIo/kULo2bwGEkFvCePZ3qHDDTC3/J9Swo=
 github.com/ledongthuc/pdf v0.0.0-20220302134840-0c2507a12d80/go.mod h1:imJHygn/1yfhB7XSJJKlFZKl/J+dCPAknuiaGOshXAs=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
-github.com/mattn/go-colorable v0.1.11/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
-github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
@@ -118,11 +115,9 @@ github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.5.0 h1:1zr/of2m5FGMsad5YfcqgdqdWrIhu+EBEJRhR1U7z/c=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/ulikunitz/xz v0.5.8/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
@@ -131,7 +126,6 @@ github.com/ulikunitz/xz v0.5.11 h1:kpFauv27b6ynzBNT/Xy+1k+fK4WswhN/6PN5WhFAGw8=
 github.com/ulikunitz/xz v0.5.11/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasttemplate v1.2.1/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
 github.com/valyala/fasttemplate v1.2.2 h1:lxLXG0uE3Qnshl9QyaK6XJxMXlQZELvChBOCmQD0Loo=
 github.com/valyala/fasttemplate v1.2.2/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
 github.com/xi2/xz v0.0.0-20171230120015-48954b6210f8 h1:nIPpBwaJSVYIxUFsDv3M8ofmx9yWTog9BfvIu0q41lo=
@@ -142,23 +136,20 @@ go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
 go.uber.org/zap v1.26.0 h1:sI7k6L95XOKS281NhVKOFCUNIvv9e0w4BF8N3u+tCRo=
 go.uber.org/zap v1.26.0/go.mod h1:dtElttAiwGvoJ/vj4IwHBS/gXsEu/pZ50mUIRWuG0so=
-golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
-golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
-golang.org/x/image v0.13.0 h1:3cge/F/QTkNLauhf2QoE9zp+7sr+ZcL4HnoZmdwg9sg=
+golang.org/x/image v0.14.0 h1:tNgSxAFe3jC4uYqvZdTr84SZoM1KfwdC9SKIFrLjFn4=
-golang.org/x/image v0.13.0/go.mod h1:6mmbMOeV28HuMTgA6OSRkdXKYw/t5W9Uwn2Yv1r3Yxk=
+golang.org/x/image v0.14.0/go.mod h1:HUYqC05R2ZcZ3ejNQsIHQDQiwWM4JBqmm6MKANTp4LE=
-golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
+golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
-golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
 golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
 golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20211103235746-7861aae1554b/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
 golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
+golang.org/x/term v0.14.0 h1:LGK9IlZ8T9jvdy6cTdfKUCltatMFOehAQo9SRC46UQ8=
-golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
+golang.org/x/term v0.14.0/go.mod h1:TySc+nGkYR6qt8km8wUhuFRTVSMIX3XPR58y2lC8vww=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -170,7 +161,5 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntN
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

pkg/gotenberg/mocks.go

@@ -109,6 +109,15 @@ func (provider *LoggerProviderMock) Logger(mod Module) (*zap.Logger, error) {
 	return provider.LoggerMock(mod)
 }
 
+// MetricsProviderMock is a mock for the [MetricsProvider] interface.
+type MetricsProviderMock struct {
+	MetricsMock func() ([]Metric, error)
+}
+
+func (provider *MetricsProviderMock) Metrics() ([]Metric, error) {
+	return provider.MetricsMock()
+}
+
 // Interface guards.
 var (
 	_ Module            = (*ModuleMock)(nil)
@@ -118,4 +127,5 @@ var (
 	_ Process           = (*ProcessMock)(nil)
 	_ ProcessSupervisor = (*ProcessSupervisorMock)(nil)
 	_ LoggerProvider    = (*LoggerProviderMock)(nil)
+	_ MetricsProvider   = (*MetricsProviderMock)(nil)
 )

pkg/gotenberg/mocks_test.go

@@ -162,3 +162,16 @@ func TestLoggerProviderMock(t *testing.T) {
 		t.Errorf("expected no error from LoggerProviderMock.Logger, but got: %v", err)
 	}
 }
+
+func TestMetricsProviderMock(t *testing.T) {
+	mock := &MetricsProviderMock{
+		MetricsMock: func() ([]Metric, error) {
+			return nil, nil
+		},
+	}
+
+	_, err := mock.Metrics()
+	if err != nil {
+		t.Errorf("expected no error from MetricsProviderMock.Metrics, but got: %v", err)
+	}
+}

pkg/modules/prometheus/doc.go

@@ -1,3 +1,5 @@
 // Package prometheus provides a module which collects metrics and exposes them
 // via an HTTP route.
+//
+// See: https://prometheus.io/.
 package prometheus

pkg/modules/prometheus/prometheus.go

@@ -17,7 +17,7 @@ import (
 )
 
 func init() {
-	gotenberg.MustRegisterModule(Prometheus{})
+	gotenberg.MustRegisterModule(new(Prometheus))
 }
 
 // Prometheus is a module which collects metrics and exposes them via an HTTP
@@ -32,8 +32,8 @@ type Prometheus struct {
 	registry *prometheus.Registry
 }
 
-// Descriptor returns a Prometheus's module descriptor.
+// Descriptor returns a [Prometheus]'s module descriptor.
-func (Prometheus) Descriptor() gotenberg.ModuleDescriptor {
+func (mod *Prometheus) Descriptor() gotenberg.ModuleDescriptor {
 	return gotenberg.ModuleDescriptor{
 		ID: "prometheus",
 		FlagSet: func() *flag.FlagSet {
@@ -88,7 +88,7 @@ func (mod *Prometheus) Provision(ctx *gotenberg.Context) error {
 }
 
 // Validate validates the module properties.
-func (mod Prometheus) Validate() error {
+func (mod *Prometheus) Validate() error {
 	if mod.disableCollect {
 		// Exit early.
 		return nil
@@ -120,7 +120,7 @@ func (mod Prometheus) Validate() error {
 }
 
 // Start starts the collect.
-func (mod Prometheus) Start() error {
+func (mod *Prometheus) Start() error {
 	if mod.disableCollect {
 		// Exit early.
 		return nil
@@ -149,7 +149,7 @@ func (mod Prometheus) Start() error {
 }
 
 // StartupMessage returns a custom startup message.
-func (mod Prometheus) StartupMessage() string {
+func (mod *Prometheus) StartupMessage() string {
 	if mod.disableCollect {
 		return "collect disabled"
 	}
@@ -158,12 +158,12 @@ func (mod Prometheus) StartupMessage() string {
 }
 
 // Stop does nothing.
-func (mod Prometheus) Stop(_ context.Context) error {
+func (mod *Prometheus) Stop(ctx context.Context) error {
 	return nil
 }
 
 // Routes returns the HTTP route.
-func (mod Prometheus) Routes() ([]api.Route, error) {
+func (mod *Prometheus) Routes() ([]api.Route, error) {
 	if mod.disableCollect {
 		return nil, nil
 	}

pkg/modules/prometheus/prometheus_test.go

@@ -11,34 +11,8 @@ import (
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
 )
 
-type ProtoModule struct {
-	descriptor func() gotenberg.ModuleDescriptor
-}
-
-func (mod ProtoModule) Descriptor() gotenberg.ModuleDescriptor {
-	return mod.descriptor()
-}
-
-type ProtoValidator struct {
-	ProtoModule
-	validate func() error
-}
-
-func (mod ProtoValidator) Validate() error {
-	return mod.validate()
-}
-
-type ProtoMetricsProvider struct {
-	ProtoValidator
-	metrics func() ([]gotenberg.Metric, error)
-}
-
-func (mod ProtoMetricsProvider) Metrics() ([]gotenberg.Metric, error) {
-	return mod.metrics()
-}
-
 func TestPrometheus_Descriptor(t *testing.T) {
-	descriptor := Prometheus{}.Descriptor()
+	descriptor := new(Prometheus).Descriptor()
 
 	actual := reflect.TypeOf(descriptor.New())
 	expect := reflect.TypeOf(new(Prometheus))
@@ -49,19 +23,20 @@ func TestPrometheus_Descriptor(t *testing.T) {
 }
 
 func TestPrometheus_Provision(t *testing.T) {
-	for i, tc := range []struct {
+	for _, tc := range []struct {
+		scenario      string
 		ctx           *gotenberg.Context
 		expectMetrics []gotenberg.Metric
-		expectErr     bool
+		expectError   bool
 	}{
 		{
+			scenario: "disable collect",
 			ctx: func() *gotenberg.Context {
 				fs := new(Prometheus).Descriptor().FlagSet
 				err := fs.Parse([]string{"--prometheus-disable-collect=true"})
 				if err != nil {
 					t.Fatalf("expected no error but got: %v", err)
 				}
-
 				return gotenberg.NewContext(
 					gotenberg.ParsedFlags{
 						FlagSet: fs,
@@ -69,20 +44,25 @@ func TestPrometheus_Provision(t *testing.T) {
 					nil,
 				)
 			}(),
+			expectError: false,
 		},
 		{
+			scenario: "invalid metrics provider",
 			ctx: func() *gotenberg.Context {
-				mod := struct{ ProtoMetricsProvider }{}
+				mod := &struct {
-				mod.descriptor = func() gotenberg.ModuleDescriptor {
+					gotenberg.ModuleMock
+					gotenberg.ValidatorMock
+					gotenberg.MetricsProviderMock
+				}{}
+				mod.DescriptorMock = func() gotenberg.ModuleDescriptor {
 					return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return mod }}
 				}
-				mod.validate = func() error {
+				mod.ValidateMock = func() error {
 					return errors.New("foo")
 				}
-				mod.metrics = func() ([]gotenberg.Metric, error) {
+				mod.MetricsMock = func() ([]gotenberg.Metric, error) {
 					return nil, nil
 				}
-
 				return gotenberg.NewContext(
 					gotenberg.ParsedFlags{
 						FlagSet: new(Prometheus).Descriptor().FlagSet,
@@ -92,21 +72,25 @@ func TestPrometheus_Provision(t *testing.T) {
 					},
 				)
 			}(),
-			expectErr: true,
+			expectError: true,
 		},
 		{
+			scenario: "invalid metrics from metrics provider",
 			ctx: func() *gotenberg.Context {
-				mod := struct{ ProtoMetricsProvider }{}
+				mod := &struct {
-				mod.descriptor = func() gotenberg.ModuleDescriptor {
+					gotenberg.ModuleMock
+					gotenberg.ValidatorMock
+					gotenberg.MetricsProviderMock
+				}{}
+				mod.DescriptorMock = func() gotenberg.ModuleDescriptor {
 					return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return mod }}
 				}
-				mod.validate = func() error {
+				mod.ValidateMock = func() error {
 					return nil
 				}
-				mod.metrics = func() ([]gotenberg.Metric, error) {
+				mod.MetricsMock = func() ([]gotenberg.Metric, error) {
 					return nil, errors.New("foo")
 				}
-
 				return gotenberg.NewContext(
 					gotenberg.ParsedFlags{
 						FlagSet: new(Prometheus).Descriptor().FlagSet,
@@ -116,18 +100,23 @@ func TestPrometheus_Provision(t *testing.T) {
 					},
 				)
 			}(),
-			expectErr: true,
+			expectError: true,
 		},
 		{
+			scenario: "provision success",
 			ctx: func() *gotenberg.Context {
-				mod := struct{ ProtoMetricsProvider }{}
+				mod := &struct {
-				mod.descriptor = func() gotenberg.ModuleDescriptor {
+					gotenberg.ModuleMock
+					gotenberg.ValidatorMock
+					gotenberg.MetricsProviderMock
+				}{}
+				mod.DescriptorMock = func() gotenberg.ModuleDescriptor {
 					return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return mod }}
 				}
-				mod.validate = func() error {
+				mod.ValidateMock = func() error {
 					return nil
 				}
-				mod.metrics = func() ([]gotenberg.Metric, error) {
+				mod.MetricsMock = func() ([]gotenberg.Metric, error) {
 					return []gotenberg.Metric{
 						{
 							Name:        "foo",
@@ -135,7 +124,6 @@ func TestPrometheus_Provision(t *testing.T) {
 						},
 					}, nil
 				}
-
 				return gotenberg.NewContext(
 					gotenberg.ParsedFlags{
 						FlagSet: new(Prometheus).Descriptor().FlagSet,
@@ -151,58 +139,73 @@ func TestPrometheus_Provision(t *testing.T) {
 					Description: "Bar.",
 				},
 			},
+			expectError: false,
 		},
 	} {
-		mod := new(Prometheus)
+		t.Run(tc.scenario, func(t *testing.T) {
-		err := mod.Provision(tc.ctx)
+			mod := new(Prometheus)
+			err := mod.Provision(tc.ctx)
 
-		if !reflect.DeepEqual(mod.metrics, tc.expectMetrics) {
+			if !reflect.DeepEqual(mod.metrics, tc.expectMetrics) {
-			t.Errorf("test %d: expected %+v, but got: %+v", i, tc.expectMetrics, mod.metrics)
+				t.Fatalf("expected metrics %+v, but got: %+v", tc.expectMetrics, mod.metrics)
-		}
+			}
 
-		if tc.expectErr && err == nil {
+			if !tc.expectError && err != nil {
-			t.Errorf("test %d: expected error but got: %v", i, err)
+				t.Fatalf("expected no error but got: %v", err)
-		}
+			}
 
-		if !tc.expectErr && err != nil {
+			if tc.expectError && err == nil {
-			t.Errorf("test %d: expected no error but got: %v", i, err)
+				t.Fatal("expected error but got none")
-		}
+			}
+		})
 	}
 }
 
 func TestPrometheus_Validate(t *testing.T) {
-	for i, tc := range []struct {
+	for _, tc := range []struct {
+		scenario       string
 		namespace      string
 		metrics        []gotenberg.Metric
 		disableCollect bool
-		expectErr      bool
+		expectError    bool
 	}{
 		{
+			scenario:       "collect disabled",
+			namespace:      "foo",
 			disableCollect: true,
+			expectError:    false,
 		},
 		{
-			namespace: "",
+			scenario:       "empty namespace",
-			expectErr: true,
+			namespace:      "",
+			disableCollect: false,
+			expectError:    true,
 		},
 		{
+			scenario:  "empty metric name",
 			namespace: "foo",
 			metrics: []gotenberg.Metric{
 				{
 					Name: "",
 				},
 			},
-			expectErr: true,
+			disableCollect: false,
+			expectError:    true,
 		},
 		{
+			scenario:  "nil read metric method",
 			namespace: "foo",
 			metrics: []gotenberg.Metric{
 				{
 					Name: "foo",
+					Read: nil,
 				},
 			},
-			expectErr: true,
+			disableCollect: false,
+			expectError:    true,
 		},
 		{
+			scenario:  "already registered metric",
 			namespace: "foo",
 			metrics: []gotenberg.Metric{
 				{
@@ -218,9 +221,11 @@ func TestPrometheus_Validate(t *testing.T) {
 					},
 				},
 			},
-			expectErr: true,
+			disableCollect: false,
+			expectError:    true,
 		},
 		{
+			scenario:  "validate success",
 			namespace: "foo",
 			metrics: []gotenberg.Metric{
 				{
@@ -236,35 +241,41 @@ func TestPrometheus_Validate(t *testing.T) {
 					},
 				},
 			},
+			disableCollect: false,
+			expectError:    false,
 		},
 	} {
-		mod := Prometheus{
+		t.Run(tc.scenario, func(t *testing.T) {
-			namespace:      tc.namespace,
+			mod := &Prometheus{
-			metrics:        tc.metrics,
+				namespace:      tc.namespace,
-			disableCollect: tc.disableCollect,
+				metrics:        tc.metrics,
-		}
+				disableCollect: tc.disableCollect,
+			}
+			err := mod.Validate()
 
-		err := mod.Validate()
+			if !tc.expectError && err != nil {
+				t.Fatalf("expected no error but got: %v", err)
+			}
 
-		if tc.expectErr && err == nil {
+			if tc.expectError && err == nil {
-			t.Errorf("test %d: expected error but got: %v", i, err)
+				t.Fatal("expected error but got none")
-		}
+			}
-
+		})
-		if !tc.expectErr && err != nil {
-			t.Errorf("test %d: expected no error but got: %v", i, err)
-		}
 	}
 }
 
 func TestPrometheus_Start(t *testing.T) {
-	for i, tc := range []struct {
+	for _, tc := range []struct {
+		scenario       string
 		metrics        []gotenberg.Metric
 		disableCollect bool
 	}{
 		{
+			scenario:       "collect disabled",
 			disableCollect: true,
 		},
 		{
+			scenario: "start success",
 			metrics: []gotenberg.Metric{
 				{
 					Name: "foo",
@@ -275,86 +286,75 @@ func TestPrometheus_Start(t *testing.T) {
 			},
 		},
 	} {
-		mod := Prometheus{
+		t.Run(tc.scenario, func(t *testing.T) {
-			namespace:      "foo",
+			mod := &Prometheus{
-			interval:       time.Duration(1) * time.Second,
+				namespace:      "foo",
-			metrics:        tc.metrics,
+				interval:       time.Duration(1) * time.Second,
-			disableCollect: tc.disableCollect,
+				metrics:        tc.metrics,
-			registry:       prometheus.NewRegistry(),
+				disableCollect: tc.disableCollect,
-		}
+				registry:       prometheus.NewRegistry(),
+			}
 
-		err := mod.Start()
+			err := mod.Start()
-		if err != nil {
+			if err != nil {
-			t.Errorf("test %d: expected no error but got: %v", i, err)
+				t.Errorf("expected no error but got: %v", err)
-		}
+			}
+		})
 	}
 }
 
 func TestPrometheus_StartupMessage(t *testing.T) {
-	for i, tc := range []struct {
+	mod := new(Prometheus)
-		disableCollect bool
-		expectMessage  string
-	}{
-		{
-			disableCollect: true,
-			expectMessage:  "collect disabled",
-		},
-		{
-			expectMessage: "collecting metrics",
-		},
-	} {
-		mod := Prometheus{
-			disableCollect: tc.disableCollect,
-		}
 
-		actual := mod.StartupMessage()
+	mod.disableCollect = true
-		if actual != tc.expectMessage {
+	disableCollectMsg := mod.StartupMessage()
-			t.Errorf("test %d: expected '%s' but got '%s'", i, tc.expectMessage, actual)
+
-		}
+	mod.disableCollect = false
+	noDisableCollectMsg := mod.StartupMessage()
+
+	if disableCollectMsg == noDisableCollectMsg {
+		t.Errorf("expected differrent startup messages if collect is disabled or not, but got '%s'", disableCollectMsg)
 	}
 }
 
 func TestPrometheus_Stop(t *testing.T) {
-	err := Prometheus{}.Stop(nil)
+	err := new(Prometheus).Stop(nil)
 	if err != nil {
 		t.Errorf("expected no error but got: %v", err)
 	}
 }
 
 func TestPrometheus_Routes(t *testing.T) {
-	for i, tc := range []struct {
+	for _, tc := range []struct {
-		expectRoutes   int
+		scenario       string
 		disableCollect bool
+		expectRoutes   int
 	}{
 		{
+			scenario:       "collect disabled",
 			disableCollect: true,
+			expectRoutes:   0,
 		},
 		{
-			expectRoutes: 1,
+			scenario:       "routes not disabled",
+			disableCollect: false,
+			expectRoutes:   1,
 		},
 	} {
-		mod := Prometheus{
+		t.Run(tc.scenario, func(t *testing.T) {
-			disableCollect: tc.disableCollect,
+			mod := &Prometheus{
-			registry:       prometheus.NewRegistry(),
+				disableCollect: tc.disableCollect,
-		}
+				registry:       prometheus.NewRegistry(),
+			}
 
-		routes, err := mod.Routes()
+			routes, err := mod.Routes()
-		if err != nil {
+			if err != nil {
-			t.Fatalf("test %d: expected no error but got: %v", i, err)
+				t.Fatalf("expected no error but got: %v", err)
-		}
+			}
 
-		if tc.expectRoutes != len(routes) {
+			if tc.expectRoutes != len(routes) {
-			t.Errorf("test %d: expected %d routes but got %d", i, tc.expectRoutes, len(routes))
+				t.Errorf("expected %d routes but got %d", tc.expectRoutes, len(routes))
-		}
+			}
+		})
 	}
 }
-
-// Interface guards.
-var (
-	_ gotenberg.Module          = (*ProtoModule)(nil)
-	_ gotenberg.Validator       = (*ProtoValidator)(nil)
-	_ gotenberg.Module          = (*ProtoValidator)(nil)
-	_ gotenberg.MetricsProvider = (*ProtoMetricsProvider)(nil)
-	_ gotenberg.Module          = (*ProtoMetricsProvider)(nil)
-	_ gotenberg.Validator       = (*ProtoMetricsProvider)(nil)
-)